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Exercise Helps Severe Depression: But are the Studies Conclusive?

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Updated November 13, 2008

Medical studies often show that exercise is helpful for those with depression and anxiety, even those with severe depression. But the "Harvard Mental Health Letter" December 2005, points out biases and flaws common to these studies that could influence the results. Exercise is good for health no matter how it may affect mood disorders and should be encouraged for all people.

How Exercise May Help Depression and Anxiety

  • Exercise produces endorphins, the body's own mood enhancers, and alters the circulation of neurotransmitters much as anti-depressant drugs do.
  • Distracts from everyday stresses - may act as a predictable stress to immunize you against other stresses.
  • Provides a social support system when exercising with others, connection with the community.
  • Improves your body image, reconnects you with your body.
  • Allows setting and achieving of goals, building self-confidence.
  • Maintains health - one less thing to be depressed or anxious about.

Exercise and Depression: The Chicken or the Egg?

Some studies show that being sedentary seems to track along with being prone to depression or anxiety. But it could be that being depressed makes you less inclined to exercise. Or is it that being sedentary makes you depressed? Or is some third factor making people both sedentary and depressed? It is hard to make conclusions from the bulk of the research.

Controlled Studies Hard to Control

Biases can sneak into behavioral studies despite the best attention to study design. The participants volunteering for an exercise study may not be typical of sedentary people with depression or anxiety. They must have some inclination to exercise or they would not volunteer. Those who make it through the study period adhering to the exercise protocol are also less likely to be typical.

Researcher expectations can also bias a study. If the researcher expects that exercise improves mood, he or she can unconsciously and subtlely influence the results. The study can't be double-blind like taking a sugar pill vs. a study drug - the participants all know whether they are in the exercise group or the non-exercise control group. Those who exercise probably expect to feel better, and they are more likely to report that they felt better, if only to please the researcher. At best, the study can be single-blind where the researcher follows up with tests such as questionnaires and scoring them without knowing which group the participant was in.

Studies may not follow the participants for a long enough time frame to see whether they continued to exercise and continued to have a better outcome.

Results are in, Exercise is Good for You Anyway

The health effects of exercise in preventing disease and improving the quality of life are well-proven. Those with depression or anxiety should be encouraged to be active, doing whatever exercise or activity they most enjoy. But there's the problem - depressed people don't enjoy anything, that's a definition of depression. But they can be encouraged to stay active. The Harvard Mental Health Letter suggests walking, gardening, and household chores as activities for those who dread other exercise activities.

Source: Press Release, Harvard Mental Health Letter, December, 2005
Last Updated: 11/22/05

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