The effect of exercise on clinical depression and depression resulting from mental illness: A meta-analysis

The effect of exercise on negative affect has been examined in hundreds of studies. However, the effect of exercise on diagnosed clinical depression h as received far less attention. Furthermore, poor methodological techniques predominate and results have been conflicting. A meta-analysis was conduct ed to investigate the effect of exercise on clinical depression and depress ion resulting from mental illness. The chosen studies examined the effect o f a chronic exercise paradigm (independent variable) on depression (depende nt variable). Each study's variables were coded: design, subjects, exercise , and dependent measure characteristics that could moderate the effect of e xercise on depression. Moderator variables were analyzed using analysis of variance (ANOVA). Results from 30 studies showed an overall mean effect of -.72. Therefore, individuals who exercised were -.72 of a standard deviatio n less depressed than individuals who did not exercise. Moderating variable s and implications for the prescription of exercise as an effective treatme nt fbr depression are discussed.