A study at Duke University found that a 16-week exercise program worked as well as antidepressant drugs on adults with symptoms of major depression. The study included 202 men and women divided into four groups: one group took antidepressants; a second group took a supervised exercise class three times a week; a third group worked out at home. The fourth group took a placebo.

At the end of the study, 47% of the patients on the antidepressants and 45% of those in the exercise class were no longer depressed. The group that exercised at home did well, too: 40% had overcome their symptoms. Of those who took the placebo, only 31% improved. Exercise may have the same beneficial effect on the brain chemicals involved in depression as the drugs that target these substances. The study was published in Psychosomatic Medicine (September 2007).