Exercise and Depression

1. Exercise and Depression

2. Exercise Against Depression Artal and Sherman The Physician and Sportsmedicine 26(10), 1998.

3. A Vital Primary Care Role Depression is the most common mental disorder. Research has consistently shown that 6% to 8% of all outpatients in primary care settings suffer from major depression. More than 7 million primary care visits were made annually in the early 1990s for the treatment of depression.

4. The Exercise-Depression Link Methodologic problems. Many studies refer to depression as a homogeneous entity rather than a spectrum of disorders.

5. The Exercise-Depression Link Despite methodologic problems, most studies have found exercise to have psychological and physiologic benefits for participants, with 90% of studies reporting antidepressant and anxiolytic effects. Taken as a whole, the research strongly suggests that benefits are greatest in individuals who have greater psychological impairment and in those who are clinically depressed, but both clinical and nonclinical populations benefit.

6. Clinical Populations Exercise is effective There is no evidence that any one kind of exercise has a greater impact on depression than others. A positive outcome did not depend on achieving physical fitness.

7. Non-clinical Populations Exercise benefits have also been seen in people who are not clinically depressed but are at high risk for depression or have some depressive symptoms. Roth DL, Holmes DS: Influence of aerobic exercise training and relaxation training on physical and psychological health following stressful life events. Psychosom Med 1987;49(4):355-365 55 college students who had had a high number of stressful life events in the previous year. The students were assigned to aerobic exercise training, relaxation training, or no treatment After an 11-week program, the exercisers scored lower on a standard depression inventory than the other two groups.

8. Why Does Exercise Help? Psychologically: Exercise may enhance one’s sense of mastery, which is important for both healthy and depressed individuals who feel a loss of control over their lives. Exercise may provide a therapeutic distraction that diverts a patient’s attention from areas of worry, concern, and guilt. Improving one’s health, physique, flexibility, and weight may all enhance mood. The ability to eat more freely without worries about gaining weight also increases pleasure, satisfaction, and a sense of self-control. Large-muscle activity may help discharge feelings of pent-up frustration, anger, and hostility.

9. Why Does Exercise Help? Physiologically/Neurochemistry Metabolism and turnover of monoamines and other central neurotransmitters at pre-synaptic and postsynaptic sites and their role in the mediation of depression.

10. Why Does Exercise Help?

11. Why Does Exercise Help? Depression: ? Serotonin (5-HT) Exercise increases serotonin levels

12. Why Does Exercise Help? Tryptophan (trip't?fan) , organic compound, one of the 20 amino acids commonly found in animal proteins. Only the L-stereoisomer appears in mammalian protein. It is one of several essential amino acids needed in the diet; human beings cannot synthesize it from simpler metabolites. Young adults require about 7 mg of this amino acid per day per kg (3 mg per lb) of body weight. Nicotinic acid (niacin), a vitamin of the B complex, can be made from tryptophan in the body, but evidently the rate of transformation is insufficient for the demands of normal growth and maintenance, and hence nicotinic acid must be supplied in the diet. Deficiency of tryptophan in the diet enhances the progress of the vitamin-deficiency disease pellagra, which is treated by restoring nicotinic acid to the diet, usually supplemented with tryptophan. Bacteria in the intestine break tryptophan down to compounds such as skatole and indole, which to a great extent are responsible for the unpleasant odor of feces. Tryptophan contributes to the structure of proteins into which it has been incorporated by the tendency of its side chain to participate in hydrophobic interactions (see isoleucine). The amino acid was isolated from casein (milk protein) in 1901, and its structure was established in 1907.

13. Why Does Exercise Help? Depression: ? Epinephrine?

14. Why Does Exercise Help? Tyrosine (ti'r?sen) , organic compound, one of the 20 amino acids commonly found in animal proteins. Only the L-stereoisomer appears in mammalian protein. It is not essential to the human diet, since it can be synthesized in the body from phenylalanine. When the enzyme that catalyzes the transformation of phenylalanine to tyrosine is not active because of a hereditary defect, the serious disease known as phenylketonuria (PKU) results. Other defects in tyrosine metabolism include the rare hereditary disorder known as alkaptonuria, characterized by discharge of a urine which darkens on standing exposed to air. Tyrosine is a precursor of the adrenal hormones epinephrine and norepinephrine as well as of the thyroid hormones, including thyroxine. Melanin, the skin and hair pigment, is also derived from this amino acid. Tyrosine residues in enzymes have frequently been shown to be associated with active sites. Modification of these residues with various chemicals often results in a change in the specificity of the enzyme toward its substrates or even in total destruction of its activity. In 1846 tyrosine was obtained as a product of the degradation of the protein casein (from cheese). It was synthesized in the laboratory in 1883, and its structure was thus determined.

15. Why Does Exercise Help? Depression: ? Beta-endorphins The ability of exercise to produce enough beta-endorphins to affect depression remains questionable. Several authors report elevated levels of beta-endorphins after acute exercise; however, the elevations in fit individuals are lower than in those who are not fit. Mood and CRH were elevated after running and meditation, but beta-endorphin was elevated only in the runners .

17. Why Does Exercise Help? Sleep 10-week program of weight training exercise (three times per week) significantly improved all subjective sleep quality and depression measures.

18. The Exercise Prescription Anticipate barriers Keep expectations realistic Introduce a feasible plan Accentuate pleasurable aspects Group activities should be encouraged State specifics Encourage compliance

19. Integrating Exercise With Other Treatments Antidepressants (e.g., fluoxetine hydrochloride, sertraline hydrochloride, paroxetine hydrochloride, nefazodone hydrochloride, and venlafaxine hydrochloride) appear to be compatible with exercise. An exercise prescription makes a useful contribution to psychotherapy.

20. Maintain Vigilance Though exercise has few if any adverse effects, some patients may misuse exercise. Those who have anorexia nervosa may undertake extreme physical activity, driven by a disturbed body image. Individuals who are compulsive in other areas of their lives may become compulsive about exercise at the expense of personal relationships and increased injury risk. These dangers may be obviated somewhat by stressing that exercise, like a prescribed drug, should be “taken as directed” and that more is not necessarily better. If dysfunctional attitudes are significant, they can be addressed in psychotherapy.

21. The Influence of Exercise on Mental Health Daniel Landers

22. Introduction Surgeon General’s Report on Physical Activity and Health (PCPFS Research Digest, 1996) “physical activity appears to relieve symptoms of depression and anxiety and improve mood” “regular physical activity may reduce the risk of developing depression, although further research is needed on this topic.”

23. Depression Clinical depression affects 2–5% of Americans each year (Kessler et al., 1994) Patients suffering from clinical depression make up 6–8% of general medical practices (Katon & Schulberg, 1992). Depressed individuals annually spend 1.5 times more on health care than nondepressed individuals

24. Depression During the 1990s there have been at least five meta-analytic reviews (Craft, 1997; Calfas & Taylor, 1994; Kugler et al., 1994; McDonald & Hodgdon, 1991; North, McCullagh, & Tran, 1990) Across these five meta-analytic reviews, the results consistently show that both acute and chronic exercise are related to a significant reduction in depression.

25. Depression These effects are generally “moderate” in magnitude (i.e., larger than the anxiety-reducing effects noted earlier) and occur for subjects who were classified as nondepressed, clinically depressed, or mentally ill. The findings indicate that the antidepressant effect of exercise begins as early as the first session of exercise and persists beyond the end of the exercise program (Craft, 1997; North et al., 1990). These effects are also consistent across age, gender, exercise group size, and type of depression inventory.

26. Depression Exercise was shown to produce larger antidepressant effects when: (a) the exercise training program was longer than nine weeks and involved more sessions (Craft, 1997; North et al., 1990); (b) exercise was of longer duration, higher intensity, and performed a greater number of days per week (Craft, 1997);

27. Depression The meta-analyses are inconsistent when comparing exercise to the more traditional treatments for depression, such as psychotherapy and behavioral interventions (e.g., relaxation, meditation), and this may be related to the types of subjects employed. That exercise is at least as effective as more traditional therapies is encouraging, especially considering the time and cost involved with treatments like psychotherapy. Exercise may be a positive adjunct for the treatment of depression since exercise provides additional health benefits (e.g., increase in muscle tone and decreased incidence of heart disease and obesity) that behavioral interventions do not.

28. Mechanisms Between Exercise and Reduced Depression Increase in norepinephrine Increase in serotonin However, increases in NE and 5-HT take longer than expected to reduce depression

29. Mechanisms Between Exercise and Reduced Depression HPA axis

31. Mechanisms Between Exercise and Reduced Depression Cortisol release (i.e. surges) is greatest in the morning and decreases over time. Depression shows higher levels of cortisol later in the day. The elevated cortisol may be due to excess levels of ACTH.

32. Summary The most common physiological explanations involve the action of monoamines and endorphins within the central nervous system The elevation of the body and brain temperature The distraction hypothesis (that "time out" from worry can trigger relief from depression) The mastery hypothesis (that the completion of an important task brings a sense of well-being).

33. Anxiety It is estimated that in the United States approximately 7.3% of the adult population has an anxiety disorder that necessitates some form of treatment.

34. Anxiety Anxiety is associated with the emergence of a negative form of cognitive appraisal typified by worry, self-doubt, and apprehension. Trait anxiety is the general predisposition to respond across many situations with high levels of anxiety. State anxiety, on the other hand, is much more specific and refers to the person’s anxiety at a particular moment.

35. Anxiety There have been six meta-analyses examining the relationship between exercise and anxiety reduction. All six of these meta-analyses found that across all studies examined, exercise was significantly related to a reduction in anxiety. This reduction occurs for all types of subjects, regardless of the measures of anxiety being employed (i.e., state, trait or psychophysiological), the intensity or the duration of the exercise, the type of exercise paradigm (i.e., acute or chronic), and the scientific quality of the studies.

36. Anxiety The meta-analyses show that the larger effects of exercise on anxiety reduction are shown when: (a) the exercise is “aerobic” (e.g., running, swimming, cycling) as opposed to nonaerobic (e.g., handball, strength-flexibility training), (b) the length of the aerobic training program is at least 10 weeks and preferably greater than 15 weeks, and (c) subjects have initially lower levels of fitness or higher levels of anxiety.

37. Anxiety There is limited evidence which suggests that the anxiety reduction is not an artifact “due more to the cessation of a potentially threatening activity than to the exercise itself” (Petruzzello, 1995, p. 109), and the time course for postexercise anxiety reduction is somewhere between four to six hours before anxiety returns to pre-exercise levels. The finding that exercise can produce an anxiety reduction similar in magnitude to other commonly employed anxiety treatments is noteworthy since exercise can be considered at least as good as these techniques, but in addition, it has many other physical benefits.

38. OTHER VARIABLES ASSOCIATED WITH MENTAL HEALTH Positive mood Self-esteem Restful sleep