Exercise for depression.

Depression is a common and important cause of morbidity and mortality worldwide. Depression is commonly treated with antidepressants and/or psychological therapy, but some people may prefer alternative approaches pharmacological treatment and found no significant difference (SMD -0.11, -0-0.32 to 0.26). Four trials (n = 300) compared exercise with .34, 0.12). One trial (n = 18) reported that exercise was more effective than bright light therapy (MD -6.40, 95% CI -10.20 to -2.60).For each trial that was included, two authors independently assessed for sources of bias in accordance with the Cochrane Collaboration 'Risk of bias' tool. In exercise trials, there are inherent difficulties in blinding both those receiving the intervention and those delivering the intervention. Many trials used participant self-report rating scales as a method for post-intervention analysis, which also has the potential to bias findings. Exercise is moderately more effective than a control intervention for reducing symptoms of depression, but analysis of methodologically robust trials only shows a smaller effect in favour of exercise. When compared to psychological or pharmacological therapies, exercise appears to be no more effective, though this conclusion is based on a few small trials.