 

_UBRARY
M'Chigan State
University

 

 

 

PLACE IN RETURN Box to remove this checkout from your record.
To AVOID FINES return on or before date due.
MAY BE RECALLED with earlier due date ifrequeSted.

 

DATE DUE DATE DUE DATE DUE

 

iﬁo‘htzgss

 

—€Z.{ i 3
SEP 2 i 2011

 

 

 

 

 

 

 

 

 

 

 

 

 

6/01 cJCIRC/DateDue.p65-p.15

EXERCISE AND CLINICAL DEPRESSION: EXAMINING PSYCHOLOGICAL
MECHANISMS

By

Lynette Leigh Craﬁ

A DISSERTATION
Submited to
Michigan State University
in partial fulﬁllment of the requirements
for the degree of
DOCTOR OF PHILOSOPHY
Department of Kinesiology

2002

ABSTRACT

EXERCISE AND CLINICAL DEPRESSION: EXAMINING PSYCHOLOGICAL
MECHANISM

By

Lynette Leigh Craﬁ

Chronic exercise interventions have been shown to be associated with a reduction
in the symptoms of clinical depression (Craft & Landers, 1998; North, McCullagh, &
Tran, 1990). However, the mechanisms for the antidepressant effects of exercise remain
poorly understood. This study examined two previously proposed psychological
mechanisms: self-efﬁcacy and distraction. Further, the relationship between transient
mood elevation following acute bouts of exercise and symptoms of depression was
explored. Nineteen clinically depressed women, aged 43.21 (SD = 13.23) years, served
as study participants. Dependent measures were severity of depression, coping self-
eﬂicacy, and response style (i.e. rumination and distraction). Participants chose to
participate in either the control group or a 9-week exercise intervention group.
Dependent variables were measured at study entry, 3, 6, and 9 weeks later. Repeated
measures multivariate analysis of variance indicated that exercise was associated with a
reduction in symptoms of depression, an enhancement in coping self-efﬁcacy, and a
reduction in the tendency to use a ruminative response style. Regression analyses
showed that coping self-efficacy had a signiﬁcant negative relationship with depression
among exercise group participants. Mood data revealed that depressed women
experienced mood elevation following acute bouts of exercise and that this enhanced

mood lasted for at least 15 min following exercise. Data did not support the prediction of

an association between transient mood changes following acute exercise and severity of

depression.

ACKNOWLEDGEMENTS

I would like to thank each of my committee members, Dr. Deborah F eltz, Dr.
James Pivamik, Dr. Christopher Womack, and Dr. Susan Bentley, for their guidance,
critical review, and mentoring throughout the course of this study.

I am also indebted to each of my study participants. This project would not have
been possible without their willingness to participate. They have not only helped me
through their contribution, but hopeﬁJlly other women with depression as well.

Special thanks to Patricia Sawyer and Tim Bauer for their assistance in making
the aerobics videotape provided to exercise group members.

Finally, this degree would not have been possible without the love and support of
my family and friends. I owe everything to my parents, Mark and Helen Craﬁ, who have

constantly reminded me that all things are possible when taken one step at a time.

iv

TABLE OF CONTENTS

 

Page
LIST OF TABLES ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, vii
LIST OF FIGURES ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, viii
CHAPTER 1
INTRODUCTION ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 1
Mechanisms for the Antidepressant Effects of Exercise ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 2
Self-efficacy ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 3
Distraction ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 5
Mood Elevation Following Acute Bouts of Exercise ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 8
Purpose of the Study ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, l 1
Study Hypotheses ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 1 1
CHAPTER 2
REVIEW OF THE LITERATURE ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 13
Mechanisms for the Antidepressant Effects of Exercise ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, l7
Physiological Mechanisms ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 18
Psychological Mechanisms ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 20
Self-Efﬁcacy ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 20
Distraction ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 25
Mood Elevation Following Acute Bouts of Exercise ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 28
CHAPTER 3
METHODS .............................................................................................................................. 34
Participants and Design ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 34
Questionnaires ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 36
Procedurewwmmmmwm.WW“, ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 38
Analyses ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 41
CHAPTER 4
RESULTS ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 43
CHAPTER 5
DISCUSSION ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 59
Overall Effects of Exercise on Depression ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 59
Exercise, Coping Self-efficacy and Depression ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 61
Exercise, Response Style, and Depression ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 63
Exercise, Mood Elevation, and Depression ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 66
Conclusions ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 71

Limitations

APPENDIX A
Institutional Review Board Approval and Informed Consent ..............................................

APPENDIX B
Demographic Questionnaire ................................................................................................... .

APPENDIX C
Exercise program readiness questionnaire ............................................................................

APPENDIX D
Beck Depression Inventory-II ................................................................................................

APPENDIX E
Depression Coping Self-Efﬁcacy Scale ................................................................................

APPENDIX F
Response Styles Questionnaire ______________________________________________________________________________________________

APPENDIX G
Rating of Perceived Exertion Scale ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,

APPENDIX H
Rating of Mood and Enjoyment of Exercise Scales .............................................................

BIBLIOGRAPHY

...................................................................................................................

vi

78

80

82

87

9O

93

95

97

LIST OF TABLES

Page
TABLE 1
Subject Characteristics ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 44
TABLE 2
Means and Standard Deviations Across Time on BDI-II, DCSES, and RSQ ,,,,,,,,,,,,,,,,,,,, 45
TABLE 3
Means and Standard Deviations for Exercise Mood Variables ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 54
TABLE 4
Correlations Among Mood Variables and Dependent Variables at Time 1 ,,,,,,,,,,,,,,,,,,,,,,, 56
TABLE 5
Correlations Among Mood Variables and Dependent Variables at Time 2 ,,,,,,,,,,,,,,,,,,,,,,, 57
TABLE 6
Correlations Among Mood Variables and Dependent Variables at Time 3 ,,,,,,,,,,,,,,,,,,,,,,, 58

vii

LIST OF FIGURES

Page
FIGURE 1
Group X Time Interaction for BDI-II Score .......................................................................... 47
Figure 2
Group X Time Interaction for DCSES Score ......................................................................... 49
Figure 3
Main Effect for Time for RRS Score ...................................................................................... 51
Figure 4
Scores on DRS 52

viii

CHAPTER ONE
Introduction

Clinical depression affects roughly 9.5% of the United States (US) adult
population (National Institutes of Mental Health, 2001). Depression is characterized by a
variety of symptoms including feelings of sadness, irritability, changes in sleep and
appetite, feelings of worthlessness, loss of pleasure from enjoyable activities, and
psychomotor retardation (American Psychiatric Association, 1994). Depression is twice
as prevalent in females as males and the risk of a recurrence can be as high as 50-90%
(Preskom, 1999; Stahl, 1996). This chronic illness is very costly to the US. health care
system and each year over 40 billion dollars are spent on lost productivity and medical
treatment related to depression (Zerihun, 2001).

Traditional treatments for clinical depression have primarily included
psychotherapy and pharmacological interventions (Johnson & Miller, 1994; Preskom,
1999). Unfortunately, these therapies are often ineffective and, for some, also have
extremely adverse side effects (Byrne & Byrne, 1993; Leith, 1994; Mutrie, 2000; Raglin,
1990; Stahl, 1996). Furthermore, health care changes in the US. have led to time
constraints for therapy and limits in payment for mental health services (Mirin & Sederer,
1994). Therefore, practitioners and researchers have begun to examine possible
alternatives in the treatment of this disorder.

Exercise has been proposed as one plausible adjunct or alternative to the
traditional treatments for depression. The ﬁrst studies on exercise and depression were
cross-sectional, comparing the physical activity and physical capacity levels of depressed

and non-depressed individuals (Martinsen, Strand, Paulsson, & Kaggesstad, 1989;

Morgan, 1969, 1970). Exercise intervention studies followed, examining the efﬁcacy of
exercise in alleviating depression (Brown et al., 1992; Dimeo, Baurer, Varahm, Proest, &
Halter, 2001; Doyne, Chambless, & Beutler, 1983; McNeil, LeBlanc & Joyner, 1991;
Veale et al., 1992 ). Researchers have also investigated whether certain types of exercise
are more effective in alleviating depression than others (Doyne et al., 1987; Martinsen,
Hoffart, & Solberg, 1989; Sing, Clements, & Fiatarone, 1997). Exercise has been
compared to more traditional treatments such as psychotherapy, behavioral modiﬁcation,
and medication (Babyak et al., 2000; Blumenthal et al., 1999; Greist et al., 1979; Kleine
et al., 1985). Meta-analytic studies also suggest that chronic exercise is effective in
alleviating symptoms of depression, that exercise is as effective as most traditional
treatments, that exercise appears effective across genders, and that mode, frequency, and
intensity of exercise do not appear to moderate the effect (Craﬁ & Landers, 1998; North,
McCullagh, & Tran, 1990). While the research is relatively clear that chronic exercise
helps alleviate symptoms of depression our knowledge remains limited regarding the
mechanisms by which exercise exerts its effect.
Mechanisms for the Antidepressant Effects of Exercise

The overwhelming research support for exercise as an effective means to alleviate
depression has led some researchers to examine potential causal links between exercise
and depression. While there are researchers who contend that exercise causes a reduction
in depression (Mutrie, 2000), others argue that more information is needed before a
causal association can be conﬁrmed (Landers & Arent, 2001). Research to date has not
extensively examined the plausible mechanisms suggested in the literature. Therefore, it

appears that a better understanding of the mechanisms behind the antidepressant effects

of exercise would not only provide additional insight into a possible causal association,
but should also be helpful in the future use of exercise as an adjunct therapy in the
treatment of depression. Studies are needed to examine the potential physiological and
psychological mechanisms (Dunn, Trivedi, & O’Neil, 2001; Fox, 1999; Landers & Arent,
2001; Leith, 1994). Two psychological explanations that have received attention in the
literature and warrant further examination are self-efﬁcacy theory and the concept of
distraction.
Self-Efﬁcacy

Self-efﬁcacy, or the level of conﬁdence one feels to meet the challenge at hand,
has been proposed as one mechanism by which exercise may help reduce symptoms of
clinical depression. Self-efﬁcacy refers to the belief that one possesses the necessary
skills to complete a task as well as the confidence that the task can actually be completed
with the desired outcome obtained. Efﬁcacy beliefs direct choice of behavior, goals that
are chosen, persistence at a task, motivation and effort, expectations of suCcess, and how
one responds affectively (Bandura, 1997). Bandura (1997) contends that healthy
individuals are able to regulate goal directed behaviors and are also able to use regulatory
strategies for their thoughts, feelings, and emotions. This idea of self-regulation has led
to the investigation of the concept of coping self-efﬁcacy. People’s beliefs about their
ability to control a stressful situation and regulate their response to the situation is a
primary determinant of how they will respond. A low sense of self-control or coping
efﬁcacy can cause people to approach situations anxiously and with little conﬁdence to

obtain the desired outcome (Bandura, 1997).

Bandura (1997), utilizing self-efﬁcacy theory, describes how the low sense of
efﬁcacy of those with depression often leads to negative self-evaluations, negative
ruminations, and faulty styles of thinking. Further, depressed people often blame
themselves for negative life events and this negative explanatory style can worsen and
prolong their depression (Peterson & Seligman, 1984). Individuals with low efﬁcacy to
stop or restructure negative thoughts have also been shown to have higher levels of
depression (Kavanagh & Wilson, 1989).

Several different factors influence the development of efficacy beliefs (Bandura,
1997). The best source of efﬁcacy information appears to come from mastery
experiences. When an individual can repeatedly derive a course of action, follow a plan,
and meet the desired outcome in the face of changing situations and obstacles then he or
she is likely to feel highly efﬁcacious. On the contrary, repeated failures at such attempts
to navigate through life can lead to decreased feelings of self-efﬁcacy.

Exercise may provide an effective mode to enhance efﬁcacy beliefs based on its
ability to provide a meaningful mastery experience. According to Bandura (1997), in
order for an intervention to lead to enhanced coping self-efﬁcacy it must teach the
individual how to self-monitor behaviors, set goals, and utilize social support to maintain
the desired behaviors. Learning how to monitor exercise behaviors, set short and long
term exercise goals, and positive support from the exercise instructor and signiﬁcant
others can all contribute to feelings of mastery. Therefore, it is possible that the
antidepressant properties of exercise are related to enhanced feelings of efﬁcacy that

result from this mastery experience.

Research examining the relationship between physical activity and self-efﬁcacy
has predominately focused on the enhancement of physical self—efﬁcacy and efﬁcacy to
regulate exercise behaviors (Beniamini, Rubenstein, Zaichkowksy, & Crim, 1997; Ewart,
Stewart, Gillilan, & Kelemen, 1986; McAuley, 1992; McAuley & Coumeya, 1992;
McAuley, Lox, & Duncan, 1993). The relationship between exercise and self-efﬁcacy in
depressed patients has not been studied extensively and ﬁndings have been equivocal
(Brown, Welsh, Labbe, Vitulli, & Kulkarni, 1992; Singh, Clements, & F iatarone, 1997).
Furthermore, generalized feelings of efﬁcacy rather than coping self-efﬁcacy have been
the focus of the research to date. Enhanced feelings of coping have been associated with
exercise participation in anxious adults (Steptoe, Edwards, Moses, & Mathews, 1989),
however, as mentioned previously, this relationship has not been examined with the
clinically depressed. Therefore, the role that exercise can play in augmenting the coping
self-efﬁcacy of depressed patients needs ﬁthher investigation.

Distraction

The concept of distraction has also been promoted as a possible explanation for
the antidepressant effects of exercise. Some researchers (Bahrke & Morgan, 1978;
Gleser & Mendleberg, 1990; Johnsgard, 1989; Leith, 1994) have suggested that physical
activity serves as a distraction from worries, anxiety, and depressing thoughts. A theory
of depression that is conceptually related is the response styles theory (Nolen-Hoeksema,
1991). This theory discusses two different dispositional ways in which individuals
typically respond to feelings of depression and how these differing responses can affect
the severity and length of a depressive episode. Rumination is a response style that

involves the tendency to passively and repeatedly focus on one’s negative feelings and

the consequences of those feelings. Distraction refers to a response style in which the
individual busies herself in an engaging activity (i.e. a hobby, work) in an attempt to
focus on something other than the depressed mood.

Rumination is thought to have a negative influence on the course of depression.
Rumination may lead to negative thoughts and attributions about the self, past, present,
and future which can contribute to a continued depressed mood (Lyubomirsky & Nolen-
Hoeksema, 1995). Individuals who focus on their negative thoughts rather than engage in
activities to solve their problems are at risk for prolonged bouts of depression (Nolen-
Hoeksema, Parker, & Larson, 1994). Those who ruminate about their depression may
not engage in behaviors that provide the opportunity for positive reinforcement and an
enhanced sense of control (Lyubomirsky & Nolen-Hoeksema, 1993). Without such
opportunities, the depressed individual may experience feelings of helplessness, negative
evaluations of self, lowered expectancies for the ﬁrture, and a lack of motivation to meet
new challenges (Nolen-Hoeksema, 1991). Research related to response styles theory has
shown that women spend more time ruminating than men, that men tend to use
distraction more than women, and that individuals who ruminate generally have more
severe and longer lasting episodes of depression than those who use distraction as a
response style (Just & Alloy, 1997; Morrow & Nolen-Hoeksema, 1990; Nolen-Hoeksema
& Morrow, 1991; Nolen-Hoeksema, et al., 1993). Therefore, based on the current
research, a distraction response style appears to be associated with a more positive
outcome for those suffering from depression (Nolen-Hoeksema, 1991, 1998).

Nolen-Hoeksema (1991) cautions that not all activities are distracting. An

effective distracting activity engages the individual and has a high probability of

providing opportunities for positive reinforcement (Nolen-Hoeksema, 1991). The very
nature of exercise makes it a potentially distracting activity worthy of investigation.
When working out, people are often focused on training goals or attending to somatic
changes such as their breathing, heart rate, fatigue, or sore muscles (Leith, 1994).
Furthermore, exercise offers the opportunity for positive reinforcement as exercise goals
are met, daily workouts become less painful and fatiguing, and signiﬁcant others reward
the individual for taking a proactive role in the management of her symptoms. Therefore,
the antidepressant effects of exercise may result from the ability of exercise to provide
periodic distraction from negative thoughts and feelings of depression. As mentioned
previously, this temporary attenuation of depressed mood may allow for more effective
problem-solving behaviors.

Response styles theory has not yet been tested with depressed participants who
engage in an exercise program as a distracting activity. Exercise has been compared to
other distracting activities such as relaxation, assertiveness training, health education, and
social contact (Doyne et al., 1983; Klein et al., 1985; McNeil, LeBlanc, & Joyner, 1991;
Singh, Clements, & F iatarone, 1997). Results of these studies have been inconclusive
with exercise being more effective than some activities and similar to others in its ability
to aid in the reduction of depression. This line of research, however, has only examined
the overall effect of these activities on symptoms of depression. It is proposed in the
present dissertation that an exercise program may lead to an alteration in response style.
Exercising individuals may spend less time in rumination and, instead, engage in

distracting activities as a means to elevate their mood.

Mood Elevation Following Acute Bouts of Exercise

While it has not been formally proposed as a potential mechanism for the
antidepressant effects of exercise, it is conceivable that transient mood elevation
following repeated acute bouts of exercise might be associated with reductions in the
symptoms of clinical depression. Although exercise has been shown to be effective in
alleviating the symptoms of more severe mood disorders such as anxiety and depression
(Craft & Landers, 1998; Landers & Petruzzello, 1994), there is also a p0pular notion that
exercise can have a positive inﬂuence on normal variations in mood as well. The
relationship of transient mood enhancement with clinical depression has not been
extensively examined in the exercise science literature, but the ability of exercise to
enhance mood in the general population has long been a popular area of investigation.

Researchers were initially interested in the ability of exercise to improve negative
mood states. Findings suggest that exercise can reduce negative aspects of mood (Berger
& Owen, 1988; Fremont & Craighead, 1987; Markoulakis & Zervas, 1993; McGowan,
Talton, & Thompson, 1996; McGowan & Pierce, 1991; Young, 1996). Further, exercise
can enhance the positive aspects of mood as well (Arent, Landers, & Etnier, 2001;
McIntyre, Watson, & Cunningham, 1990; Petruzzello, Jones, & Tate, 1997; Steptoe &
Cox, 1988; Tate & Petruzzello, 1995).

Several variables such as gender, type of exercise, duration, intensity, and
frequency of exercise have been examined as potential moderators of the effect of
exercise on mood. Exercise can elevate mood for both males and females but the effects
may be larger for women (Berger, Owen, Motl, & Parks, 1998; Roth, 1989; Stephens,

1988). Stephens (1988) suggests that this relationship may result from the fact that

women are generally more sedentary then men and therefore, likely have more to gain
from the exercise bout. Many different types of exercise have been associated with
enhanced mood (Berger & Owen, 1993; Blumenthal et al., 1982; Fremont & Craighead,
1987; Hartz, Wallace, & Cayton, 1982; Maroulakis & Zervas, 1993; McGowan et al.,
1993; McGowan & Pierce, 1991; McGowan et al., 1996). As for the optimal duration of
the exercise bout, the literature remains unclear (Berger & Owen, 1983; Flory & Holmes,
1991; Hobson & Rejeski, 1993; Thayer et al., 1993). The current general
recommendations are 20-30 min bouts of exercise (Hansen, Stevens, & Coast, 2001).
Although the ﬁndings have been somewhat inconsistent, research suggests that moderate
intensity exercise is most beneﬁcial for improving mood (Berger & Owen, 1998; Hardy
& Rejeski, 1989; McGowan et al., 1996; Moses et al., 1989; Parﬁtt, Eston, & Connolly,
1996; Steptoe & Cox, 1988). Finally, the optimal frequency of exercise also remains
unknown as mood enhancement has been associated with as few as one bout of exercise
per week (Hartz, et al., 1982; Roth, 1989; Steptoe, Kearsley, & Walters, 1993; Wilson et
aL,1980)

Much of the aforementioned research has examined the relationship between
chronic exercise and mood. Acute exercise, however, has also been studied and the
positive effects of acute exercise on mood have been noted at 15 min, 30 min, and even
24 hr following the exercise bout (Dyer & Crouch, 1988; Hansen et al., 2001; Maroulakis
& Zervas, 1993; McMillan et al., 1993; Steptoe et al., 1993). Little is known about the
mood enhancing effects of acute exercise in individuals suffering from mental health
problems. Two studies were located that examined the relationship between exercise and

mood in depressed individuals involved in chronic exercise programs (Fremont &

Craighead, 1987; Hartz et al., 1982). The ﬁndings of these two studies were inconclusive
with some participants experiencing enhanced mood and others failing to beneﬁt from the
exercise intervention. Unfortunately, no studies were located that examined the effects of
an acute bout of exercise on mood in clinically depressed individuals.

The opponent process theory (Solomon, 1980) can provide a theoretical
foundation on which one could make predictions regarding the mood enhancing effects of
acute exercise. This theory states that as an individual engages in an arousing activity
there are two opposing processes that are occurring simultaneously. The predominate
response is termed the “A” state. This is the stimulating or arousing response and is
initially quite strong and weakens across time. The opposing response is termed the “B”
state. This response is in opposition to the “A” state and attempts to return the body to
homeostasis. The “B” state is initially weak but strengthens across time. With continued
exposure to the arousing activity, the “A” state weakens and the “B” state strengthens.
With exercise, we could predict that when ﬁrst beginning an exercise program the “A”
state is initially unpleasant. For example, the individual may feel fatigued, have sore
muscles, feel short of breath, etc. The “B” state, conversely, is in opposition to the
negative feelings of the “A” state, is shorter lasting initially, and is generally pleasant (i.e.
relaxation, stress reduction). Over time, we would expect that the “A” state would
shorten, leading to less negative feelings associated with exercise. The “B” state should
lengthen, leading to enhanced and longer lasting feelings of improved mood.

Only one study was located that examined this theory within the conﬁnes of acute
exercise (Petruzzello et al., 1991). The authors found partial support for the theory in that

post exercise affective states were more positive than affective states during exercise.

10

However, prior exposure to exercise did not moderate the affect as anticipated. This
theory should be investigated further with those suffering from clinical depression.
Researchers and clinicians need to understand at what point in a chronic exercise
intervention individuals may begin to feel mood elevation after each acute bout of
exercise and how long such mood elevation is likely to last.

Therefore, the purpose of this study was to explore two research questions. First,
two previously proposed mechanisms for the antidepressant effects of exercise, self-
efﬁcacy and distraction, were examined. The relationships between self-efficacy,
response style (rumination and distraction), exercise, and clinical depression were
studied. The following hypotheses were proposed:

1. A chronic exercise intervention is associated with a reduction in the symptoms of
clinical depression.

2. Participants in an exercise training intervention will report increased levels of coping
self-efﬁcacy.

3. Depressed individuals who engage in a chronic exercise intervention will report a
reduced tendency to ruminate on their depression and an increased use of distraction
across the 9-week intervention.

4. Obtained levels of coping self-efﬁcacy,irumination, and distraction will be related to
current levels of depression among exercise group participants.

The second research question was exploratory in nature. I examined whether or
not depressed participants experienced enhanced mood following acute exercise bouts.

Furthermore, the length of mood enhancement following acute exercise bouts, and the

11

potential relationship between this transient elevation in mood and symptoms of

depression was explored.

12

CHAPTER TWO
Review of the Literature

Clinical depression affects millions of Americans each year. It is estimated that
18 million adults or roughly 9.5% of the United States (U .S.) population aged 18 years
and older will experience a depressive episode each year (National Institutes of Mental
Health, 2001). Depression is twice as prevalent in females as males and the risk of a
recurrence can be as high as 50-90% (Preskom, 1999; Stahl, 1996). This disease is also
very costly to the US. economic system. Each year, over 40 billion dollars is spent on
lost productivity and medical treatment related to depression (Zerihun, 2001). A recent
study examining trends in the treatment of depression has shown that between the years
of 1987 and 1997 the rate of outpatient treatment for depression in the US. tripled and
that health care costs related to this illness continued to rise (Olfson, Marcus, Druss,
Elinson, Tanielian, & Pincus, 2002). With depression ranked as the fourth leading cause
of disability worldwide (Murray & Lopez, 1996), it appears that this disorder will
continue to effect millions of individuals and economically drain the health care system.

Traditional treatments for clinical depression have primarily included
psychotherapy and pharmacological interventions (Johnson & Miller, 1994; Preskom,
1999). Unfortunately, these therapies are often ineffective and, for some, also have
extremely adverse side effects (Byrne & Byrne, 1993; Leith, 1994). For example,
psychotherapy is often very timely and costly (Mutrie, 2000). Pharmacological
interventions can pose a variety of negative side effects including hypertension,
dizziness, dry mouth, blurred vision, sedation, weight gain, agitation, and sexual

dysfunction (Leith, 1994; Raglin, 1990; Stahl, 1996). Furthermore, health care changes

13

in the US. have led to time constraints for therapy and limits in payment for mental
health services (Mirin & Sederer, 1994). Therefore, practitioners and researchers are
investigating possible alternatives in the treatment of this disorder.

Exercise has been proposed as one plausible adjunct or alternative to the
traditional treatments for depression. There have been numerous research studies that
have examined the relationship of exercise with clinical depression. For example,
researchers have conducted cross-sectional studies comparing the physical activity and
physical capacity levels of depressed and non-depressed individuals (Martinsen, Medhus,
& Sandvik, 1985; Martinsen, Strand, Paulsson, & Kaggesstad, 1989; Morgan, 1969,
1970). Results indicated that depressed individuals were more physically sedentary than
the non-depressed, that physical work capacity (PWC) was lower in depressed
individuals, and that the PWC of depressed adults was only 80-90% of predicted norm
values. Further, PWC demonstrated a signiﬁcant negative correlation with severity of
depression. While these early studies did not address the directional nature of the
relationship between physical capacity and depression, researchers have continued to
investigate the ways in which physical activity is related to depression.

The efﬁcacy of exercise to alleviate depression has also been examined. The
majority of studies have shown that exercise is related to a reduction in depression and
that exercise appears effective for both males and females (Brown, et al., 1992; Dimeo,
Baurer, Varahm, Proest, & Halter, 2001; Doyne, Chambless, & Beutler, 1983; McNeil,
LeBlanc, & Joyner, 1991; Veale et al., 1992). The types of exercise utilized with
depressed patients have also been studied in an attempt to determine if certain kinds of

exercise are more effective in alleviating depression (Doyne et al., 1987; Martinsen,

l4

Hoffart, & Solberg, 1989; Sing, Clements, & F iatarone, 1997). Most often, aerobic
activities (such as running) have been compared to strength training activities, which are
primarily non-aerobic in nature. Both forms of exercise have been shown to be
beneﬁcial. Finally, researchers have compared exercise to more traditional treatments
such as psychotherapy, behavioral modiﬁcation, and medication (Babyak et al., 2000;
Blumenthal et al., 1999; Greist et al., 1979; Kleine et al., 1985). The results of these
studies are very encouraging and indicate that exercise is as effective as most traditional
therapies such as psychotherapy and behavioral interventions. The recent work by
Blumenthal and colleagues (Babyak et al., 2000; Blumenthal et al., 1999) suggests that
exercise may be as effective as some antidepressant medications. In their studies,
medication worked more quickly to reduce depression but exercise was as effective as
medication by the end of the 16-week exercise program.

While the vast majority of the evidence from these studies provides support for
the antidepressant effects of chronic exercise, the research in this area has been criticized
for suffering from a variety of methodological flaws. (Byrne & Byrne, 1993; Gleser &
Mendelberg, 1990; Martinsen, 1990, 1993, 1994). For example, studies have failed to
utilize random assignment and control groups and have used very small sample sizes
(Blue, 1979; Doyne, Chambless, & Beutler, 1983; Hartz, Wallace, & Clayton, 1982).
Further, participants have often been college students with depressed affect or post
myocardial infarction patients, rather than individuals suffering from diagnosed clinical
depression (Jasnowski, Holmes, & Banks, 1988; Kavanaugh, Shephard, Tuck, & Qureshi,
1977; McCann & Holmes, 1984; Sharp & Reilley, 1975; Stem & Cleary, 1981). Finally,

many of the studies have failed to report exercise protocols or have done a poor job in

15

actually achieving ﬁtness gains with aerobic activities (Brown et al., 1992; Doyne et al.,
1987; McNeil, LeBlanc, & Joyner, 1991).

Therefore, in an attempt to understand the overall pattern of the research ﬁndings
and to investigate variables that may potentially moderate the effect of exercise on
depression, researchers have synthesized the results of the primary studies in this area
(Craft & Landers, 1998; North, McCullagh, & Tran, 1990). Results of these meta-
analyses indicate that chronic exercise is effective in alleviating symptoms of depression.
In the Craft and Landers (1998) study, the overall effect size was reported as -0.72.
North and colleagues (1990) reported a smaller overall effect size of -0.53, but when
considering only studies that used clinical samples the effect increased to -0.94.
Interestingly, these studies found that duration, intensity, frequency, and mode of
exercise did not moderate the relationship between exercise and depression. Length of
exercise program did moderate the effect, with interventions of 9 weeks or longer being
most effective. Other variables such as gender, age, and initial severity of depression
were also considered. Findings were very encouraging with exercise effective for both
males and females of all ages as well as those who are initially more severely depressed.
Therefore, in light of this additional meta-analytic support, researchers have begun to
recommend that depressed individuals should adopt physically active lifestyles to help
manage their symptoms (Craft & Landers, 1998; Fox, 1999; Mutrie, 2000).

While the research is relatively clear that chronic exercise helps alleviate
symptoms of depression, the mechanisms for the antidepressant effects of exercise

remain unknown. Several physiological and psychological mechanisms have been

16

proposed for the antidepressant effects of exercise. However, our knowledge remains
limited regarding the ways in which exercise reduces symptoms of depression.
Mechanisms for the Antidepresgnt Effects of Exercise

The overwhelming support for exercise as an effective means to alleviate
depression has led some researchers to examine potential causal links between exercise
and depression. For example, Mutrie (2000) suggests that exercise is not only related to

reductions in depression but that it causes a reduction in depression. Mutrie bases her

 

determination of this causal link on epidemiological principles (Hill, 1965) such as
strength of association, consistency, temporal sequence, biological plausibility, and
experimental evidence. Landers and Arent (2001) however, argue that in order for a
causal association to be met, the following must also be demonstrated: a dose-response
relationship, coherence, and speciﬁcity. Landers and Arent (2001) suggest that there is
little evidence for either a dose-response relationship or speciﬁcity of effect. As for
coherence, (“the idea that possible mechanisms do not conflict with what is known about
the natural history and biology of the disease,” p. 755), the research to date has not
extensively examined the plausible mechanisms suggested in the literature. Therefore, it
appears that a better understanding of the mechanisms behind the antidepressant effects
of exercise would not only provide additional insight into a possible causal association,
but should also be helpful in the future use of exercise as an adjunct therapy. Until
researchers and clinicians understand how exercise leads to a reduction in depression it
will be difﬁcult to further our attempts to effectively utilize exercise with clinically

depressed patients.

17

Several credible physiological and psychological mechanisms have been
described such as the thermogenic hypothesis, the endorphin hypothesis, the monoamine
hypothesis, the distraction hypothesis, and the enhancement of self-esteem and self-
efﬁcacy (Bandura, 1997; Dishman, 1997; Gleser & Mendelberg, 1990; Leith, 1994;
Martinsen, 1990; Ransford, 1982; Simons, McGowan, Epstein, Kupfer, & Robertson,
1985). However, there is little research evidence to either support or reﬁrte most of these
theories. Therefore, studies are needed that examine these potential physiological and
psychological mechanisms (Dunn, Trivedi, & O’Neil, 2001; Fox, 1999; Landers & Arent,
2001; Leith, 1994).

Physiological Mechanisms

The three physiological mechanisms mentioned above (i.e. thermogenic,
endorphin, and monoamine hypotheses) have been the primary physiological
explanations proposed for the antidepressant effects of exercise. The thermogenic
hypothesis suggests that a rise in body core temperature following exercise is responsible
for the reduction in symptoms of depression. DeVries (1981) explains that increases in
temperature of speciﬁc brain regions, such as the brain stem, can lead to an overall
feeling of relaxation and reductions in muscular tension. While this idea of increased
body temperature has been proposed as a mechanism in the relationship between exercise
and depression, the research conducted on the thermogenic hypothesis has only examined
the effect of exercise on feelings of anxiety (DeVries, 1968; Morgan, 1988; Raglin &
Morgan, 1985).

The endorphin hypothesis predicts that exercise has a positive effect on

depression due to an increased release of beta-endorphins following exercise.

18

Endorphins are related to a positive mood and an overall enhanced sense of well-being.
This line of research has not been without criticism. The debate remains as to whether
plasma endorphins reflect endorphin activity in the brain. However, some (Johnsgard,
1989; Morgan, 1985) have argued that even if peripheral endorphin levels are not
reﬂective of brain chemistry they could still be associated with a change in mood or
feelings of depression. Several studies have shown increases in plasma endorphins
following acute and chronic exercise (e.g., Bortz, Angwin, & Mefford, 1981; Carr et al.,
1981; Farrell, Gates, & Maksud, 1982), however, it remains unclear if these elevations in
plasma endorphins are directly linked to a reduction in depression.

The monoamine hypothesis appears to be the most promising of the proposed
physiological mechanisms. This hypothesis predicts that exercise leads to an increase in
brain neurotransmitters (i.e. serotonin, dopamine, norepinephrine) that are related to
symptoms of depression. These neurotransmitters increase in plasma and urine following
' exercise (Ebert, Post, & Goodwin, 1972; Post, Kotin, Goodwin, & Gordin, 1973; Tang,
Stancer, Takahashi, Shephard, & Warsh, 1981). However, whether exercise leads to an
increase in neurotransmitters in the brain remains unknown. Animal studies suggest that
exercise increases chemicals such as serotonin and norepinephrine in various brain
regions (Dishman, 1997; Dunn, Reigle, Youngstedt, Armstrong, & Dishman, 1996;
Jacobs, 1994 ). However, in humans this has not been studied.

Therefore, while several physiological mechanisms remain plausible,
methodological difﬁculties have prevented this line of research from advancing in
humans. Martinsen (1987) discusses how testing biochemical hypotheses are often

difficult in humans due to the invasive procedures necessary to obtain samples (i.e. blood

19

samples, cerebrospinal ﬂuid samples). Further, biochemical samples obtained ﬁ'om
blood or other body ﬂuids may not directly reﬂect the activity of these compounds in the
brain (Dishman, 1997). Hopefully, with the advent of new neuroimaging techniques,
future researchers can examine whether exercise leads to the neurochemical changes in
the brain predicted by these physiological hypotheses.
Psychological Mechanisms

Several psychological mechanisms have also been proposed. As was the case
with the physiological mechanisms, many of these theories have not been tested as
explanations of the beneﬁts of exercise for depression. Two psychological theories that
have received attention in the literature and warrant further examination are the self-
efﬁcacy hypothesis and the distraction hypothesis.
Self-Efﬁcacy

The enhancement of self-efﬁcacy has been proposed as one mechanism by which
exercise may help alleviate symptoms of clinical depression. Bandura’s (1977, 1997)
conceptualization of self-efﬁcacy is derived from social cognitive theory and is deﬁned
as “a generative capability in which cognitive, social, emotional, and behavioral sub-
skills must be organized and effectively orchestrated to serve innumerable purposes”
(Bandura, 1997, pp. 36-37). Self-efficacy refers to the belief that one possesses the
necessary skills to complete a task as well as the conﬁdence that the task can actually be
completed with the desired outcome obtained. Once efficacy beliefs have been formed,
they will direct choice of behavior, goals that are chosen, persistence at a task, motivation
and effort, expectations of success, and how one responds affectively (Bandura, 1997).

Efficacy beliefs can vary in generality and strength. For example, a person may feel

20

efﬁcacious across many different types of activities or may have high self-efﬁcacy for
only a few speciﬁc activities. Furthermore, an individual may have very strong efﬁcacy
beliefs that will persist in the face of obstacles and failures or efﬁcacy beliefs may be
rather weak and easily subject to change.

Efﬁcacy to manage and direct oneself is also an important part of human
functioning. Bandura (1997) contends that the individual must not only be able to
regulate goal directed behaviors but that healthy people are also able to use regulatory
strategies for their thoughts, feelings, and emotions. This idea of self-regulation has led
to the investigation of the concept of coping self-efﬁcacy. When faced with a stressful
situation, people’s beliefs about their ability to control the situation and regulate their
response to the situation is a primary determinant of how they will respond. At times, a
low sense of self-control can be more problematic than perceived inability to control the
environment (Bandura, 1997). This idea of efﬁcacy to regulate behavior or “cope”
becomes very important when discussing those who suffer from mental illness.

Coping self-efﬁcacy and its relationship with mental health has primarily been
studied within the context of anxiety. Those with high coping efﬁcacy have less anxiety
during surgical procedures and need less pain medication after surgery than those with
low efﬁcacy (Bastone & Kerns, 1995; Litt, Nye, & Shafer, 1995). Individuals with
anxiety disorders were also shown to have fewer catastrophic thoughts and were less
likely to have a panic attack after undergoing interventions designed to enhance their
coping self-efﬁcacy (Sanderson, Rapee, & Barlow, 1989). Further, women with high
coping efficacy have higher cognitive control efﬁcacy, decreased perceived vulnerability

to threat, and lower levels of anxiety compared to women with low efﬁcacy (Ozer &

21

Bandura, 1990). Finally, stressful situations elicit decreased blood pressure and cardiac
reactivity and lower levels of catecholamine secretion in study participants who have
high coping efﬁcacy (Bandura, Taylor, Williams, Mefford, & Barchas, 1985; Gerin, Litt,
Deich, & Pickering, 1995). C0ping self-efﬁcacy is an important part of optimal
functioning because perceived inability to cope with potential threats or stressful
situations leads people to approach such situations anxiously and with a low sense of
efﬁcacy that they will perform the behavior successfully.

Bandura (1997), utilizing self-efﬁcacy theory, describes how depressed peOple
often feel inefficacious to bring about positive desired outcomes in their lives and have
low efﬁcacy to cope with the symptoms of their depression. This can lead to negative
self-evaluation, negative ruminations, and faulty styles of thinking. Individuals who have
low self-efficacy often blame themselves for negative life events and this negative
explanatory style can worsen and prolong their depression (Peterson & Seligman, 1984).
Another way in which low efﬁcacy can contribute to depression is through the perceived
inability to deal with negative thoughts and ruminations. Those with low efficacy to stop
or restructure negative thoughts have have higher levels of depression (Kavanagh &
Wilson, 1989). Furthermore, a low sense of efﬁcacy to develop and maintain positive,
satisfying social relationships can lead to and prolong bouts of depression (Bandura,
Pastorelli, Barbaranelli, & Caprara, 1999; Holahan & Holahan, 1987).

Several different factors inﬂuence the development of efficacy beliefs. Four
primary sources of efﬁcacy information have been identiﬁed (Bandura, 1997). The best
source of efficacy information appears to come from mastery experiences. When a

person can repeatedly derive a course of action, follow a plan, and meet the desired

22

outcome in the face of changing situations and obstacles then they are likely to feel
highly efﬁcacious. On the contrary, repeated failures at such attempts to navigate
through life can lead to decreased feelings of self-efficacy. A second source of efficacy
information is vicarious experience. Modeling the behaviors of others who are successﬁrl
can lead to heightened efficacy beliefs. Seeing others like oneself make successful
attempts at some desired behavior or demonstrate effective coping can raise one’s own
efficacy beliefs. Verbal persuasion also has some power to alter efﬁcacy beliefs.
Encouragement and feedback from an inﬂuential, credible person can enhance feelings of
efficacy. Finally, physiological and affective states provide efﬁcacy information. If a
stressﬁrl situation elicits high levels of arousal and negative affect, the person is likely to
feel inefﬁcacious to obtain the desired outcome.

1 am suggesting here that exercise may provide an effective mode through which
self-efficacy can be enhanced based primarily on its ability to provide the individual with
a meaningful mastery experience. According to Bandura (1997), in order for an
intervention to lead to enhanced coping self-efﬁcacy it must teach the individual how to
self-monitor behaviors, set goals, and utilize social support to maintain the desired
behaviors. Further, Zeiss and colleagues (Zeiss, Lewinsohn, & Munoz, 1979) suggest
that a variety of therapies can be beneﬁcial in the treatment of depression if they provide
a mastery experience that enhances the beliefs of patients that they can control their
behavior, teach patients some skill perceived as important to them, encourage patients to
utilize the skill to achieve some personal goal, and contribute the reduction in depressive
symptoms to the patient’s mastery and use of the skills. It is easy to conceive that a

chronic exercise program could meet each of the qualiﬁcations mentioned. Learning how

23

to monitor exercise behaviors, set short and long term exercise goals, and positive
support from the exercise instructor and signiﬁcant others can all contribute to feelings of
mastery. Therefore, perhaps the antidepressant properties of exercise are related to an
enhanced sense of efﬁcacy that results from a mastery experience.

As mentioned previously, mastery experiences are thought to have the most
powerful inﬂuence on perceptions of efﬁcacy. However, vicarious experience, verbal
persuasion, and changes in physiological and affective states are also components of an
exercise program that may inﬂuence efﬁcacy beliefs. For example, seeing others learn to
engage in and enjoy exercise may provide an opportunity for modeling. Further, positive
feedback and encouragement from the exercise leader can be a form of verbal persuasion
that aids in the development of efficacy beliefs. Finally, as one learns to exercise and
becomes more physically ﬁt, physiological states (i.e. increased heart rate, fatigue) tend
to become less negative and affective responses to exercise are likely to be more positive.
Therefore, the realization that exercise is becoming easier and less painful can also
promote an enhanced sense of self-efﬁcacy. Thus, engaging in an exercise program and
the skills learned in an exercise setting may lead to an increase in feelings of self-
efﬁcacy.

Research examining the association between physical activity and self-efﬁcacy
has predominately focused on the enhancement of physical self-efﬁcacy and efﬁcacy to
regulate exercise behaviors. Such studies have examined the relationship between an
individual’s perceived efficacy to exercise and the amount of physical activity in which
he or she engages, ways to increase a person’s conﬁdence in his or her ability to engage

in an exercise program, and strategies to increase self-regulatory behaviors when

24

confronted with perceived barriers such as a lack of time, fatigue, etc. (Beniamini,
Rubenstein, Zaichkowksy, & Crim, 1997; Ewart, Stewart, Gillilan, & Kelemen, 1986;
McAuley, 1992; McAuley & Coumeya, 1992; McAuley, Lox, & Duncan, 1993). The
relationship between exercise and self-efﬁcacy in the clinically depressed has not been
studied extensively. The ﬁndings of the few studies that have examined this relationship
have been equivocal as to whether exercise leads to an enhancement of generalized
feelings of efﬁcacy and have failed to examine whether involvement in an exercise
program can promote coping self-efﬁcacy speciﬁc to one’s depression (Brown, Welsh,
Labbe, Vitulli, & Kulkarni, 1992; Singh, Clements, & Fiatarone, 1997). Enhanced
feelings of coping have been associated with exercise participation in anxious adults
(Steptoe, Edwards, Moses, & Mathews, 1989), however, as mentioned previously, this
relationship has not been examined with the clinically depressed. Therefore, the role that
exercise can play in augmenting the coping self-efﬁcacy of depressed patients needs
further examination.
Distraction

The concept of distraction has also been proposed as a possible explanation for
the antidepressant effects of exercise. This hypothesis suggests that physical activity
serves as a distraction from worries and depressing thoughts. A theory of depression that
is conceptually related to this potential mechanism is the response styles theory (Nolen-
Hoeksema, 1991). This theory discusses two different dispositional ways in which
individuals may respond to feelings of depression and how these differing responses can
affect the severity and length of a depressive episode. Rumination is a response style that

involves the tendency to passively and repeatedly focus on one’s negative feelings and

25

the consequences of those feelings. Distraction refers to a response style in which the
one busies herself in an engaging activity (i.e. a hobby, work) in an attempt to focus on
something other than the depressed mood.

Rumination is thought to inﬂuence the course of depression in at least four ways.
First, rumination may lead to negative thoughts and attributions about the self, past,
present, and future which can contribute to a continued depressed mood (Lyubomirsky &
Nolen-Hoeksema, 1995). Second, rumination may interfere with the initiation of
problem—solving behaviors. Individuals who focus on their negative thoughts rather than
engage in activities to solve their problems are at risk for prolonged bouts of depression
(Nolen-Hoeksema, Parker, & Larson, 1994). Third, those who ruminate about their
depression may not engage in behaviors that provide the opportunity for positive
reinforcement and an enhanced sense of control (Lyubomirsky & Nolen-Hoeksema,
1993). Without such opportunities, feelings of helplessness, negative evaluations of self,
lowered expectancies for the ﬁrture, and a lack of motivation to meet new challenges may
prevail (Nolen-Hoeksema, 1991). Fourth, the tendency to ruminate often alienates
sources of social support (such as family and friends) who may grow tired of hearing the
individual contemplate his depression (Nolen-Hoeksema & Davis, 1999).

The use of distracting activities, however, has been shown to have a more positive
inﬂuence on the management of depression. Study participants who engaged in
distracting activities showed a greater reduction in their depression than did those
assigned to ruminating activities (Morrow & Nolen-Hoeksema, 1990; Nolen-Hoeksema
& Morrow, 1991). Further, patients seeking treatment for mood disorders who were

willing to engage in distracting activities as part of cognitive-behavioral therapy were less

26

depressed at follow-up than those who did not engage in distracting activities (Burns &
Nolen-Hoeksema, 1991). Distraction often leads to enhanced mood. This temporary
elevation of mood allows for more effective problem solving related to one’s depression
(Nolen-Hoeksema, Morrow, & Fredrickson, 1993). Finally, depressed people who
engage in distracting activities to cope with their symptoms are less likely to engage in
risky or violent behaviors as compared to those who ruminate on their depression (Nolen-
Hoeksema & Morrow, 1991).

Research related to response styles theory indicates that women spend more time
engaging in rumination than men, that men tend to use distraction more than women, and
that those with a ruminative response style generally have more severe and longer lasting
episodes of depression than those who use distraction as a response style (Just & Alloy,
1997; Morrow & Nolen-Hoeksema, 1990; Nolen-Hoeksema & Morrow, 1991; Nolen-
Hoeksema et al., 1993). Therefore, based on the current research, a distraction response
style appears to be associated with a more positive outcome for individuals who are
depressed (Nolen-Hoeksema, 1998, 1991).

Nolen-Hoeksema (1991) cautions that not all activities are distracting and that
rumination can still occur in spite of involvement in many activities. To ensure that a
particular activity is an effective distractor, it must engage the individual and have a high
probability of providing opportunities for positive reinforcement (Nolen-Hoeksema,
1991). The very nature of exercise makes it a potentially distracting activity worthy of
investigation. During a workout, exercise related goals and attending to somatic changes
such as breathing, heart rate, fatigue, and sore muscles often become the focus of

attention (Leith, 1994). Furthermore, exercise offers the opportunity for positive

27

reinforcement as training goals are met, daily workouts become less painﬁrl and
fatiguing, and signiﬁcant others reward the individual for taking a proactive role in the
management of her symptoms. Therefore, the antidepressant effects of exercise may
result from the ability of exercise to provide periodic distraction from negative thoughts
and feelings of depression. As mentioned previously, this temporary attenuation of
depressed mood may allow for more effective engagement in problem-solving behaviors.

Response styles theory has not yet been tested with depressed people who engage
in an exercise program as a distracting activity. Exercise has been compared to other
distracting activities such as relaxation, assertiveness training, health education, and
social contact (Doyne et al., 1983; Klein et al., 1985; McNeil, LeBlanc, & Joyner, 1991;
Singh, Clements, & F iatarone, 1997). Results have been inconclusive with exercise more
effective than some activities and similar to others in its ability to aid in the reduction of
depression. This line of research, however, has only examined the effect of these
activities on symptoms of depression. It is proposed here that an exercise program may
lead to a behavioral alteration in response style. Exercising participants may learn to
spend less time in rumination and, instead, engage in distracting activities as a means to
elevate mood. Therefore, research is needed to determine if physical activity reduces the
tendency to ruminate and enhances the tendency to utilize distracting activities as a way
of dealing with depression.
Mood ElevaLion Following Acute Bouts of Exercise

While it has not been formally proposed as a potential mechanism for the
antidepressant effects of exercise, it is conceivable that transient mood elevation

following repeated acute bouts of exercise might be associated with reductions in the

28

symptoms of clinical depression. It is known that people normally experience a wide
range of moods such as happiness, sadness, anger, distress, fear, enthusiasm, etc. While
exercise has been shown to be effective in managing the symptoms of more severe mood
disorders such as anxiety and depression (Craft & Landers, 1998; Landers & Petruzzello,
1994), there is also a popular notion that exercise can have a positive inﬂuence on normal
variations in mood. While the relationship of transient mood enhancement with clinical
depression has not been examined in the exercise science literature, the ability of exercise
to enhance mood in the general population has long been a popular area of investigation.
The relationship between exercise and mood has historically been examined by
utilizing self-report inventories such as the Proﬁle of Mood States (POMS), the Mood
Adjective Checklist, and the Positive Affect and Negative Affect Schedule (PAN AS).
These inventories assess both positive (i.e. excited, inspired, vigor) and negative (i.e.
tension, fatigue, guilt) dimensions of mood. Researchers were initially interested in the
ability of exercise to improve negative mood states and have predominantly utilized pre-
test/post-test designs to examine changes in mood following exercise. Findings indicate
that exercise can reduce negative aspects of mood such as anger, tension, depression,
anxiety, fatigue, and confusion (Berger & Owen, 1988; Fremont & Craighead, 1987;
Markoulakis & Zervas, 1993; McGowan, Talton, & Thompson, 1996; McGowan &
Pierce, 1991; Yeung, 1996). Fewer studies have examined the effects of exercise on the
positive aspects of mood, but it appears that exercise also enhances positive emotions like
vigor, excitement, liveliness (Arent, Landers, & Etnier, 2001; McIntyre, Watson, &
Cunningham, 1990; Petruzzello, Jones, & Tate, 1997; Steptoe & Cox, 1988; Tate &

Petruzzello, 1995).

29

Several variables such as gender, type of exercise, duration, intensity, and
frequency of exercise have been considered as potential moderators of the effect of
exercise on mood. Studies examining gender differences have reported mixed results.
While exercise can elevate mood for both males and females, the effects may be larger
for women (Berger, Owen, Motl, & Parks, 1998; Roth, 1989; Stephens, 1988).
Furthermore, several different kinds of exercise have been investigated such as walking,
running, swimming, cycling, aerobic dance, karate, and strength training (Berger &
Owen, 1993; Blumenthal et al., 1982; Fremont & Craighead, 1987; Hartz, Wallace, &
Cayton, 1982; Maroulakis & Zervas, 1993; McGowan et al., 1993; McGowan & Pierce,
1991; McGowan et al., 1996). Each of these exercises were associated with enhanced
mood and one type did not have a distinct advantage over any other type.

As for the optimal duration of the exercise bout, the literature remains unclear.
Studies have been conducted utilizing different durations of exercise (i.e. Berger &
Owen, 1983; Flory & Holmes, 1991; Thayer et al., 1993), however, there are fewer
studies that have actually compared varying durations of exercise and their effects on
mood (i.e. Hanson, Stevens, & Coast, 2001; Hobson & Rejeski, 1993). Hansen, Stevens,
and Coast (2001) recently compared the mood enhancing effects of 10, 20, and 30 min of
exercise. They reported that mood was improved following as little as 10 min of exercise
with continued improvement through 20 min. There were no additional beneﬁts to mood
with 30 min of exercise. Therefore, the current general recommendations of 20 - 30 min
of exercise appear supported but more information is needed regarding longer bouts of

exercise.

30

Intensity of exercise does seem to play an important roleiin the relationship
between mood and exercise. Moderate intensity exercise appears most beneﬁcial for
improving mood and mood tends to become more negative as exercise intensity increases
(Berger & Owen, 1998; Hardy & Rejeski, 1989; McGowan et al., 1996; Moses et al.,
1989; Parﬁtt, Eston, & Connolly, 1996; Steptoe & Cox, 1988). Various frequencies of
exercise have also been considered with as few as one exercise bout per week and as
many as seven bouts per week associated with enhanced mood (Hartz, et al., 1982; Roth,
1989; Steptoe, Kearsley, & Walters, 1993; Wilson et al., 1980). It remains unknown
what exercise frequency is associated with the largest improvements in mood.

Many of the studies examining this relationship have utilized chronic exercise
programs (i.e. Berger & Owen, 1983; DiLorenzo et al., 1999; Fremont & Craighead,
1987; Steptoe et al., 1993; Wilson et al., 1980). .Acute bouts of exercise, however, have
also been investigated. Single bouts of exercise can also have a positive effect on mood
(Hansen et al., 2001; Kennedy & Newton, 1997; McGowan, Pierce, & Jordan, 1991;
McGowan et al., 1996). Elevated mood has been noted at 15 min, 30 min, and even 24 hr
following an exercise bout, but more information is needed (Dyer & Crouch, 1988;
Hansen et al., 2001; Maroulakis & Zervas, 1993; McMillan et al., 1993; Steptoe et al.,
1993). Further, the potential interactions of exercise intensity, exercise duration, and
length of mood enhancement warrant continued investigation (Landers & Arent, 2001).

The overwhelming majority of studies in this area have been conducted with
college students or healthy adults as participants. Little is known about the mood
enhancing effects of exercise in those suffering from mental health problems. Two

studies were located that examined this relationship in depressed individuals involved in

31

chronic exercise programs (Fremont & Craighead, 1987; Hartz et al., 1982). Fremont
and Craighead (1987) reported improvements in depression, confusion, anxiety, anger,
fatigue, and vigor following a 10-week running intervention. Mood enhancement was
reported as early as 3 weeks after the initiation of the intervention. Hartz et al. (1982),
however, found that exercise had mood-elevating effects for two of their participants but
not for the participant group as a whole. No studies were located that examined the
effects of an acute bout of exercise on mood in clinically depressed patients.

The opponent process theory (Solomon, 1980) can provide a theoretical
foundation on which one could make predictions regarding the mood enhancing effects of
acute exercise. This theory states that as an individual engages in an arousing activity
there are two opposing processes that are occurring simultaneously. The predominate
response is termed the “A” state. This is the stimulating or arousing response and is
initially quite strong and weakens across time. The opposing response is termed the “B”
state. This response is in opposition to the “A” state and attempts to return the body to
homeostasis. The “B” state is initially weak but strengthens across time. With continued
exposure to the arousing activity, the “A” state weakens and the “B” state strengthens.
Using exercise as an example, we could predict that when initiating an exercise program
the “A” state is initially unpleasant. For example, the individual may feel fatigued, have
sore muscles, feel short of breath, etc. The “B” state, conversely, is in opposition to the
negative feelings of the “A” state, is shorter lasting initially, and is generally pleasant (i.e.
relaxation, stress reduction). Over time, we would expect that the “A” state would
shorten leading to less negative feelings associated with exercise and the “B” state would

lengthen leading to more enhanced longer lasting feelings of improved mood.

32

A study that has tested this theory within the conﬁnes of acute exercise was
conducted by Petruzzello and colleagues (Petruzzello et al., 1991). They found partial
support for the theory in that post exercise affective states were more positive than
affective states during exercise. However, prior exposure to exercise did not moderate
the affect as anticipated. This theory needs further examination with the clinically
depressed. It would be advantageous to researchers and clinicians to understand at what
point in a chronic exercise intervention individuals may begin to feel mood elevation
after each acute bout of exercise and how long such mood elevation is likely to last. In
addition, the potential relationship between such transient mood elevation and symptoms
of depression warrants exploration. Information of this sort will help clinicians when
educating depressed patients on the benefits of involvement in physical activity
programs.

To conclude, the current literature suggests that exercise is an effective adjunct
therapy in the treatment of clinical depression. Little is known, however, regarding the
ways in which exercise exerts its positive inﬂuence. Coping self-efﬁcacy, distraction,
and transient mood elevation have been proposed here as potential psychological
mechanisms for the antidepressant effects of exercise. However, experimental research is
needed to test the theories related to these suggested mechanisms. Gaining insight into
how exercise works to reduce symptoms of depression will not only further our scientiﬁc
knowledge but will also aid clinicians in the use of exercise as a treatment for those

suffering from clinical depression.

33

CHAPTER THREE
Method
Participants and Design

Prior to data collection, study approval was obtained from the Institutional
Review Board (See Appendix A). Further, participants in this study signed an informed
consent (See Appendix A). All women in this study were Caucasian and the average age
of the participants was 43.21 years (SD = 13.23).

Initially, an experimental design with random assignment of participants to study
groups was planned. All participants who met study inclusion criteria indicated their
desire to be in the exercise intervention group. Of the 24 women originally recruited into
the study, only 2 attended the ﬁrst study organizational meeting. Follow-up contact with
the other 22 women resulted in several women who were still willing to participate and
several women who indicated that they no longer desired to participate in the study. The
women expressed a variety of reasons for no longer wishing to participate such as a lack
of time, personal illness or illness of family members, unwillingness to drive to campus
twice per week, etc. These women were asked if they would be willing to be control
group members. Some of the women agreed to be in the control group and others
declined. Therefore, a non-equivalent control group design (quasi-experimental) was
utilized and these remaining participants were assigned to their choice of either the
control group or the exercise intervention group.

Subsequently, 10 women chose to participate in the control group and 11 women
chose the exercise intervention group. There were two women who dropped out of the

study, both in the exercise intervention group. These participants attended the ﬁrst

34

exercise session which consisted primarily of information regarding stretching,
monitoring heart rate, and familiarization with the exercise equipment. Neither of these
women returned to the study after this initial session. One participant stated that she was
too busy to take part in the study and the other woman elected to enter psychotherapy and
was therefore no longer eligible for the study. There were no further dropouts in either
the control or exercise group, leaving a total of 10 in the control group and 9 in the
exercise group.

All women were suffering from physician diagnosed clinical depression. Further,
participants were receiving pharmacological treatment for their depression (for at least 4
weeks prior to study entry) but were not receiving any additional psychological
treatments. Participants reported current episodes of depression lasting a mean of 17.47
months (SD = 28.75). Further, they had been taking their current medications for a mean
of 47.26 months (SD = 47.55). Participants were excluded if they were currently
involved in a regular exercise program (at least 3 days per week) or if they had been
involved in an exercise program at any time in the past year. Participants were also
excluded if they were concurrently suffering from another mental illness, were currently
undergoing any treatment other than pharmacological interventions for their depression,
or if they had any physical illness that would contraindicate exercise.

Participants were recruited from area physicians, advertisements placed in local
newspapers, and posted ﬂyers. Participants were informed that the purpose of the study
was to examine various treatments for clinical depression. All participants maintained
normal contact with their physician and continued pharmacological treatment during the

length of the study. Further, they were asked to report to the primary investigator any

35

change in antidepressant medication or medication dosage during the course of the study.
All participants who completed the 9-week study received $25.00 for their participation.
Questionnaires

Demographic. A questionnaire designed to gather demographic information was
administered to all participants. This questionnaire assessed a variety of variables such as
ethnicity, age of onset of ﬁrst depressive episode, number of hospitalizations for
depression, current antidepressant medication, current physical health problems, etc.
This questionnaire is contained in Appendix B.

Exercise program readiness questionnaire. Participants assigned to the exercise
intervention group completed this 10-item questionnaire. This inventory assessed health
status and risk factors (i.e. dizziness, history of heart attack, excessively overweight) that
would indicate the need for medical evaluation prior to beginning an exercise program.
Any woman who answered “yes” to at least one of the questions and all women over the
age of 40 were required to consult with their physician and provide a physician’s
signature indicating the participant’s suitability to engage in the moderate intensity
exercise program. This questionnaire is contained in Appendix C.

Beck Depression Inventory-II (Beck. Steer. & Brown. 1996 1. The BDI-II is a 21-
item self-report inventory designed to assess the behavioral and cognitive symptoms of
depression. Each item consists of several statements describing symptoms of depression.
The participant is asked to circle the statement that best describes her symptoms related
to that particular aspect of depression (i.e. feelings of guilt, changes in sleep). The
statements are numbered from “0” to “”,3 with higher numbers indicating more severe

symptoms. Scores for responses are summed to obtain an overall score. The overall sum

36

can range from 0 to 63, with higher scores indicating more severe depression. This
inventory has demonstrated acceptable internal consistency with the authors reporting
Cronbach’s alphas ranging from 92-93. Internal consistency for this study was
examined using Cronbach’s alpha and was deemed acceptable with or = .91. This
questionnaire is contained in Appendix D.

Depression Coping Self-Efﬁcacy Scale (Berraud, 2000). The DCSES is a 24-
item inventory designed to assess the coping self-efﬁcacy of depressed patients. The
inventory asks participants to rate their confidence in their ability to engage in a variety
of coping responses from 0 (not at all conﬁdent) to 10 (conﬁdent). The ratings for all
items are summed and a mean score is calculated. This inventory has demonstrated
acceptable internal consistency with the author reporting Cronbach alphas ranging ﬁ'om
.93-.96. Internal consistency was also acceptable for the DCSES in this study (or = .82).
This questionnaire is contained in Appendix E.

Responses Style Questionnaire (Nolen-Hoeksema& Morrow. 1991) This RSQ
assesses how an individual generally responds to feeling sad, down, or depressed. The
inventory has two subscales: the Ruminative Response Scale, which has 22 items and
assesses the tendency to respond to depression with self-focused behaviors and the
Distractive Response Scale, which has 11 items and assesses the tendency to engage in
distracting activities as a response to depression. The participant rates each response item
on a scale from 1 (almost never) to 4 (almost always). An overall score for each subscale
is obtained by summing responses. This inventory has demonstrated acceptable internal
consistency (Ruminative Response Scale: ct = .89 and Distractive Response Scale: on =

.80) (Nolen-Hoeksema & Morrow, 1991). In this study, the two subscales of the RSQ

37

were found to be internally consistent (Ruminative Response Scale, or = .88; Distractive
Response Scale, 0: = .71). This questionnaire is contained in Appendix F.

ﬁtjpg of Perceived Exertion (Borg. 1982. In an attempt to check the
participants’ perception of the exercise intensity and to determine if perceptions of effort
were related to enjoyment of the exercise bout, participants rated their perception of
effort exerted during exercise using Borg’s Rating of Perceived Exertion (RPE) scale.
This scale ranges from the numbers six to 20 with adjectives such as “very light”, “hard”,
and “very, very hard” anchored along the numerical scale. Participants were asked to
select the number that best described the intensity at which they felt theywere working.
This scale is contained in Appendix G.

W of epioyment of exercise. For each exercise session, participants rated
their level of enjoyment for the exercise bout on a 7-point Likert type scale. The scale
was anchored at -3 (not at all), 0 (undecided), and 3 (very much so). This inventory was
developed for the purposes of this study. This scale is contained in Appendix H.

Rating of mood. This inventory was also developed for the current study and
asked participants to rate their mood on a 7-point Likert type scale. This scale was also
anchored at -3 (sad, negative, down), 0 (neutral), and 3 (happy, positive, upbeat).
Participants rated their mood immediately prior to, immediately following, and 5, 10, and
15 min following the exercise bout. This scale is contained in Appendix H.

Procedure

All participants completed the demographic questionnaire, BDI-II, DCSES, and

RSQ at study entry, prior to the beginning of the exercise intervention. A 9-week

intervention was planned based upon the results of the Craft and Landers’ (1998) meta-

38

analysis which indicated that exercise interventions of 9-weeks or longer were most
effective in alleviating symptoms of depression. Therefore, participants in the control
group were followed for 9 weeks. Members of this group completed the BDI-II, the
DCSES, and the RSQ again after 3, 6, and 9 weeks. These three questionnaires were
counterbalanced in terms of order of administration over the three time periods.
Questionnaires were mailed to participants, which allowed them to complete the
inventories privately and conveniently. Individuals in this group were instructed not to
begin an exercise program during the 9 weeks of the study.

Those in the exercise group began an exercise intervention consisting of 3 days
per week of moderate intensity physical activity. Participants exercised, in groups of 2-4,
twice per week and also completed one exercise session per week at home on their own.
Each exercise session consisted of a brief (5 min) session of stretching followed by
exercise on stationary cycle ergometers and treadmills. The ﬁrst week of the study
consisted of familiarizing participants with stretching techniques, monitoring heart rate
via radial or carotid pulse, and how to properly use the exercise equipment. The
participants in this study were very sedentary and, as such, Weeks 2-3 of the study were
conducted at a “comfortable” pace for a total of 20 min. For the remaining 6 weeks of
the study, participants were asked to ride or walk at 50-75% of HRR for the 30-min bout
with heart rate monitored throughout to ensure the appropriate exercise intensity was
maintained for the entire bout. The exercise bout was followed by a brief (5 min) cool
down period and 5 min of stretching. For the home based exercise sessions, participants
were free to engage in whatever type of exercise activity they chose. Aerobics video-

tapes were provided to participants to assist them in their home based session. For the

39

home based activity, participants were instructed to follow the general exercise protocol
of stretching, monitoring heart rate throughout exercise, cool-down, post-exercise stretch,
etc. During each exercise session, participants reported their current mood immediately
prior to and following the exercise bout. They then continued to rate their mood every 5
min for the 15 min immediately following the exercise session. Participants also rated
their level of enjoyment for the exercise bout as well as their perceived exertion for the
exercise session. This intervention lasted 9 weeks with the participants completing the
previously described questionnaire battery (BDI-II, DCSES, RSQ) at study entry, 3, 6,
and 9 weeks. These questionnaires were counterbalanced in terms of order of
administration across the three time periods. The participants in the exercise group also
completed the questionnaires at home and then returned them to the study investigator.
The researcher attempted to facilitate a mastery experience during this 9-week
exercise intervention. During Weeks 1-3, the researcher guided the participants through
their stretching, assisted them in monitoring their heart rates, provided them with a target
heart rate range based on HRR, helped them regulate the intensity of their exercise
session, etc. During Weeks 4-6, the participants took a more active role in the process.
They stretched on their own, monitored their own heart rate, and attempted to adjust their
exercise intensity to remain within their target heart rate range. They were also given
information on how to calculate their target heart rate range. During the ﬁnal 3 weeks of
the intervention, the participants were responsible for the entire exercise session. They
stretched on their own, computed their target heart rate range, monitored their heart rates
and exercise intensity, completed the 30-min exercise bout, and cool down period without

assistance from the researcher. The researcher was present to answer questions but

40

encouraged the participants to complete the workout session on their own. Furthermore,
having the participants exercise one day per week on their own should have assisted in
the development of a mastery experience.

Analyses

Descriptive statistics were computed for subject characteristics and study
variables. To check for potential group (i.e. control, exercise) differences at study entry,
subject characteristics were examined using student’s t tests for continuous variables and
Chi square analyses for categorical variables. A one-way analysis of variance (ANOVA)
was conducted to check for pre-existing group differences on study dependent variables
(depression score, coping self-efficacy, and response style).

To test the ﬁrst three study hypotheses, four separate repeated measures
multivariate analysis of variance (MANOVAs) were utilized to examine group (control,
exercise) differences across time on BDI-II (depression), DCSES (coping self-efﬁcacy),
and RSQ (rumination and distraction). In an attempt to increase statistical power for
these multivariate tests, data obtained at 6 weeks was not utilized. Therefore, time points
used for the repeated measures MAN OVAs were study entry, 3 weeks, and 9 weeks.
Follow-up univariate analysis of variance (ANOVA) was utilized to determine group
differences at each time point (i.e., whether the exercise or control group had higher
mean scores). Within subjects repeated measures MANOVA was then conducted to
determine at what time points these group differences occurred (i.e. if change occurred
from study entry to Week 3 or from Week 3 to Week 9). Effect sizes (Cohen’s d) were
also calculated for dependent variables at Week 3 and Week 9 using a pooled standard

deviation as described by Hedges & Olkin (1985).

41

To test the fourth hypothesis that coping self-efﬁcacy, rumination, and distraction
would be related to depression score, standard multiple regression analyses were
conducted. Regression analyses were conducted at Week 3 and Week 9. The best
predictors of depression score at those two time points were examined.

Finally, exploratory analyses were conducted to determine potential relationships
between acute mood and symptoms of depression. Data related to the participants’ rating
of pro-exercise mood, post-exercise mood, length of the mood elevation, enjoyment of
the exercise session, and RPE were ﬁrst collapsed. Beginning with Week 2 of the study
(Week 1 was primarily informational and mood data was not collected), averages for pre-
exercise mood, mood immediately post-exercise, length of mood elevation, enjoyment,
and RPE were calculated for 3 time periods: Time 1 (Weeks 2-3), Time 2 (Weeks 4-6)
and Time 3 (Weeks 7-9). Within-subjects (time) repeated measures MANOVAs were
conducted to determine if these average ratings changed across the course of the study.
Pearson’s correlations were also conducted to examine relationships between BDI-II,
DCSES, RSQ, pre-exercise mood, post-exercise mood, enjoyment, and RPE for each of

the three time periods.

42

CHAPTER FOUR
Results

At study entry, the two groups did not differ signiﬁcantly (p > .05) on age, marital
status, level of education, age that depression was ﬁrst diagnosed, number of prior
hospitalizations for depression, severity of depression, or type of antidepressant
medication. Subject characteristics are presented in Table 1. Overall, adherence to the
exercise program was good among the members of the exercise group. Most participants
who missed sessions scheduled make-up sessions in order to complete the study protocol
of 3 sessions total per week. Participants in the exercise group completed a mean of 23.3
sessions. This was 86.4 % of the scheduled sessions.

Scores for dependent variables (severity of depression, coping self-efﬁcacy, and
use of rumination and distraction) at study entry were examined using ANOVA and
results showed that the two groups did not differ signiﬁcantly [BDI-II: F (1, 18) = .55, p
= .47; DCSES: F(1, 18) = 2.28,p = .15; Rumination: F(1, 18)=1.03,p = .33;
Distraction: F (l, 18) = 3.45, p = .08]. Means and standard deviations for these study
variables for all time points are presented in Table 2.

To test the ﬁrst hypothesis that a chronic exercise intervention would be
associated with a reduction in depression, a Group (control, exercise) X Time (study
entry, 3 weeks, 9 weeks) repeated measures MANOVA was conducted. The Group X
Time interaction was signiﬁcant (Wilks’ A = .66, F (2,16) = 4.2, p < .05) as was the
within subjects main effect for Time (Wilks’ A = .56, F (2,16) = 5.5, p < .05). The
between subjects main effect for Time was also signiﬁcant, F (1,17) = 7.0, p < .05.

Follow-up tests for the interaction using univariate ANOVA indicated that the exercise

43

Table 1

Subject Characteristics.

Control (N = 10)

Exercise (N = 9)

 

Mean (S.D.) Mean (S.D.) tor X2 p
Age (years) 42.9 (13.3) 43.6 (13.9) = - .11 0.92
Age ﬁrst 28.8 (12.5) 31.1 (13.3) t= - .39 0.70
diagnosed (years)
Number ofprior 0.1 (0.3) 0.6 ( 1.1) = - 1.17 0.24
hospitalizations for depression
BDI-II score 24.9 (12.6) 21.2 ( 8.4) t = .74 0.47
(Severity of depression)
Marital status X2= 2.04 0.57
Single 3.0 3.0
Married 5.0 6.0
Widowed 1.0 0.0
Separated 1 .0 0.0
Highest level of education achieved X2 = 2.25 0.32
High School 4.0 1.0
College 3.0 5.0
Graduate School 3.0 3.0
Type of antidepressant medication X2 = 0.57 0.75
SSRI 6.0 5.0
Pre/Post Seratonin 3.0 3.0
Norepi/Dopamine 2.0 2.0

44

 

3 "mm
2.2.: A? :2

me-nmm
3.39.2 8.25.3
2 "mm
8.8: a: v2
Nz-umm
25$ 9.2;:
omonm 75:00
$3

2 "mm

an 3.2 can KAN
N;-umm

8m :2 3.55.8
2 "mm

5 V: A2 Xx
Ne-umm

an :2: A2398

86be 6.5.80

3%

3 "mm
3:93 8.30.8

mz-umm
3.: 3: AS :9.

3 "mm

8.82 A2 CS
2.1%.

3&3 32:3

aﬂodoxm 35:00

843

5; 98 c .c 4.8
86 a?

8.: we a: 3
9.3 N: Ga: 3.0.
ommodoxm .8250
ﬁg

5:855

: .3 3e ceaseé

mmmUQ

=-~Qm

 

.mmx nae ”~wa SAQQ to 2E5 896‘ mzeceSeQ 3.538% 35» .26»:

N 23

45

group was less depressed than the control group at 3 weeks, F (1,18) = 12.8, p < .01, and
at 9 weeks, F (1,18) = 7.1,p < .05. Within subjects repeated measures MANOVA
indicated that the control group did not signiﬁcantly reduce their depression scores from
study entry to 3 weeks, Wilks’ A = .10, F (1,9) = .01, p > .05, or from 3 weeks to 9
weeks, Wilks’ A = .92, F (1,9) = .80, p > .05. Further, the exercise group had a
signiﬁcant reduction in depression from study entry to 3 weeks, Wilks’ A = .41, F (1,8) =
11.4, p < .01, but no ﬁrrther reduction from 3 weeks to 9 weeks, Wilks’ A = .72, F ( 1,8) =
3.1, p > .05. This indicates that exercise was associated with a reduction in depression by
3 weeks time and this reduction in depression in the exercise group was maintained to the
end of the 9-week study. Means, standard deviations, and effect sizes for depression
scores across time are presented in Table 2. Figure 1 represents the signiﬁcant Group X
Time interaction.

The second hypothesis predicted that c0ping self-efﬁcacy would increase across
time in members of the exercise intervention. Repeated measures MANOVA, using
coping self-efficacy as the dependent variable, showed that there was a signiﬁcant Group
X Time interaction [Wilks’ A = .50, F (2,16) = 8.2, p < .01]. The within subjects main
effect for Time was not signiﬁcant, Wilks’ A = .90, F (2,16) = .93, p > .05. The between
subjects main effect for Group was also signiﬁcant, F (1,17) = 17.2, p < .01. Results of
follow-up univariate ANOVA for the interaction indicated that the exercise group had
higher coping efficacy at 3 weeks [F (1,18) = 16.6, p < .01] as well as at 9 weeks [F
(1,18) = 10.1, p < .01]. Within subjects repeated measures MANOVA indicated that both
the control group and the exercise group had a signiﬁcant change in efﬁcacy score from

study entry to 3 weeks [Control group: Wilks’ A = .52, F ( 1,9) = 8.5, p < .05; Exercise

46

 

 

 

 

95...
9.82, m mxooz, m Eco 33m
0

i m 8
- 2 m
1 mr my
01. f l i ON 0
i i t iiiii I . mm m

- om

:oﬁmoEoD .

 

 

 

$8.6m. NWNQQ ae\=e.:oe§~=~ 2kg k. @399

_ 2am:

47

group: Wilks’ A = .60, F (1,8) = 5.3, p < .05] but neither group showed further
improvement from 3 weeks to 9 weeks [Control group: Wilks’ A = .10, F (1,9) = .02, p >
.05; Exercise group: Wilks’ A = .96, F (1,8) = .33, p > .05]. The two groups both
demonstrated changes in efﬁcacy score across the 9-week study. The exercise group
increased their self-efficacy score, while efﬁcacy decreased in the control group. This
may have contributed to the signiﬁcant Group X Time interaction. However, those in the
exercise intervention showed signiﬁcantly greater increases in coping self-efﬁcacy than
those in the control group. This increased efﬁcacy emerged by 3 weeks time and was
maintained throughout the remainder of the study. Means, standard deviations, and effect
sizes across time for coping self-efﬁcacy are presented in Table 2. Figure 2 represents
the signiﬁcant Group X Time interaction.

The third hypothesis predicted that those in the exercise intervention would report
a decreased tendency to use ruminative strategies and an increased use of distraction
techniques across time. Repeated measures MANOVA was first conducted with
rumination as the dependent variable. The Group X Time interaction was not signiﬁcant
[Wilks’ A = .89, F (2,16) = 1.0, p > .05], but the main effect for time was signiﬁcant
[Wilks’ A = .56, F (2,16) = 6.3, p < .01]. The test of between subjects main effect for
Group was also significant [F (1,17) = 4.9, p < .05]. These ﬁndings suggest that,
regardless of group (control, exercise), all participants decreased their use of ruminative
strategies across time. Because group means appeared different and low statistical power
was suspected for the non-signiﬁcant Group X Time interaction, a follow-up univariate
ANOVA was conducted. Results showed that the exercise group had signiﬁcantly lower

scores for use of rumination than the control group at 3 weeks [F (1,18) = 5.5, p < .05]

48

 

wet

 

 

 

 

 

 

 

>55

3me m mxomz, m >25
«I! ........ I... i... at... I... It. i
.1... Id T

.1 ll\I

l

 

 

 

>omoEou=om mcaoo

(DNLOLDV

91033 $3300

 

 

.88m mmmoa 5.. 5:688:— 25... x 9.80

N 2am:

49

and at 9 weeks [F (1,18) = 7.0, p < .001]. Means, standard deviations, and effect sizes
across time are presented in Table 2. Figure 3 represents the signiﬁcant main effect for
Time.

To determine whether the use of distraction increased across time more in the
exercise group than in the control group, a repeated measures MANOVA using
distraction as the dependent variable was conducted. The Group X Time interaction was
not signiﬁcant [Wilks’ A = .93, F (2,18) = .61, p > .05] and neither was the main effect
for Time [Wilks’ A = .90, F (2,18) = .88, p > .05]. The between subjects main effect for
Goup was signiﬁcant [F (1,17) = 7.8, p < .05]. These ﬁndings suggest that there was not
an increase in use of distraction across the 9 weeks of the study for either the control
group or the exercise group. Again, because the group means appeared different and low
power was suspected for the non-signiﬁcant Group X Time interaction, univariate
ANOVA was conducted for each time point to determine if the groups were different.
Results indicated that exercise group members had a higher use of distraction techniques
at 3 weeks [F(1,18) = 10.6,p < .01] but not at 9 weeks [F(1,18) = 2.2,p > .05]. Means,
standard deviations, and effect sizes for distraction scores across time are presented in
Table 2. Figure 4 represents the data for distraction scores across time.

Next, to test the hypothesis predicting that obtained levels of coping self-efﬁcacy,
rumination, and distraction would be related to current levels of depression, standard
multiple regression analyses were conducted. The best predictors of depression score at
study Week 3 and Week 9 were examined. At Week 3, depression score at Week 3 was
entered as the dependent variable, with depression score at study entry (included as a

covariate), self-efficacy, rumination, and distraction scores at Week 3 entered as

50

 

SE...

9.83 m 9.695 m Eco >335

 

 

 

 

 

 

 

 

 

on

1 mm

1 ov

.! I
iiitiiii. -mv
.rl IO
om
cosmEEsm

61033 $33

 

 

98% g gages ae§ue§m Se:

m 2a;

51

 

 

 

 

 

 

 

 

 

6E2. Eco
ﬂow? a. 9.33 m 22.3
om
t .. .... .... .«i .. .. .. 4 mm “on
- S
- om m
m
mm

 

 

 

com—3.35

 

 

.aq =0 «SKOUW

v 2&5

52

predictors. Among exercisers, self-efﬁcacy ()8 = -.74, p > .05) and study entry depression
score (1? = -.59, p > .05) were the best predictors of depression at Week 3. Although both
predictors were non-signiﬁcant, self-efﬁcacy approached signiﬁcance at p = .07. Each
predictor had a negative relationship with the outcome, indicating that increased self-
efﬁcacy was related to a reduction in depression and that those with higher depression
scores at study entry had the greatest improvement in depression by Week 3. These two
variables accounted for 30.2% of the variance.

For the Week 9 time point, depression score at Week 9 was entered as the
dependent variable and depression score at Week 3 (included as a covariate), self-
efﬁcacy, rumination, and distraction at Week 9 were entered as predictors. Self-efﬁcacy
(,6 = -.65, p < .05) was the best predictor of depression after controlling for depression at
Week 3 (ﬂ = .29, p > 05). Self-efficacy had a signiﬁcant negative relationship with
depression score. Therefore, the higher one’s self-efﬁcacy, the lower one’s depression
score. These two variables accounted for 54.0% of the variance.

Finally, exploratory analyses were conducted to investigate the relationship
between mood and depression. Pre—exercise mood, mood immediately post-exercise,
length of mood enhancement, enjoyment, and RPE were examined. Length of mood
enhancement for all participants for all exercise sessions was the full 15 minutes for
which mood was assessed. In other words, post-exercise mood never returned to baseline
(pre-exercise) values during any of the time points monitored during this study.
Therefore, this variable was dropped from further analyses. Means and standard
deviations for each of the other exercise mood variables at each time point are presented

in Table 3. Within subjects repeated measures MANOVA indicated that there were no

53

 

54

8.: a: 8.: n: 8.8 n: 8838 838.8% mean

8.8 3 8.8 3 2 .8 E 58 cease co 858.5

G8 a; 3.8 od 88 E 86.88 88 30360688 coo—2

8.8 3 8.8 no 88 9o geese 8 BE .82
8.» 9.83 3. £83 2 e83

 

.3335; Eco: 88.23% ae\n=e.=e.§ oQ haehzear ~28 26»:

m 033.

signiﬁcant changes across time for any of the variables examined [Pre-exercise mood:
Wilk’s A = .70, F (2, 7) = 1.52, p = .28; Mood immediately post-exercise: Wilk’s A = .86,
F (2, 7) = .60, p = .58; Enjoyment of the exercise bout: Wilk’s A = .56, F (2, 7) = 2.79, p
= .13; RPE: Wilk’s A = .51, F(2, 7) = 3.32,p = .10].

Pearson’s correlations among mood variables and dependent variables for each
time point resulted in several signiﬁcant (p < .05) relationships. Correlations are
presented in Tables 4-6. The changes across time among the relationships between RPE,
post-exercise mood, enjoyment, and BDI-II score were the most interesting. The
correlation between RPE and post-exercise mood shifted from a negative relationship (r =
-.31) to a signiﬁcant positive relationship (r = .73). Further, the relationship between
RPE and enjoyment was small and non-signiﬁcant (r = .01) early in the intervention but
became stronger and signiﬁcant (r = .74). Finally, the relationship between RPE and

BDI-II score was initially strong and positive (r = .75) but became negative (r = -.39).

55

.8. v m a 88888 832.8 .

 

2.

805.

2.-

oer

E.

.3.

mm.

Sr

No...

2.-

3.

A: ..

oer

M2...

on .-

.m.

S.

3.

£83 m a 28m egos—ED .w
9.83 m a 28m cosmic—am s
8.83 n a 0:08 mmmUQ .c

- 9.003 m 3 28m =-_Dm .n

«2.. - 5on0 338.2. .8 95.3 .v
mm. 8. - 53 8.828 2: .8 80:38.5 .m
2.- 2.- .E. - 9.6.23 :8 522858 882 .N
a..- 8.- NM. .8. - 8.228 2 8.8 8oz ._

m e m N _

 

.~ EEK B 833.26; 3838me BS» .8353; hoe: MzoEV 28:32.39

8 23

56

2 .-

NNr

m5.

NN.

a.

_m.

I...

2..

mm.

an.

em.

2.

5.-

83...

em...

3..

hm...

3.

mm.

3“.

em.

3.

83.. -

.mn. :3. u

no. 83.. 1b. -
v m N _

._ o. v a 8 ~=8E=3m 8:39:00 .3
.3. v a a 285.88 525280 .

3.83 o 8 089. 889.85 .m
8.83 o 8 088 88553— H
383 e a 28m mmmoa 8

8.83 o 8 28m =-Em .n

.8888 3:88.. .8 95.3 .v
88 88.5.8 2: .8 82525 .m
8888 so; 5088088 882 .N

3.88% o. 88 322 4

 

N as: 8

«$8.53 .585me 38 832.6; woo: wcoﬁv‘uzoaSwhoU

n 055,—.

57

.8. v a a 585:»; 832.8 -

 

NN.

cm.

mm .-

2.

we.

mm.-

mm.-

3V.-

2.-

3.-

cm.-

8.

2.-

.55.-

mm.

2.

we.

hm.

am.-

2...-

2.-

we.-

on.

2.

ca.-

.3.

Q.-

mm.

9.83 a E 28m :28ng .w
8.8.: a 3 28m cocmﬁﬁam .5
8.83 a a 28m $89 .o

3.83 a a 28m =-_Om .n
:oono 328qu go wig»— .v
Eon SESB on. .«o EoEzOEM .m
9:298 .8; boaﬁoeg “.82 .m

- 86.85 9 8.5. 302 ._

 

.m ~25 B 333.53 283$me VS» 3336\— V8: MacEVntozuEto-u

e 038.

58

CHAPTER FIVE
Discussion
Overall Effect of Exercise on Depression

The ﬁrst hypothesis predicted that an exercise intervention would be associated
with a reduction in depression among clinically depressed women. This hypothesis was
supported by the data. All women began the study with “moderate” levels of depression
based on their scores on the BDI-II. At the conclusion of the study, the women in the
control group were still moderately depressed whereas the women in the exercise
intervention group were only minimally depressed. Therefore, a moderate intensity (50-
75% HRR) exercise program consisting of 3 exercise sessions per week was associated
with a reduction in the symptoms of clinical depression. This ﬁnding mirrors the results
of numerous previous studies demonstrating a reduction in depression following
involvement in an exercise program (Blumenthal et al., 1999; Brown et al., 1992; Dimeo,
hBaurer, Varahm, Proest, & Halter, 2001; Doyne, Chambless, & Beutler, 1983; Martinsen,
Hoffart, & Solberg, 1989; Martinsen, Medhus, & Sandvik, 1985).

The women in the exercise group experienced a signiﬁcant reduction in their
depression by the third week of the study. Ewart (1995) contends that one obstacle to
understanding the mechanisms mediating the relationship between exercise and
depression is the insistence that mood changes following exercise must be driven by
physiological changes such as maximal aerobic capacity, muscular strength, or heart rate.
Several studies, such as this one, have found psychological beneﬁts of exercise in short
time periods (e. g., Brown et al., 1992; Doyne et al., 1987). Others have also shown small

relationships between psychological beneﬁts and physiological changes (Blumenthal et

59

al., 1999; Doyne et al., 1987; Martinsen, Hoffart, & Solberg, 1989; Veale et al., 1992).
However, physiological parameters were not assessed in this study and therefore cannot
be ruled out as potential mediators of this relationship. Research indicates that
physiological adaptations to training, such as decreased heart rate, reductions in
catecholamine response, and attenuation of the slow component of peak 02 uptake, can
occur within the ﬁrst 2-3 weeks of exercise training (Winder, Hagberg, Hickson, Ehsani,
& McLane, 1978; Womack, Davis, Blumer, Barrett, Weltman, & Gaesser, 1995).
Therefore, while the reduction in symptoms of depression occurred very rapidly and the
focus of this study is on psychological mechanisms, physiological mechanisms remain
plausible and should not be discredited.

Women in this study chose the group in which they would participate. As such, it
is possible that the women in the two groups differed at study entry on some unmeasured
subject characteristic that had an inﬂuence on this study outcome. For example, perhaps
the women who chose the exercise intervention group had already decided to make a
commitment to an exercise program. The Transtheoretical Model of behavior change
(Prochaska & DiClemente, 1983) suggests that there are several stages of change that
range from “precontemplation” (no intention to start exercising regularly) to
“maintenance” (engaging in regular exercise for more than 6 months). This theory
predicts that until an individual reaches the “action” stage (immediate intention and
commitment to change), she is unlikely to successfully start and maintain an exercise
program. Future research should screen study participants to assess their current stage of
change. It is possible that an exercise intervention may be most effective for those who

have committed to incorporating exercise into their lifestyle. This may also aid

60

researchers in equalizing groups at study onset and increase the likelihood that
participants will adhere to the exercise intervention.
Exergise, Qgping Self-Efﬁcacy, and Depression

The second hypothesis examined one of the previously proposed psychological
mechanisms, coping self-efﬁcacy. It was predicted that the women in the exercise
intervention group would report increased levels of coping self-efﬁcacy. It was also
hypothesized that obtained levels of c0ping self-efﬁcacy would be related to current
levels of depression. Both hypotheses were supported by the data. Women in the
exercise group had signiﬁcantly higher coping self-efﬁcacy by the third week of the
study and this heightened level of efﬁcacy was maintained throughout the remainder of
the study.

The relationship between exercise and coping self-efﬁcacy (rather than
generalized feelings of efﬁcacy or efﬁcacy to engage in exercise) has not been previously
tested in women suffering from clinical depression. However, research conducted on
adults with anxiety disorders supports this ﬁnding. Steptoe and colleagues (1989)
compared the perceived coping ability of anxious adults following involvement in either
an aerobic exercise program or a placebo-control strength and ﬂexibility program. The
authors reported that their moderate intensity aerobic exercise program was associated
with reductions in anxiety and increases in coping self-efﬁcacy. These psychological
beneﬁts were not signiﬁcantly related to initial ﬁtness level, changes in ﬁtness, or age.

There are several ways in which mastering an important health behavior such as
exercise could lead to enhanced feelings to cope with one’s depression. First, all the

participants were physically sedentary prior to the study. Therefore, making the

61

commitment to engage in exercise three times per week was a very proactive step in the
maintenance of their physical health. Adherence to this program may have increased the
womens’ awareness that committing themselves to the management of other health
behaviors (e.g., proper nutrition, appropriate sleep schedules) could help control the
symptoms of their depression. Second, the women were very unfamiliar with the
“process” of engaging in an exercise session. During the study, they learned to stretch,
monitor heart rate, use exercise equipment, etc. Again, learning and mastering new
health-related skills may have given them the conﬁdence necessary to learn to master
new techniques to deal with their symptoms. Third, goal setting was promoted
throughout the exercise program. As goals were achieved and new goals set, conﬁdence
to achieve desired outcomes likely increased. Goal setting may have become viewed as a
beneﬁcial self-regulatory strategy to manage depressive symptoms. Fourth, the exercise
participants were required to complete one exercise session per week on their own at
home. The ability to engage in exercise independent of the group and exercise instructor
could have transferred to feelings of conﬁdence to take a more self-managed approach to
the control of depressive symptoms. Finally, as the participants began to notice their
depression subsiding, they verbalized that their improved affect was due to their
involvement in the exercise program. Again, this may have led to the belief that they
could, in fact, do something behaviorally that would impact their symptoms and that they
weren’t simply “victims” of depression.

In this study, coping self-efficacy was the best predictor of depression scores
(after controlling for previous levels of depression) among exercise group members at

Week 3 and Week 9. Coping self-efﬁcacy demonstrated a negative relationship with

62

depression indicating that higher levels of efﬁcacy were associated with lower levels of
depression. While this does not provide deﬁnitive evidence that c0ping self-efﬁcacy is
the psychological mechanism by which exercise exerts a positive inﬂuence on
depression, it does allude to that possibility and indicates that researchers should continue
to study self-efﬁcacy theory in relation to exercise and depression. This ﬁnding is in
accordance with Bandura’s (1997) contention that individuals who feel inefﬁcacious to
control their thoughts, feelings, emotions, and reactions are generally more depressed
than those with high efficacy.

Therefore, the ﬁndings from this study suggest that the enhancement of coping
self-efﬁcacy should be an important component in the treatment of depression.
Involvement in an exercise program can provided a meaningful mastery experience
through which c0ping self-efﬁcacy can be augmented. If exercise is used as an adjunct
therapy in the treatment of this disorder, opportunities for mastery should be emphasized

and positive feedback provided.

Exercise, Response Style, and Depression

 

The third study hypothesis predicted that involvement in an exercise program
would be associated with a decreased tendency to use rumination as a response style and
an increased use of distraction techniques. Further, it was hypothesized that response
style would be associated with symptoms of depression. These hypotheses were partially
supported by the data. All women reported a reduced use of ruminative strategies across
time, with the exercisers having signiﬁcantly lower mean scores at Week 3 and at Week
9. Results also indicated that the exercise group members had a higher use of distraction

techniques at Week 3 but not at Week 9. Therefore, exercise was associated with a

63

reduction in the use of rumination across the 9-week study and an increase in the use of a
distraction response style at Week 3. However, data did not support the prediction that a
response style would be associated with depression among exercise group participants.
No previous studies have examined whether an exercise intervention is associated
with a change in response style. Prior research has consistently found that rumination
predicts the duration and severity of depressed mood, however, the ﬁndings for
distraction have been mixed with distraction predicting severity of depression in some
studies but not others (Nolen-Hoeksema, 1991). While a positive side effect of exercise
may be a more beneﬁcial response style, it does not appear that either rumination or
distraction is the psychological mechanism explaining the antidepressant effects of
exercise. There are several potential explanations for why response style did not predict
depression in the exercise group. With respect to rumination, it is possible that other
psychological constructs, such as coping-self-efﬁcacy or social support, may buffer the
effects of a ruminative response style in individuals who exercise. Thus, while the person
may still have a tendency to use ruminative strategies, if exercise results in increased
conﬁdence and a supportive social network, the use of rumination may not have such a
negative impact on his/her depression. Nolen-Hoeksema (1991) argues that social
support may mediate the relationship between rumination and depression if the social
support encourages the depressed individual to stop ruminating and start engaging in
distracting activities. Therefore, it is conceivable that exercise group participants may
provide this type of social support to each other and help attenuate the effects of
rumination on depression. Future research should assess the perceptions of social support

among participants.

64

As for distraction, it remains highly possible that distraction is occurring during
exercise activities. Participants may have been temporarily distracted from their
depression during each acute exercise bout. If so, that temporary distraction might be
responsible for the transient mood elevation that occurred following exercise. Response
styles theory predicts that exercise, if an effective distractor, would lead to a temporary
elevation in mood which could provide time for more effective problem-solving (Nolen-
Hoeksema, Morrow, & Fredrickson, 1993). Therefore, while there was not strong
evidence to support a change in response style as the mechanism for reductions in
depression, distraction during each exercise bout cannot be ruled out.

It is also possible that an increased use of distracting activities is an important
predictor of depression but that such changes were not measured adequately in this study.
For example, perhaps exercise leads to an increased use of a variety of distracting
activities such as hobbies or various physical activities that were not assessed by the
inventory. Or, possibly, a person chooses to use one type of activity that she enjoys as
her primary distracting activity. These types of changes would not necessarily be
reﬂected in her distraction score. As Nolen-Hoeksema (1991) discusses, research related
to a distractive response style must next ﬁnd a way to measure the variety of tasks an
individual uses to distract him/herself and the degree to which the task demands cognitive
involvement. A depressed person may utilize one or two tasks that require much
concentration and attention. These would be effective distractors that lead to mood
elevation but would not necessarily result in a noticeable change in score on the
Distractive Response Style (DRS) subscale. Therefore, an alteration in the use of a

distractive response style also remains a possible explanation for the antidepressant

65

effects of exercise. Future researchers should examine whether participants experience
distraction from their thoughts and worries during the exercise bout and whether exercise
leads to a change in the type of distracting activities used or the amount of involvement
invested in distracting activities. Previous research has only compared the effect of
exercise to other distracting activities (Doyne et al., 1983; Klein et al., 1985; McNeil,
LeBlanc, & Joyner, 1991), and, as such, ﬁndings do not answer those types of questions.
Therefore, an exercise intervention program appears associated with a positive
change in response style. If exercise is utilized as an adjunct therapy, participants should
be discouraged from discussing their depression during an exercise bout and encouraged
to focus on aspects of the program that might provide distraction. Activities such as
monitoring heart rate and exercise intensity and engaging in social interaction with other
participants should provide distraction from worrisome thoughts and feelings.

Exercise Mood Elevation. end Depression

 

As no previous studies were located that had examined acute exercise and mood
in the clinically depressed, the examination of the relationships between exercise, mood
elevation, and depression was exploratory in nature. Potential mood elevation post-
exercise, the length of that mood elevation, and the relationship between transient mood
elevation and depression was of interest. There were no formal a priori hypotheses
related to this area of investigation. Data for exercise group participants indicated that all
participants, during all exercise sessions, experienced an elevation in mood following
each acute bout of exercise within the 9-week intervention. Further, this mood elevation

lasted for the 15 min following each exercise session. Analyses examining changes

66

across time, while non-signiﬁcant, showed a trend for increases in pre-exercise mood,
post-exercise mood, enjoyment of the exercise bout, and RPE for the exercise bout.

Mood elevation as a result of acute exercise has not been previously studied in
clinically depressed participants. Results of this study indicate that depressed individuals
engaging in 30 min of moderate intensity exercise experienced mood enhancement
following each acute bout similar to those in the general population. Participants rated
their mood on a general scale that ranged from “negative, sad, down” to “positive, happy,
upbeat”. Researchers should next determine if acute exercise has an inﬂuence on both
the negative and positive dimensions of mood as demonstrated by previous researchers
using non-depressed participants (Arent, Landers, & Etnier, 2001; Berger & Owen, 1988;
McGowan, Talton, & Thompson, 1996; Petruzzello, Jones, & Tate, 1997; Yeung, 1996).
Further, the mechanisms for this mood enhancement remain unknown. As discussed
previously, perhaps participants were temporarily distracted from their depression and
this led to an improved mood following exercise.

The mood elevation experienced by exercise participants in this study lasted for at
least the 15 min following exercise. Mood was only recorded for the 15 min immediately
post-exercise and therefore it remains unclear whether this transient elevation in mood
actually persisted longer. Solomon’s (1980) opponent process theory predicts that the
negative feelings associated with exercise should decrease over time and that the length
of transient mood elevation should increase across time. The correlational data from this
study may provide indirect evidence to support this theory. Across the 9-week
intervention, the relationship between RPE and mood shiﬁed from a negative relationship

to a positive relationship. Further, early in the intervention, the relationship between RPE

67

and enjoyment was very small and non-signiﬁcant. As time progressed, this relationship
became much stronger and positive. Therefore, it appears that participants were enjoying
the exercise more across time, their mood was enhanced, and, in general, they felt more
positive about the exercise bout the harder they perceived themselves to be working.

Petruzzello et al (1991) found partial support for this theory using non-depressed
participants. However, it remains uncertain whether pre-exercise affect (which can be
quite negative in depressed participants) would alter the expected outcomes as predicted
by the theory. Future researchers should examine not only pre and post-exercise mood,
but should also try to ascertain what types of feelings the participant is experiencing
during the exercise bout. Further, it appears that 15 min is not long enough to adequately
assess the length of post-exercise mood. It is possible that mood elevation lasts much
longer, as has been demonstrated with the non-depressed (Berger & Owen, 1983;
Hanson, Stevens, & Coast, 2001; Maroulakis & Zervas, 1993). Therefore, mood changes
in depressed participants should be tracked for several hours post-exercise.

Across time, during the 9-week exercise program, it was anticipated that
participants would experience changes in pre-exercise mood, mood immediately post-
exercise, enjoyment, and RPE. These ﬁndings were non-signiﬁcant. Although the trends
were in the anticipated direction, the effects were small. The participants' mood prior to
exercise gradually increased across the three time points analyzed. This may be related
to the concurrent reduction in depression that these women were experiencing. The
increase in pre-exercise mood however was quite gradual and may also simply reﬂect the

day to day variation in mood that we all experience.

68

All participants rated mood immediately post-exercise on the positive end of the
scale (i.e. from 0 “neutral” to 3 “happy, positive, upbeat”) for all exercise sessions. This
gradual increase in mood immediately post-exercise may represent greater mood
enhancement across time (as predicted by the opponent process theory) or may actually
mirror the ﬁnding that pre-exercise affect was better across time. Again, more research is
needed to examine how mood enhancement changes across time and how long such
mood enhancement is expected to last.

Participants’ enjoyment of the exercise sessions gradually increased over time as
well. Perhaps the exercise became easier which resulted in more enjoyment. Their
increased enjoyment of the exercise session could have also resulted from enhanced
feelings of mastery. Maybe, as participants became more familiar with the protocol, how
to use the exercise equipment, and more conﬁdent to complete the exercise session on
their own, they enjoyed the exercise more. It is also likely that their enjoyment of the
exercise was related to the social nature of the program. As social support was developed
and friendships emerged, the participants may have enjoyed the endeavor more.

Rating of perceived exertion also changed minimally across time. Participants
reported exercising in the “somewhat hard” to “hard” range and this was expected for a
moderate intensity program. Moderate intensity exercise was the target intensity for the
9-week program. Therefore, because exercise intensity did not change across time, large
changes in RPE would be unexpected. As participants became more accustomed to
exercise and as their depression subsided, they may have felt capable of working more
intensely during exercise bouts. Overall, these ﬁndings are in accordance with what

would be anticipated.

69

Exploring the relationships among the mood variables and dependent variables
resulted in another interesting ﬁnding. In the ﬁrst few weeks of the exercise intervention,
there was a strong positive relationship between RPE and depression score. This
indicates that the more severe one’s depression the higher the rating of effort. Across
time, however, this relationship became negative. Therefore, the lower one’s depression
the higher the effort exerted. This ﬁnding could be anticipated considering many
individuals with clinical depression experience psychomotor retardation (American
Psychiatric Association, 1994). As depression began to subside among exercise group
members, symptoms such as psychomotor retardation should have been less severe.
Therefore, in the later weeks of the study, the participants probably felt more physically
capable of exercise. Dunn et al (2001) called for studies examining effort sense in those
suffering from anxiety and depressive disorders. The ﬁndings of this study indicate that
depressed individuals may initially rate their exertion in relation to their depressive
symptoms. However, once their depression begins to subside, it appears that they make
exertion judgements independent of the severity of their depression and rate exertion in a
manner appropriate to the prescribed exercise intensity.

In summary, many novel ﬁndings emerged from these exploratory analyses
related to mood. First, depressed individuals do experience mood enhancement
following acute bouts of exercise. This mood enhancement can be expected to last for at
least 15 min following the exercise. Second, while it does seem that depressed people
have realistic perceptions related to effort, ratings of exertion may be inﬂuenced by
severity of depression and other affective cues early in an exercise program. Finally, the

data did not support the idea that these transient changes in mood play a mechanistic role

70

in the relationship between exercise and depression. Neither pre or post-exercise mood
nor enjoyment of the exercise bout were related to depression score at any of the time
points analyzed.
Conclusions

There were many important ﬁndings that resulted from this study. A moderate
intensity exercise program was associated with a reduction in depression among women
who were moderately depressed. Further, data provided support for cOping self-efﬁcacy
as a psychological mechanism for the antidepressant effects of exercise. It also appears
that involvement in an exercise program is associated with positive changes in response
style. That is, a reduced tendency to ruminate and increased use of a distractive response
style. Depressed women experienced transient mood elevation following each acute
exercise bout within the chronic exercise program. Therefore, clinicians should be
encouraged to utilize exercise as an adjunct therapy in the treatment of clinical
depression. Exercise program aspects related to mastery and distraction should be
emphasized. Further, clinicians can educate patients that they will likely experience
mood enhancement quite early in a group aerobic exercise program and that exercise
does not need to be intense for this mood enhancement to occur. Finally, patients should
be informed that perceptions of effort may be related to feelings of depression in the early
phases of an exercise program but that as time progresses they should feel more
physically capable of engaging in exercise and able to put forth increased effort during

the exercise bout.

71

Limitatiens

There are several limitations to the current study that must be addressed. First, a
quasi-experimental design was utilized with participants choosing to be in either the
control or exercise group. Therefore, it is possible that these two groups were not
equivalent at study entry. Analysis of subject characteristics and study dependent
variables indicated that there were no signiﬁcant differences between groups on variables
deemed important. However, there may have been relevant subject characteristics that
differed between the two groups that were not assessed in this study.

Second, reductions in depression among exercise group members may have been
a result of expectancy effects. Perhaps women in that group expected to feel better
because they were engaging in an exercise program. This cannot be excluded as a
potential cause for the reductions in depression. However, it seems unlikely that the
other positive beneﬁts of exercise that emerged (i.e. increases in coping self-efﬁcacy,
reductions in rumination) would have been expected by the participants.

Third, this study did not utilize a placebo-control group. Therefore, the positive
beneﬁts associated with the exercise program may have resulted from a “group” effect or
from interaction with the investigator. Previous studies that have utilized placebo-control
groups have typically found that exercise is still superior in reducing symptoms of
depression and not likely due to group effects (Brown et al., 1992; Doyne, Chambless, &
Beutler, 1982; Doyne et al., 1987; Singh, Clements, & Fiatarone, 1997). However,
results of this study should be interpreted with this limitation in mind. Future research
should compare exercise to other “mastery” oriented activities to help determine whether

group effects inﬂuence the relationship between exercise and depression.

72

Finally, the small sample size of this study resulted in low statistical power. This
could explain several of the non-signiﬁcant ﬁndings. Therefore, before future
researchers disregard the theories explored here, it is important to replicate these ﬁndings
with larger samples. Due to low statistical power, the testing of mediational relationships
via path analysis techniques was not possible. While the data provided mixed support for
the potential mechanisms examined in this study, each of these mechanisms should be
further tested using a larger sample and statistical analyses to address potential mediating

relationships.

73

APPENDIX A

Institutional Review Board Approval and Informed Consent

74

MICHIGAN STATE

U N l V E R SIT Y
April 16, 2002

 

Deborah L. FELTZ
138 IM Sports Circle
Dept. of Kinesiology

TO:

MSU

RE: IRB # 02-077 CATEGORY: FULL REVIEW FULL REVIEW

TITLE: EXERCISE AND CLINICAL DEPRESSION: EXAMINING PSYCHOLOGICAL
MECHANISMS

ANNUAL APPROVAL DATE: March 11- 2002

REVISION REQUESTED: March 27- 2002

REVISION APPROVAL DATE: April 1, 2002

The University Committee on Research Involving Human Subjects' (UCRIHS) review of this project is
complete and I am pleased to advise that the rights and welfare of the human subjects appear to be
adequately protected and methods to obtain informed consent are appropriate. Therefore. the

 

OFFICE OF
RESEARCH
ETHICS AND
STANDARDS

niveretty Committee on
Research Involving
Human Subjects

Michigan State University
202 Girls Hall

East Lansing, MI

48824

51 7/355-2180

FAX: 517/432-4503
www.msuedu/user/ucrihs
E-Mail: ucrihs@msu.edu

"he Midiiaan State University
DEA IS institutional Diversity

Excellence in Action.
MS U is an atﬁmrative—aation,
meta/opportunity institution.

 

UCRIHS APPROVED THIS PROJECT'S REVISION.

Approves the removal of the relaxation group. Consent document revised to reﬂect
this change.

RENEWALS: UCRIHS approval is valid for one calendar year, beginning with the approval date
shown above. Projects continuing beyond one year must be renewed with the green renewal form.
A maximum of four such expedited renewal are possible. Investigators wishing to continue a project
beyond that time need to submit it again for a complete review.

REVISIONS: UCRIHS must review any changes in procedures involving human subjects, prior to
initiation of the change. If this is done at the time of renewal. please use the green renewal form.
To revise an approved protocol at any other time during the year. send your written request to the
UCRIHS Chair, requesting revised approval and referencing the project's IRB# and title. Include in
your request a description of the change and any revised instruments. consent forms or
advertisements that are applicable.

PROBLEMS/CHANGES: Should either of the following arise during the course of the work. notify
UCRIHS promptly: 1) problems (unexpected side effects, complaints. etc.) involving human
subjects or 2) changes in the research environment or new information indicating greater risk to the
human subjects than existed when the protocol was previously reviewed and approved.

If we can be of further assistance, please contact us at (517) 355-2180 or via email:
UCRIHS@msu.edu.

Sincerely,

I’W'

--. ir Kumar. M.D.
Chair, UCRIHS
AK: kj

cc: Lynette Craft

6142 Grossard Avenue
East Lansing. MI 48823

75

Informed Consent

You are invited to participate in a research study examining the relationship between
various types of treatment and clinical depression.

This research is being conducted by Lynette Craft of the Department of Kinesiology at
Michigan State University (432-4219). This research project is being conducted under
the guidance of Dr. Deborah Feltz of Michigan State University (355-4732).

If you elect to be a part of the study, you will be randomly assigned to one of two study
groups. You will be asked to either continue with your normal medication treatment for
depression or continue with your medication treatment and take part in an exercise
training program.

Ifyou are randomly assigned to the medication only group, you will be asked to continue
your current medication treatment. Furthermore, you will be asked to complete a series
of questionnaires at study entry, 3, 6, and 9 weeks later. These questionnaires are related
to your thoughts, feelings, and symptoms of depression and will take approximately 15-
20 minutes to complete.

Ifyou are randomly assigned to the medication and exercise group, you will be asked
continue your current medication treatment as well as to join a moderate intensity
exercise training group. This group will meet twice per week for 45 minutes each
session. You will also be asked to complete one 45-min exercise session per week on
your own at home. At study entry, 3, 6, and 9 weeks later you will be asked to complete
a series of questionnaires related to your thoughts, feelings, and symptoms of depression.
This series of questionnaires will take approximately 15-20 minutes to complete.
Furthermore, you will be asked to rate your perceived exertion and level of enjoyment for
each exercise session as well as your mood immediately prior to, immediately following,
and for the 15 minutes after each exercise training session.

All participants who complete the entire 9-week study will receive $25.00 for their
participation. Study participants will receive the $25.00 compensation at the end of the
study in one payment. Participants who do not complete the entire 9-week study will not
be compensated for their involvement.

The primary foreseeable risk to participants in this research study is the mild physical
discomfort that can be associated with moderate physical activity.

If you are injured as a result of your participation in this research project, Michigan State
University will provide emergency medical care if needed. If the injury is not caused by
the negligence of MSU you are personally responsible for the expenses of this medical
care and any other medical expenses incurred as a result of this injury.

76

You are free to withdraw from participating in the study at any time that you feel
uncomfortable with the procedure without being penalized in any way. You may refuse
to answer certain questions or may discontinue the study at any time without penalty.

If you elect to participate, your responses will be kept conﬁdential and only the research
investigators will have access to the data. Only group data will be reported and your
name will not be associated with the data in any way. Your privacy will be protected to
the maximum extent allowable by law.

Ifyou elect to participate, you will be asked to keep conﬁdential the identities of other
study participants.

If you have any questions regarding the study, you are encouraged to ask them at any
time, or to contact Dr. Deborah F eltz (355-4732) at any time.

If you have any questions about your rights as a participant in this research, or if you feel

you have been placed at risk, you can contact the Chair of the University Committee for
Research Involving Human Subjects (UCRIHS): Dr. Ashir Kumar,M.D. at 355-2180.

Your signature below indicates your voluntary decision to participate in this study:

 

Participant Signature

 

Date

77

APPENDIX B

Demographic Questionnaire

78

Please answer each of the questions below by either ﬁlling in the blank or circling the
appropriate answer.

Ethnicity Caucasian
African American
American Indian
Asian American
Latino
Other

 

How old were you when you experienced your FIRST diagnosed episode of depression?

 

How old were you when you experienced your ﬁrst self-diagnosed episode of
depression?

 

How long has your CURRENT episode of depression lasted?

 

How many times have you been hospitalized for depression?

 

List the medication(s) that you currently take for your depression:

 

 

How long have you been taking the above listed medicine(s):

 

List other types of therapy you have tried in the past for your depression such as
counseling, ECT therapy, etc.:

 

 

Does anyone else in your family have a history of depression? Yes No
If yes, who?

 

Do you have a regular menstrual cycle? Yes No

If you do not have a regular menstrual cycle, are you post-menopausal? Yes No

 

Please list any current physical health problems.

 

79

APPENDIX C

Exercise Program Readiness Questionnaire

8O

Michigan State University
Human Energy Research Laboratory
Exercise Program/Testing Readiness Questionnaire

Every participant must ﬁll out this questionnaire and sign a release before he/she will be allowed to
participate in an exercise program and/or exercise testing activity sponsored by the Human Energy
Research Laboratory. If you are under 18 years of age, a parent or legal guardian must sign the form on
your behalf. Ifyou are a man (woman) over 40 (50), or under 40 (50) and physically inactive, your
physician must also sign this form indicating your ability to participate in the exercise program or test
indicated.

 

 

 

 

Name Phone Date
Address Date of Birth
Ht Wt
Yes No 1. Has your doctor ever said you have heart trouble?
Yes No 2. Have you ever had chest pain or heavy pressure in your chest

as a result of exercise, walking, or other physical activity, such
as climbing a ﬂight of stairs? (Note: This does not include normal
out-of-breath feeling that results from vigorous exercise)

Yes No 3. Do you often feel faint or experience severe dizziness?
Yes No 4. Has a doctor ever told you that you have high blood
pressure or diabetes?
Yes No 5. Have you ever had a real or suspected heart attack
or stroke?
Yes No 6. Do you have nay physical condition, impairment or disability

including any joint or muscle problem, that should be
considered before you undertake an exercise program?

Yes No 7. Have you ever taken medication to reduce your blood
pressure or cholesterol levels?

Yes No 8. Are you excessively overweight?

Yes No 9. Is there any good physical reason not mentioned here
why you should not follow an exercise program even
if you wanted to?

Yes No 10. Are you over age 40, or not accustomed to vigorous

exercise?

If you answered YES to one or more questions, and if you have not recently done so, consult with your
physician BEFORE entering an exercise program or participating in an exercise test. After medical
evaluation or consultation, have your physician sign this form indicating your suitability for the following
activity:

 

 

 

 

Signature of Physician Date Phone

81

APPENDIX D

Beck Depression Inventory-II

82

ID#

 

BDI-II

This questionnaire consists of 21 groups of statements. Please read each group of
statements carefully, and then pick out the one statement in each group that best
describes the way you have been feeling during the past two weeks, including today.
Circle the number beside the statement you have picked. If several statements in the
group seem to apply equally well, circle the highest number for that group. Be sure that
you do not choose more than one statement for any group, including Item 16 (Changes in
Sleeping Pattern) or Item 18 (Changes in Appetite).

1. Sadness
0 I do not feel sad.
1 I feel sad much of the time.
2 I am sad all the time.
3 I am so sad or unhappy that I can’t stand it.

2. Pessimism
O I am not discouraged about my ﬁxture.
1 I feel more discouraged about my ﬁxture than I used to be.
2 1 do not expect things to work out for me.
3 I feel my future is hopeless and will only get worse.

3. Past Failure
0 I do not feel like a failure.
1 I have failed more than I should have.
2 As 1 look back, 1 see a lot of failures.
3 I feel I am a total failure as a person.

4. Loss of Pleasure
0 I get as much pleasure as I ever did from the things I enjoy.
1 I don’t enjoy things as much as I used to.
2 I get very little pleasure from the things 1 used to enjoy.
3 I can’t get any pleasure from the things 1 used to enjoy.

5. Guilty Feelings
0 I don’t feel particularly guilty.
1 I feel guilty over many things I have done or should have done.
2 I feel quite guilty most of the time.
3 I feel guilty all of the time.

83

6. Punishment Feelings

I don’t feel I am being punished.
I feel I may be punished.

I expect to be punished.

I feel I am being punished.

WN—‘O

7. Self-Dislike
0 I feel the same about myself as ever.
1 I have lost conﬁdence in myself.

2 I am disappointed in myself.
3 I dislike myself.

8. Self-Criticalness
0 I don’t criticize or blame myself more than usual.
1 I am more critical of myself than I used to be.
2 I criticize myself for all of my faults.
3 I blame myself for everything bad that happens.

9. Suicidal Thoughts or Wishes
0 I don’t have any thoughts of killing myself
1 I have thoughts of killing myself, but I would not carry them out.
2 I would like to kill myself
3 I would kill myself if 1 had the chance.

10. Crying
0 I don’t cry anymore than I used to.
1 I cry more than I used to.
2 I cry over every little thing.
3 I feel like crying, but I can’t.

I 1. Agitation .
0 I am no more restless or wound up than usual.
1 I feel more restless or wound up than usual.
2 I am so restless or agitated that it’s hard to stay still.
3 I am so restless or agitated that I have to keep moving or doing something.

12. Loss of Interest
0 I have not lost interest in other people or activities.
1 I am less interested in other people or things than before.
2 I have lost most of my interest in other people or things.
3 It’s hard to get interested in anything.

84

13. Indecisiveness
O I make decisions about as well as ever.
1 I ﬁnd it more difﬁcult to make decisions than usual.
2 I have much greater difﬁculty in making decisions than I used to.
3 I have trouble making any decisions.

14. Worthlessness
0 I do not feel I am worthless.
1 I don’t consider myself as worthwhile and useful as I used to.
2 I feel more worthless as compared to other people.
3 I feel utterly worthless.

15. Loss of Energy
0 I have as much energy as ever.
1 I have less energy than I used to have.
2 I don’t have enough energy to do very much.
3 I don’t have enough energy to do anything.

16. Changes in Sleeping Pattern
0 I have not experienced any change in my sleeping pattern
1a I sleep somewhat more than usual.
1b I sleep somewhat less than usual.
2a I sleep a lot more than usual.
2b 1 sleep a lot less than usual.
3a I sleep most of the day.
3b I wake up 1-2 hours early and can’t get back to sleep.

17. Irritability
0 I am no more irritable than usual.
1 I am more irritable than usual.
2 I am much more irritable than usual.
3 I am irritable all the time.

18. Changes in Appetite
0 I have not experienced any change in my appetite.
la My appetite is somewhat less than usual.
1b My appetite is somewhat greater than usual.
2a My appetite is much less than before.
2b My appetite is much greater than before.
3a I have no appetite at all.
3b I crave food all the time.

85

19. Concentration Difﬁculty
0 I can concentrate as well as ever.
1 I can’t concentrate as well as usual.
2 It’s hard to keep my mind on anything for very long.
3 I ﬁnd I can’t concentrate on anything.

20. Tiredness or Fatigue
0 I am no more tired or fatigued than usual.
1 I get more tired or fatigued more easily than usual.
2 I am too tired or fatigued to do a lot of the things I used to do.
3 I am too tired or fatigued to do most of the things I used to do.

21. Loss of Interest in Sex
0 I have not noticed any recent change in my interest in sex.
1 I am less interested in sex than I used to be.
2 I am much less interested in sex now.
3 I have lost interest in sex completely.

86

APPENDIX E

Depression Coping Self-Efﬁcacy Scale

87

The following measure describes coping activities that may be helpful in treating the
symptoms of depression. Under the column headed CONFIDENCE, mark how
conﬁdent you are that you could do each activity using a number ﬁ'om O to 10. These
numbers mean that you are not at all conﬁdent or sure (0) to completely conﬁdent or sure
(10) that you can do each of these things listed. You may use any number from 0-10.

0 l 2 3 4 5 6 7 8 9 10
Not conﬁdent Moderately conﬁdent Conﬁdent

I am this conﬁdent that I will be able to do the following things that may relive or

prevent the symptoms of depression:
Conﬁdence (Mark 0-10)

l

Tell others how I feel in a socially acceptable manner

Be aware of my behavior and how it affects others

Refuse requests of others when I do not wish to do something
that someone else wants me to do, including authority ﬁgures
and strangers

Go to bed and get up at the same time every day

Plan pleasant things to do for my free time

Limit naps to 20-30 minutes during the day

Ask for help when I am having trouble understanding
something because I am not concentrating well (like income
tax, legal documents, etc.)

Eat four servings of fruits and vegetables daily

Drink 6 to 8 glasses of water daily

Recognize when I am blaming myself for my symptoms and
try to stop

Engage in some sort of creative activity like writing, reading,
drawing, playing music, or working on projects

Get together with at least one very close person when I am
feeling lonely

88

0 1 2 3 4 5 6 7 8 9 10
Not conﬁdent Moderately conﬁdent Conﬁdent

I am this conﬁdent that I will be able to do the following things that may relive or

prevent the symptoms of depression:
Conﬁdence (Mark 0-10)

I

Get up and do something relaxing if I cannot sleep, before
trying again

Question whether it is reasonable to think this way each time
I think about myself in a negative way or assume that I am no good

Take a bath or do some other soothing activity before bedtime
Take medication the way my doctor recommends
Exercise or do some active thing every day

Be aware of when I am thinking about myself in a negative
way or assuming that I am no good

Laugh and try to ﬁnd humor in my situation, in spite of
my problem

Challenge the thought that suicide is the only way I can deal
with my problems

Attempt to understand why I am anxious when I have anxiety

Keep a journal describing my mood or how I feel emotionally
each day

Meditate or do relaxation exercises at least once a day

Become aware of those feelings that bother me so I can work
on not letting them bother me

89

APPENDIX F

Response Styles Questionnaire

9O

Almost
Never

E]
El

Sometimes

C1
C1

Responses to Depression

People think and do many different things when they feel depressed. Please read each of the items below
and indicate whether you never, sometimes, often, or always think or do each one when you feel down, sad,
or depressed. Please indicate what you generally do, not what you think you should do.

Often

E]
El

Almost
Always

C]
D

91

think about how alone you feel

think “I won’t be able to do my
job/work because I feel so
badly

think about your feelings of
fatigue and achiness

think about how hard it is
to concentrate

try to ﬁnd something positive
in the situation or
something you learned

think “I’m going to do something
to make myself feel better”

help someone else with something
in order to distract yourself

think about how passive and
unrnotivated you feel

remind yourself that these
feelings won’t last

analyze recent events to try
to understand why you are
depressed

think about how you don’t seem
to feel anything anymore

think “Why can’t I get going?"

think “Why do I always react
this way?”

go to a favorite place to get your
mind off your feelings

go away by yourself and think
about why you feel this way

Almost
Never

Cl

0

Almost
Sometimes Often Always

D C] C] write down what your are thinking
about and analyze it

C] D CI do something that has made you
feel better in the past

Cl C] [I think “I’m going to go out
and have some fun”

concentrate on your work

think “Why do I have problems
other people don’t have?”

think about how sad you feel

think about all your shortcomings,
failings, faults, mistakes

do something you enjoy

think about how you don’t feel
up to doing anything

C] 0 CI do something fun with a friend

C] D D analyze your personality to try to
understand why you are depressed

C] E] El go someplace alone to think
about your feelings

C] E] El think about how angry you are
with yourself

listen to sad music

isolate yourself and think about
the reasons why you feel sad

C] E] El try to understand yourself by
focusing on your depressed feelings

92

APPENDIX G

Rating of Perceived Exertion Scale

93

Perceived Exertion

6

10

11

12

13

14

15

16

17

18

19

20

Very, very light

Very light

Fairly light

Somewhat hard

Hard

Very hard

Very, very hard

94

APPENDIX H

Rating of Mood and Enjoyment of Exercise Scales

95

Study Week Session ID #

1. Please rate your current mood on the scale below. You should focus on how you feel right now

for the time indicated.

Immediater prior to exercise session:

Very negative, Neutral
Sad, Down
-3 -2 -1 0

Immediater following the exercise session:

Very negative, Neutral
Sad, Down
-3 -2 -1 0

5 minutes following the exercise session:

Very negative, Neutral
Sad, Down
-3 -2 -l 0

10 minutes following the exercise session:

Very negative, Neutral
Sad, Down
-3 -2 -1 0

15 minutes following the exercise session:

Very negative, Neutral
Sad, Down

-3 -2 -l 0
11. Rating of enjoyment

Very good,
Happy. Upbeat

3

Very good.
Happy. Upbeat

3

Very good,
Happy, Upbeat

3

Very good.
Happy. Upbeat

3

Very good,
Happy. Upbeat

3

Using the scale below, please rate how much you enjoyed the exercise session you just completed

Not at all Somewhat

-3 -2 -l 0

111. Rating of Perceived Exertion (RPE)

Please rate your average RPE for the exercise session:

96

Very much so

3

BIBLIOGRAPHY

97

BIBLIOGRAPHY

American Psychiatric Association (1994). Diagnostic and statistical manual of
mental disorders (4th ed). Washington, DC: American Psychiatric Association.

 

Arent, S. M., Landers, D. M., & Etnier, J. L. (2000). The effects of exercise on
mood in older adults: A meta-analytic review. Journ_al of Aging and Physical Activity, 8,
407-430.

Babyak, M., Blumenthal, J. A., Herman, S., Khatri, P., Doraiswamy, M., Moore,
K., Craighead, W. E., Baldewicz, T. T., & Krishnan, K. R. (2000). Exercise treatment for
major depression: Maintenance of therapeutic beneﬁt at 10 months. Psychesomatie
Medicine, 62, 633-638.

Bahrke, M.S., & Morgan, W. P. (1978). Anxiety reduction following exercise
and meditation. Cognitive Therapy Research, 2, 323-333.

Bandura, A. (1977). Self-efﬁcacy: Toward a unifying theory of behavioral
change. Psychelogical Review, 84, 191-215.

Bandura, A. (1997). Self-efﬁcecy: The exercise of control. New York, NY:
W.H. Freeman and Company.

Bandura, A., Pastorelli, C., Barbaranelli, C., & Caprara, G. V. (1999). Self-
efﬁcacy pathways to childhood depression. Journal of Personality and Social

Psychology, 76, 258-269.

Bandura, A., Taylor, C. B., Williams, S. L., Mefford, I. N., & Barchas, J. D.
(1985). Catecholamine secretion as a ﬁinction of perceived coping self-efﬁcacy. Journal
ef Consulting and Clinicel Psychology, 53, 406-414.

Bastone, E. C., & Kerns, R. D. (1995). Effects of self-efﬁcacy and perceived
social support on recovery-related behaviors after coronary artery bypass graft surgery.
Annals of Behaviorel Medicine. 17. 324-330.

Beck, A. T., Steer, R. A., & Brown, K. (1996). Beck depression inventog, 2""

edition manual. SanAntonio, TX: Harcourt Brace.

Beniamini, Y., Rubenstein, J. J ., Zaichkowsky, L. D., & Crim, M. C. (1997).
Effects of high-intensity strength training on quality-of-life parameters in cardiac
rehabilitation patients. Americen Joumel of Cardiology, 80, 841-846.

98

Berger, B. G., & Owen, D. R. (1998). Relation of low and moderate intensity
exercise with acute mood change in college joggers. Perceptual and Motor Skill§L87,
611-621.

Berger, B. G., & Owen, D. R. (1983). Mood alteration with swimming:
Swimmers really do “feel better.” Psychosomatic Medicine. 45. 425-431.

Berger, B. G., & Owen, D. R. (1988). Stress reduction and mood enhancement in
four exercise modes: Swimming, body conditioning, hatha yoga, and fencing. Research

Quagerly, 59, 145-159.

Berger, B. G., Owen, D. R., Motl, R. W., & Parks, L. (1998). Relationship
between expectancy of psychological beneﬁts and mood alteration in joggers.
International Journal of Sport Psychology, 29, 1-16.

Biondi, M, & Picardi, A. (1999). Psychological stress and neuroendocrine
function in humans: The last two decades of research. Psychotherapy end
Psychosometics. 68, 114-150.

Blue, F . R. (1979). Aerobic running as a treatment for moderate depression.
Perceptual end Motor Skills. 48. 228.

Blumenthal, J. A., Babyak, M. A., Moore, K. A., Craighead, W. E., Herman, S.,
Khatri, P., Waugh, R., Napolitano, M. A., Forrnan, L. M., Appelbaum, M., Doraiswamy,
M., & Krishnan, K. R. (1999). Effects of exercise treinipg on older petients with m_ajo_r

depression. Archives of Internal Medicine, 159, 2349-2356.

Blumenthal, J. A., Williams, R. S., Needels, T. L., & Wallace, A. G. (1982).
Psychological changes accompanying aerobic exercise in healthy middle-aged adults.
Psychosomatic Medicine. 44. 529-536.

Borg, G. (1982). The rating of perceived exertion scale. Medicine ml Science in
Sports and Exercise. 14, 377-387.

Bortz, W. M, Angwin, P., & Mefford, I. N (1981). Catecholamines, dopamine,
and endorphin levels during extreme exercise. The New ErygLand Joum_al of Medicine.
ﬂ, 466-467.

Brown, S. W., Welsh, M. C., Labbe, E. E., Vitulli, W. F ., & Kulkarni, P. (1992).
Aerobic exercise in the psychological treatment of adolescents. Perceptual and Motor

Skills, 74, 555-560.

Burns, D., & Nolen-Hoeksema, S. K. (1991). Coping styles, homework
assignments and the effectiveness of cognitive-behavioral therapy. .10qu] ef Consplting
eng Clinicel Psychology, 59, 305-311.

99

Byrne, A., & Byrne, D. G. (1993). The effect of exercise on depression, anxiety
and other mood states: A review. Journel of Psychosometic Reseerch. 37. 565-574.

Carr, D. B., Bullen, B. A., Skinrar, G., Arnold, M. A., Rosenblatt, M., Beitins, I.
2., Martin, J. B., & McArthur, J. W. (1981). Physical conditioning facilitates the
exercise-induced secretion of Beta-endorphin and Beta-lipotropin in women. The New

Englend Jeernal of medicine. 305. 560-563.

Checkley, S. (1996). The neuroendocrinology of depression and chronic stress.
British Medical Bulletin. 52, 597-617.

Craft, L. L., & Landers, D.M. (1998). The effect of exercise on clinical
depression and depression resulting from mental illness: A meta-analysis. Journal of

Sport and Exercise Psychology, 20, 339-357.

DeVries, H. A. (1968). Immediate and long term effects of exercise upon resting
muscle action potential. Sports Medicine end Physicel Fitness. 8. 1-11.

DeVries, H. A. (1981). Tranquilizer effects of exercise: A critical review. 111:
Phyeieien end Sports Medicine. 9. 46-55.

DiLorenzo, T. M., Bargman, E. P., Stucky-Ropp, R., Brassington, G. S., Frensch,
P. A., & LaFontaine, T. (1999). Long-terrn effects of aerobic exercise on psychological
outcomes. Preventive Medicine. 28. 75-85.

_ Dimeo, F. Baurer, M., Varahram, I., Proest, G., & Halter, U. (2001). Beneﬁts
from aerobic exercise in patients with major depression: A pilot study. British Journal of

Sports Medicine, 35, 114-117.

Dishman, R. K. (1997). The norepinephrine hypothesis. In W. P. Morgan (Ed),
Physical activity and mental health. Washington, DC: Taylor & Francis.

Doyne, E. J., Chambless, D. L., & Beutler, L. E. (1983). Aerobic exercise as a
treatment for depression in women. Belgivior Therapy, 14, 434-440.

Doyne, E. J., Ossip-Klein, D. J., Bowman, E. D., Osborn, K. M., McDougall-
Wilson, I. B., & Neimeyer, R. A. (1987). Running versus weight lifting in the treatment
of depression. Joemel of Consulting end Clinical Psychology, 55, 748-754.

Dunn, A. L., Reigle, T. G., Youngstedt, S. D., Armstrong, R. B., & Dishman, R.
K. (1996). Brain norepinephrine and metabolites alter treadmill training and wheel
running in rats. Medicine end Science in Sports Mi Exercise. 28. 204-209.

Dunn, A. L., Trivedi, M. H., & O’Neil, H. A. (2001). Physical activity dose-
response effects on outcomes of depression and anxiety. Medicine and Science in Sporte
end Exercise, 33, 5587-5597.

100

Dyer, J. B., & Crouch, J. G. (1988). Effects of running and other activities on

moods. Perceptual and Motor Skills, 67, 43-50.
Ebert, M. H., Post, R. M., & Goodwen, F. K. (1972). Effects of physical activity

on urinary MHPG excretion in depressed patients. Lancet 2, 766.

 

Ewart, C. K. (1995). Self-efﬁcacy and recovery from heart attack: Implications
for a social cognitive analysis of exercise and emotion. In J. E. Maddux (Ed), 891i
effrceey, edaptation, and adjustment: Theory. reseerch. and application. New York, NY:
Plenium Press.

Ewart, C. K., Stewart, K. J., Gillilan, R. E., & Kelemen, M. H. (1986). Self-
effrcacy mediates strength gains during circuit weight training in men with coronary

artery disease. Medicine and Science in Sports and Exercise, 18, 531-540.

Farrell, P. A., Gates, W. K., & Maksud, M. G. (1982). Increases in plasma B-
endorphin, B-lipotmpin immunoreactivity after treadmill running in humans. Journal of

Appliﬁ Physiology, 52, 1245-1249.

Flory, J .D., & Holmes, D. S. (1991). Effects of an acute bout of aerobic exercise
on cardiovascular and subjective responses during subsequent cognitive work. Journal of

Psychosomatic Research, 35, 225-230.

Fox, K. R. (1999). The inﬂuence of physical activity on mental well-being.
Public Health Nutrition. 2, 411-418.

Fremont, J ., & Craighead, L. W. (1987). Aerobic exercise and cognitive therapy
in the treatment of dysphoric moods. Cognitive Therapy and Reseerch. 11, 241-251.

Gerin, W., Litt, M. D., Deich, J., & Pickering, T. G. (1996). Self-efﬁcacy as a
component of active coping effects on cardiovascular reactivity. Journal of
Peychosomatic Reseerch 40, 485-494.

Gleser, J., & Mendelberg, H. (1990). Exercise and sport in mental health: A
review of the literature. Iereel Journal of Psychiatgi and Releted Sciences. 27, 99-112.

Greist, J. R, Klein, M. H, Eischens, R. R., Faris, J., Gurman, A. S., & Morgan,
W. P. (1979). Running as treatment for depression. Comprehensive Psychietry. 20, 41-
54.

Gullette, C. D., & Blumenthal, J. A. (1996). Exercise therapy for the prevention
and treatment of depression. Journel of Prectitgl Psychiatg and Behavioral Health, 5,
263-271.

Hansen, C. J., Stevens, L. C., & Coast, J. R. (2001). Exercise duration and mood
state: How much is enough to feel better? H_eelth Psychology, 20, 267-275.

101

Hardy, C. J., & Rejeski, W. J. (1989). Not what, but how one feels: The
measurement of affect during exercise. Journal of Spoﬂnd Exercise Psycholo 11,
304-317.

Hatz, G. W., Wallace, W. L., & Cayton, T. G. (1982). Effect of aerobic
conditioning upon mood in clinically depressed men and women: A preliminary
investigation. Perceptual and Motor SkillsJS. 1217-1218.

Hedges, L. V., & Olkin, I. (1985). Statistical methods for meta-analysis. New
York: Academic Press.

Hill, A. B. (1965). The environment and disease: Association or causation?
Preceedings of the Royel Society of Medicine. 58. 295-300.

Hobson, M. L., & Rejeski, W. J. (1993). Does the dose of acute exercise mediate
psychophysiological responses to mental stress? Journal of Sport and Exercise

Peychology, 15, 77-87.

Holahan, C. K., & Holahan, C. J. (1987). Self-efﬁcacy, social support, and
depression in aging: A longitudinal analysis. Journel of Gerontology, 42, 65-68.

Jacobs, B. L. (1994). Serotonin. motor ectivity yd depression-related disorders.
Americen Scientist. 82. 456-463.

Jasnowski., M. L., Holmes, D. S., & Banks, D. L. (1988). Changes in personality
associated with changes in aerobic and anaerobic ﬁtness in women and men. Journal of
Peychosematic Reseerch. 32. 273-276.

Johnson, L. D., & Miller, S. D. (1994). Modiﬁcation of depression risk factors: A
solution-focused approach. Psychotherapy, 31, 244-253.

Johnsgard, K. W. (1989). The exercise prescription fcmnxiety end depression.
New York: Plenum Publishing.

Just, N., & Alloy, L. B. (1997). The response styles theory of depression: Tests
and an extension of the theory. Journel of Abnormal Psycholggye 106, 221-229.

Kavanagh, D. J., & Wilson, P. H. (1989). Prediction of outcome with a group
version of cognitive therapy for depression. Beheviour Reseerchend Therapy, 27, 333-
347.

Kavanaugh, T., Shephard, R. T., Tuck, J. A., & Qureshi, S. (1977). Depression
following myocardial infarction: The effect of distance running. Annels of the New Yer

Agdemy ef Science, 801, 1029-1036.

102

Kennedy, M. M., & Newton, M. (1997). Effect of exercise intensity on mood in
step aerobics. Journel of Sports Medicine end Physicel Fitness. 37. 200-204.

Klein, M. H, Greist, J. H, Gurman, A. S., Neimeyer, R. A., Lesser, D. P.,
Bushnell, N. J., & Smith, R. E. (1985). A comparative outcome study of group

psychotherapy vs. exercise treatments for depression. Internationel Joumel of Menta_l
Health 13, 148-177.

 

Landers, D. M., & Arent, S. M. (2001). Physical activity and mental health. In R.
N. Singer, H. A. Hausenblaus, & C. M. Janelle (Eds), Handbook of sport psychology
(2mI edition). New York, NY: John Wiley and Sons.

Landers, D. M., & Petruzzello, S. (1994). Physical activity, ﬁtness, and anxiety.
In C. Bouchard et al. (Eds), Physical activity. ﬁtness. end hem. Champaign, IL:
Human Kinetics.

Leith, L. M. (1994). Foundetions of exercise end mentel heelt_h. Morgantown,
WV: Fitness Information Technology.

Litt, M. D., Nye, C., & Shafer, D. (1995). Preparation for oral surgery:
Evaluating elements of coping. Journal of Behavioral Medicine. 18. 435-459.

Lyubomirsky, S., & Nolen-Hoeksema, S. (1993). Self-perpetuating properties of
depressive rumination. Journel of Personality and Soﬂl Psycholo 65, 339-349.

Lyubomirsky, S., & Nolen-Hoeksema, S. (1995). Effects of self-focused
rumination on negative thinking and interpersonal problem-solving. Journal of
Persenality and Social Psychology, 69, 176-190.

Maroulakis, E., & Zervas, Y. (1993). Effects of aerobic exercise on mood of
adult women. PerceptuLand Motor Skills. 76, 795-801.

Martinsen, E. W. (1987). The role of aerobic exercise in the treatment of
depression. Stress Medicine. 3, 93-100.

Martinsen, E. W. (1990). Beneﬁts of exercise for the treatment of depression.
Sports Medicine. 9. 380-389.

Martinsen, E. W. (1993). Therapeutic implications of exercise for clinically
anxious and depressed patients. Intemetionel Joumel of Sport Psychology, 24, 185-199.

Martinsen, E. W. (1994). Physical activity and depression: Clinical experience.

Aete Psychietrica Scandinavica, 377, 23-27.

103

Martinsen, E. W., Hoffart, A., & Solberg, O. (1989). Comparing aerobic and
nonaerobic forms of exercise in the treatment of clinical depression: A randomized trial.

Comprehensive Psychiatg, 30, 324-331.

Martinsen, E. W., Medhus, A., & Sandvik, L. (1985). Effects of aerobic exercise
on depression: A controlled study. British Medical Journal. 291. 109.

 

Martinsen, E. W., Strand, J ., Paulsson, G., & Kaggestad, J. (1989). Physical
ﬁtness levels in patients with anxiety and depressive disorders. International Journal of

Sports Medicine, 10, 58-61.

McAuley, E. (1992). Understanding exercise behavior: A self-efﬁcacy
perspective. In G. C. Roberts (Ed), Motivetion in sport end exercise. Champaign, IL:
Human Kinetics.

McAuley, E., & Coumeya, K. S. (1992). Self-efﬁcacy relationships with
affective and exertion responses to exercise. Journel of Applied Sociel Psycholo 22,
312-326.

McAuley, E., Lox, C., & Duncan, T. E. (1993). Long-terrn maintenance of
exercise, self-efﬁcacy, and physiological change in older adults. Journel of Gerontology;

Psychological Sciences, 48, 218-224.

McCann, I. L., & Holmes, D. S. (1984). Inﬂuence of aerobic exercise on
depression: A controlled study. Journel of Personality and Sociel Psychology, 46, 1142-
1147.

McGowan, R. W., Pierce, E. F ., & Jordan, D. (1991). Mood alterations with a
single bout of physical activity. Perceptual end Motor Skills. 72, 1203-1209.

McGowan, R. W., Pierce, E. F. Eastman, N. Tripathi, H. L., Dewey, T., & Olson,
K. (1993). Beta-endorphins and mood states during resistance exercise. Perceptual and
Motor Skills. 76, 376-378.

McGowan, R. W., Talton, B. J., & Thompson, M. (1996). Changes in scores on
the Proﬁle of Mood States following a single bout of physical activity: Heart rate and
changes in affect. Perceptual and Motor Skills. 83, 859-866.

McIntyre, C. W., Watson, D., & Cunningham, A. C. (1990). The effects of social
interaction, exercise, and test stress on positive and negative affect. Bulletin of the
Psychonomic Societij. 141-143.

McMillan, J. L., Stone, M. H, Sartin, J ., Keith, R., Marple, D., Brown, C., &

Lewis, R. D. (1993). 20-hour physiological responses to a single weight-training session.
Journel of Strength and Conditioning Reseerch. 7, 9-21.

104

McNeil, J. K., LeBlanc, E. M., & Joyner, M. (1991). The effect of exercise on
depressive symptoms in the moderately depressed elderly. Psychology and Aging, 6,
487-488.

Mirin, S. M., & Sederer, L. I. (1994). Mental health care: Current realities, ﬁrture
directions. Psychietric Ouerterly. 65, 161-175.

Morgan, W. P. (1969). A pilot investigation of physical working capacity in
depressed and nondepressed males. Reseerch (menerly. 40. 859-861.

Morgan, W. P. (1970). Physical working capacity in depressed and non-
depressed psychiatric females: A preliminary study. America Corrective Therepy

Jeumel, 24, 14-16.

Morgan, W. P. (1985). Affective beneﬁcience of vigorous physical activity.
Medicine end Science in Sports and Exercise. 17. 94-100.

Morgan, W. P. (1988). Exercise and mental health. In R. K. Dishman (Ed),
Exercise adherence: Its impect on public heeltL Champaign, IL: Human Kinetics.

 

Morrow, J ., & Nolen-Hoeksema, S. (1990). Effects of responses to depression on
the remediation of depressive affect. Journel: of Personelity and Social Psychelegy, 58,
5 19-527.

Moses, J ., Steptoe, A., Mathews, A., & Edwards, S. (1989). The effects of
exercise training on mental well-being in the normal population: A controlled trial.
Journal of Psychosomatic Reseerch. 33, 47—61.

Murray, C. J ., & Lopez, A. D. (1996). Evidence-based health policy lessons
from the Global Burden of Disease Study. Science. 274, 740-743.

Mutrie, N. (2000). The relationship between physical activity and clinically-
deﬁned depression. In S. J. H. Biddle, K. R. Fox, & S. H. Boutcher (Eds), Physical

activity and psychological well-being. London: Routledge.

National Institutes of Mental Health (2001). The numbers count: Mental
disorders in America. Retrieved December 20. 2001. from http://www.nimh.go_v.

Nolen-Hoeksema, S. (1991). Responses to depression and their effects on the
duration of depressive episodes. Journel of Abnormel Psychology, 100, 569-582.

Nolen-Hoeksema, S. (1998). Ruminative coping with depression. In J.

Heckhausen and C. S. Dweck (Eds), Motivetion end self-regplation across the life §p_ap.
New York, NY: Cambridge University Press.

105

Nolen-Hoeksema, S., & Davis, C. G. (1999). “Thanks for sharing that”:
Ruminators and their social support networks. Journel of Personality and Social

Psychology, 77, 801-814.

Nolen-Hoeksema, S., & Morrow, J. (1991). A prospective study of depression
and posttraumatic stress symptoms after a natural disaster: The 1989 Lorna Prieta
earthquake. Journal of Personality and Sociel Psycholo 61, 115-121.

Nolen-Hoeksema, S., Morrow, J., & Fredrickson, B. L. (1993). Response styles
and the duration of episodes of depressed mood. Journal of Abnormel Psychology, 102,
20—28.

Nolen-Hoeksema, S., Parker, L., & Larson, J. (1994). Ruminative coping with
depressed mood following loss. Joumei of Persopelity end Sociel Psychology, 67, 92-
104.

North, T. C., McCullagh, P., & Tran, Z. V. (1990). Effects of exercise on
depression. Exercise end Sport Science Reviews. 18. 379-415.

Olfson, M., Marcus, S. C., Druss, B., Elinson, L., Tanielian, R., & Pincus, H. A.
(2002). National trends in the outpatient treatment of depression. Journal of the
American Medical Association 287, 203-209.

 

Ozer, E. M., & Bandura, A. (1990). Mechanisms governing empowerment

effects: A self-efﬁcacy analysis. Journal of Personality and Social Psyehelogy, 58, 472-
486.

Parﬁtt, G., Eston, R., & Connolly, D. (1996). Psychological affect at different
ratings of perceived exertion in high-and low-active women: A study using a production
protocol. Perceptual and Motor Skills. 82, 1035-1042.

Perraud, S. (2000). Development of the Depression Coping Self-Efﬁcacy Scale
(DCSES). Archives of chhiepric Nursing, 14, 276-284.

Peterson, C., & Seligman, M. E. P. (1984). Causal explanations as a risk factor
for depression: Theory and evidence. Psychological Review. 91 , 347-3 74.

Petruzzello, S. J., Jones, A. C., & Tate, A. K. (1997). Affective responses to
acute exercise: A test of opponent-process theory. Joumel of Sports Medicine and

Phyeical Fitness, 37, 205-212.

Post, R. M., Kotin, J., Goodwin, F. K., & Gordon, E. K. (1973). Psychomotor
activity and cerebrospinal ﬂuid amine metabolites in affective illness. Americen Joemel

efPsychiatgi, 130, 67-72.

106

 

Preskom, S. H. (1999). Outpatient management of depression: A guide for the
pregiener (2"d edition). Caddo, OK: Professional Communications, Inc.

Raglin, J. S. (1990). Exercise and mental health: Beneﬁcial and detrimental
effects. Sperts Medicine-9. 323-329.

Raglin, J. S., & Morgan, W. P. (1985). Inﬂuence of exercise and quiet rest on
state anxiety and blood pressure. Medicine and Science in Sports and Exercise. 19. 456-
463.

Ransford, C. P. (1982). A role for amines in the antidepressant effect of exercise:
A review. Medicine end Science in Sports end Exercise. 14. 1-10.

Roth, D. L. (1989). Acute emotional and psychophysiological effects of aerobic
exercise. Psychophysiology, 25, 593-602.

Sanderson, W. C., Rapee, R. M., & Barlow, D. H. (1989). The inﬂuence of an
illusion of control on panic attacks induced via inhalation of 5.5% carbon dioxide-
enriched air. Archives of General Psychiatgg, 46, 157-162.

Sharp, M. W., & Reilley, R. R. (1975). The relationship of aerobic physical
ﬁtness to selected personality traits. Journal of Clinicel Psychology, 113, 23.

Simons, A. D., McGowan, C. R., Epstein, L. H, Kupfer, D. J., & Robertson, R J.
(1985). Exercise as a treatment for depression: An update. Clinicel Psychology Review.
S, 553-568.

Singh, N. A., Clements, K. M., & Fiatarone, M. A. (1997). A randomized
controlled trial of progressive resistance training in depressed elders. Journal of

gerontology, 52, M27-M35.

Solomon, R. L. (1980). The opponent-process theory of acquired motivation: The
costs of pleasure and the beneﬁts of pain. American Psychologist, 35, 691-712.

Stahl, S. M. (1996). Essential psychopharmacology: Neuroscientiﬁc basis and
practical applications. New York, NY: Cambridge University Press.

Stern. M., & Cleary, P. (1981). National exercise and heart disease project:
Psychosocial changes observed during a low-level exercise program. Archives ef
Intemel Medicine. 141. 1463-1467.

Stephens, T. (1988). Physical and mental health in the United States and Canada:
Evidence from four p0pulation surveys. Preventive Medicine. 17, 35-47.

Steptoe, A., & Cox, S. (1988). Acute effects of aerobic exercise on mood. Health
Peycholegy, 7, 329-340.

107

Steptoe, A., Edwards, 8, Moses, J., & Mathews, A., (1989). The effects of
exercise training on mood and perceived coping ability in anxious adults from the general
population. Journel of Psychosometic Research. 33. 537-547.

Steptoe, A., Kearsley, N., & Walters, N. (1993). Acute mood responses to
maximal and submaximal exercise in active and inactive men. Psychology and Health, 8,
89-99.

Tang, S. W., Stancer, H. C., Takahashi, S., Shephard, R. J., & Warsh, J. J. (1981).
Controlled exercise elevates plasma but not urinary MHPG and VMA. Psychiatry
Research 4, 13-20.

 

Tate, A. K., & Petruzzello, S. J. (1995). Varying intensity of acute exercise:
Implications for changes in affect. Jougel of Sports Medicine Ed Physical Fitnese, 35,
295-302.

Thayer, R. E., Peters, D. P., Takahashi, P. J., & Birkhead-Flight, A. M. (1993).
Mood and behavior (smoking and sugar snacking) following moderate exercise: A partial
test of self-regulation theory. Personelity end Individuel Differences. 14. 97-104.

Veale, D., LeFevre, K., Pantelis, C., deSouza, V., Mann, A., & Sargent, A.
(1992). Aerobic exercise in the adjunctive treatment of depression: A randomized
controlled trial. bumel of the Royel Society of Medicine. 85. 541-544.

Wilson, V. E., Morley, N. C., & Bird, E. I. (1980). Mood proﬁles of marathon
runners, joggers, and non-exercisers. Perceptual end Motor Skills. 50. 117-118.

Yeung, R. R. (1996). The acute effects of exercise on mood state. Journal of
Psychosometic Reseerch. 40. 123-141.

Zeiss, L. P., Lewinsohn, P. M., & Munoz, R. (1979). Nonspeciﬁc improvement
effects in depression using interpersonal skills training, pleasant activities schedules or

cognitive training. Journel of Consultirgend Clinical Psychology, 47, 427-439.

Zerihun, M. (2001). Depression drains workplace productivity. Retrieved
October 31. 2001. from http://wwwdepressionnet.org

108