Exercise improves depression. In fact, some studies even show that exercise is more effective than prescription antidepressants in preventing depression relapses (see Psychosomatic Medicine [2000; 62, 633–38]). To date, however, scientists have been unable to identify the causal mechanisms that would clarify how exercise helps. Now, a study published in Neuropsychopharmacology (2006; 31, 256–64) has confirmed that exercise stimulates new brain cell growth, or neurogenesis. This could explain why working out makes us feel better.
Investigators from the Karolinksa Institute in Sweden studied depressed rats. (They were depressed according to the Flinders Sensitive Line and the Flinders Resistant Line, which are used to assess depression in animals.) Some rats were given access to running wheels, while others were not. Regular running resulted in an antidepressant effect and increased brain cell proliferation in the rats.
More research is required to confirm whether similar effects would occur in humans.