Exercise and Depression
Exercise and Depression
May 2000; Volume 2; 33-36
By Carmen Tamayo, MD
Can a prescription for exercise be used to treat depression? The role of physical exercise in improving mental well-being has been studied for more than 20 years. Research in this area has increased considerably over the years, although many studies are plagued with methodological shortcomings including small sample size, lack of randomization, lack of a no-treatment group, short study duration, and failure to take into account the natural history of depression. Nevertheless, substantial evidence indicates that exercise is associated with improvements in mental health.
Epidemiology of Depression
Depression is more common in women than in men. Recent epidemiological surveys in general populations of different countries worldwide found lifetime prevalence rates of major depression between 3.3% and 17%.1 Lifetime annual episode rates in women worldwide are around 7%.2 Up to 15-20% of older adults have significant depressive symptoms.3 In the United States, depression is a common disorder with an estimated lifetime prevalence of 17%; as many as 35% of individuals with major depressive disorder have a chronic course.4
Although biochemical explanations are most widely accepted, conflicting social roles and expectations, continued violence against women and children, and the extreme differences in socio-economic opportunities and conditions between men and women are also cited as reasons for women’s higher rates of depression in the United States.5
Exercise and Depression
Several surveys note lower rates of depression among exercisers; for example, a survey of 401 people ages 18-83 found a positive correlation between exercise and psychological well-being in the general population (the greater the level of physical activity, the higher the level of psychological well-being).6 Another survey of 97 regular exercisers (> 5 hours weekly) and 259 non-regular exercisers that examined the effects of regular, moderate exercise on mood states and menstrual cycle symptoms found that exercise was correlated with less negative mood states and lower scores on a menstrual distress questionnaire.7
Another observational study of 4,032 employees from companies participating in a wellness program reported that employees with good physical fitness exhibited the lowest prevalence of psychological distress, followed by those with average level of fitness. The unfit showed the highest prevalence of distress.8
The question of whether exercise lowers depression rates or depression lowers exercise rates, however, cannot be answered in observational studies.
Clinical Trials on Depression and Exercise
Controlled studies, however, indicate that exercise may be a viable adjunct to (or even in some cases a replacement for) antidepressant medication. A recent study of 56 older patients suggests that exercise can treat major depression as effectively as antidepressants (although antidepressants were associated with a more rapid therapeutic response).9 Patients were randomly assigned to aerobic exercise, antidepressants, or both. After 16 weeks of treatment, exercise was equally effective as medication. Patients in this study were healthy, motivated, and tended to be highly educated, so it is unclear whether results are generalizable to other depressed individuals. In addition, no studies comparing the combination of exercise and antidepressant medication against either on its own are available.10
Several other studies have compared exercise with psychotherapy for depressed individuals and concluded that both were equally efficacious.11 Some studies suggest that the addition of exercise to counseling is more effective in the treatment of depressive disorders than counseling alone, but others conclude that the combination is no more effective than either alone.
A study of 49 depressed volunteers examined separate and combined effects of aerobic exercise and counseling.12 Although aerobic exercise and counseling were equally effective in improving depression, the combination was no more beneficial than either treatment alone.
Two clinical trials have been conducted in a sample of depressed patients (n = 124, mean age 35.5 years) to determine the adjunctive effect of adding an aerobic exercise program (three supervised sessions per week) to usual treatment with psychotherapy or psychotropic medication (57% of patients).13 In the first trial, after 12 weeks the aerobic exercise group had a superior outcome compared with a control group in terms of trait anxiety and a standard psychiatric interview. A second trial was then conducted to compare aerobic exercise with low-intensity exercise (relaxation, yoga, and stretching exercises) to determine the effect of aerobic fitness. Both groups showed improvement in depression and there were no significant differences between the groups.
Another trial provides more support for the finding that exercise does not have to be aerobic to have a beneficial effect. A randomized, controlled trial of 99 depressed inpatients compared aerobic with non-aerobic forms of exercise.14 Subjects were randomly assigned either to aerobic (brisk walking and jogging) or non-aerobic (strength training, flexibility, and relaxation) physical training; in both conditions, subjects exercised three times a week for a period of eight weeks. Depression scores in both groups were significantly reduced during the study, and the reduction was not limited to intensive aerobic forms of exercise.
An earlier, oft-quoted trial found running as effective as psychotherapy. This 10-week trial in mildly depressed patients (including 15 women) randomized 28 subjects aged 18-30 years to running or to 10 sessions of time-limited or time-unlimited individual psychotherapy.15 Ten patients received running treatment (running leader met with patients 3-4 times/week for 1 hour for the first five weeks; twice during the 5th week and once during the 7th and 8th week). Patients were encouraged to run at least three times per week either with the leader or on their own. There were two dropouts in the running group and four dropouts in the psychotherapy groups. Running treatment was as effective as both types of psychotherapy in alleviating depressive symptoms. The authors noted the possibility that the running coach was an "effective" psychotherapist, and that the group interaction among those assigned to running may have been more important than running itself. An additional criticism is that statistical tests were not reported.
Another randomized, controlled 12-week trial of 74 depressed people compared running (two 45-minute sessions weekly) to meditation-relaxation (two hours weekly) or group therapy (interpersonal and cognitive therapy).16 Measures of depression, general psychological distress, and symptom change were taken. All groups experienced significant decreases for the two measures relevant to depression; improvements were also seen in self-esteem, body image, and stress reduction. Benefits persisted at nine months.
One problem with the above trials is that they were all treatment-controlled, and depression often remits over time. The necessity of including a no-treatment group is emphasized by a randomized, controlled 10-week trial of 47 undergraduate women diagnosed with mild depression that compared aerobic exercise (n = 16) to relaxation training (n = 15) and no treatment (n = 16).17 Aerobic exercise training (one hour twice per week of strenuous dancing, jogging, and running) and exercise outside class were combined to achieve 30 "aerobic points" per week. Relaxation training consisted of progressive muscle relaxation for 15-20 min/d, four days per week. All groups, including the no-treatment group, showed reliable and substantial reductions in their depression that were independent of any specific treatment. Interestingly, subjects in this study were not aware that depression was being measured; the experiment was presented as a stress management study.
Exercise intensity and duration are also important components of using physical activity therapeutically. A recent study comparing continuous moderate (30 min/d) vs. intermittent moderate (three 10-minute sessions daily, each separated by two hours) physical activity noted that continuous intensity was more effective in improving mood symptoms than an intermittent regimen.18 Since many people with mental health disorders may dislike a vigorous exercise regimen, recommending a continuous moderate intensity program of 30 min/d, three days per week may produce greater adherence and success.11
Mood in Breast Cancer Survivors
Exercise has also been shown to improve depressive symptoms in breast cancer survivors. A 10-week study of 24 breast cancer survivors (mean age 48.9 years) randomized subjects into exercise (EX), exercise plus behavior modification (EX/BM), and control groups.19 EX and EX/BM groups exercised aerobically four days per week. Assessments were made at baseline, at study end, and 12 weeks later. Because there were no statistical differences between EX and EX/BM groups, these data were combined. Women who exercised had significantly less depression and anxiety (state and trait) over time compared to controls. Self-esteem did not change significantly. Subjects who received exercise recommendations from their physicians exercised significantly more than subjects who received no recommendation.
Conclusion
Depressed patients often are sedentary. Increased activity may have psychological as well as physical benefits and is a strong argument for integrating physical fitness training into comprehensive treatment programs for depression. Physical exercise may be useful and appears to be as effective as psychotherapy for the treatment of mild-to-moderate unipolar depression. Aerobic and anaerobic forms of exercise are equally effective in controlling depression, and no change in fitness level need occur for psychological benefits to accrue. An exercise training program should be considered as an alternative or adjunctive treatment for mild depression. Exercise programs may be more cost-effective than psychotherapy or drug treatments, but there is need for expert administration and monitoring of individualized programs and for cost-effectiveness comparisons in this area. More research is needed to determine the effect of exercise in specific populations such as people with disabilities, adolescents, and older adults because studies with these populations have been limited. Additional large well-controlled studies are needed to clarify the mental health benefits of exercise and to explain the underlying mechanisms.
Dr. Tamayo is Director, Division of Complementary and Alternative Medicine, Foresight Links Corp. in London, ON.
References
1. Wacker HR. [No title available.] Ther Umsch 2000;57:53-58.
2. Angst J. Epidemiology of depression. Psychopharmacology 1992;106:S71-S74.
3. Gallo JJ, Lebowitz BD. The epidemiology of common late-life mental disorders in the community: Themes for the new century. Psychiatr Serv 1999;50:1158-1166.
4. First MB, et al. Nosology of chronic mood disorders. Psychiatr Clin North Am 1996;19:29-39.
5. Brandis M. A feminist analysis of the theories of etiology of depression in women. Nurs Leadersh Forum 1998;3:18-23.
6. Ross CE, Hayes D. Exercise and psychologic well-being in the community. Am J Epidemiol 1988;127:762-771.
7. Aganoff JA, Boyle GJ. Aerobic exercise, mood states and menstrual cycle symptoms. J Psychosom Res 1994;38:183-192.
8. Tucker LA. Physical fitness and psychological distress. Int J Sport Psychol 1990;21:185-201.
9. Blumenthal JA, et al. Effects of exercise training on older patients with major depression. Arch Intern Med 1999;159:2349-2356.
10. Weyerer S, Kupfer B. Physical exercise and psychological health. Sports Med 1994;17:108-116.
11. Paluska SA, Schwenk TL. Physical activity and mental health: Current concepts. Sports Med 2000;29:167-180.
12. Freemont J, Craighead LW. Aerobic exercise and cognitive therapy in the treatment of dysphoric moods. Cogn Ther Res 1987;11:241-251.
13. Veale D, et al. Aerobic exercise in the adjunctive treatment of depression: A randomized controlled trial. J R Soc Med 1992;85:541-544.
14. Martinsen EW, et al. Comparing aerobic with nonaerobic forms of exercise in the treatment of clinical depression: A randomized trial. Compr Psychiatry 1989;30:324-331.
15. Greist JH, et al. Running as treatment for depression. Compr Psychiatry 1979;20:41-54.
16. Klein MH, et al. A comparative outcome study of group psychotherapy vs. exercise treatment for depression. Int J Ment Health 1985;13:148-177.
17. McCann IL, Holmes DS. Influence of aerobic exercise on depression. J Pers Soc Psychol 1984;46:1142-1147.
18. Osei-Tutu KEK, Campagna PD. Psychological benefits of continuous vs. intermittent moderate-intensity exercise [abstract]. Med Sci Sports Exerc 1998;30(Suppl5):S117.
19. Segar ML, et al. The effect of aerobic exercise on self-esteem and depressive and anxiety symptoms among breast cancer survivors. Oncol Nurs Forum 1998;25:107-113.
Funding of Reviewed Studies
Reference 1: Psychiatric University Hospital, Zurich. Reference 2: School of Medicine of the University of Pennsylvania. Reference 4: Institute for Social Research, University of Michigan. Reference 5: Columbia Presbyterian Medical Center, New York. Reference 6: University of Illinois, Urbana. Reference 9: National Institutes of Health, Pfizer Pharmaceuticals. Reference 10: The Central Institute of Mental Health, Mannheim, Germany. Reference 13: Health Promotion Research Trust, Bloomfield Charitable Trust. Reference 14: Central Hospital, Forde, Norway. References 15, 16: University of Wisconsin Medical School, University of Wisconsin, National Institute of Mental Health, and Wisconsin Psychiatric Research Institute. Reference 17: Supported in part by the University of Kansas. Reference 19: University of Michigan, Ann Arbor. References 3, 7, 8, 11, 12, 18: Not stated.
May 2000; Volume 2; 33-36
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