Physical Activity Is Associated with Lower Rates of Incident Depression

Many studies show a general association between greater physical activity and lower risk for depression. In this meta-analysis, researchers sought to quantify a dose–response relation by evaluating 15 observational studies (190,000 participants with follow-up ranging from 3 to 25 years) with a wide range of activity level measures that could be harmonized into a single measure of marginal metabolic equivalent task hours per week (mMET-h/wk). A mMET is any nonoccupational leisure-time or domestic physical activity that is incremental to basal daily or work activities. A 1-hour brisk walk would equal about 3.5 mMET-h. Depression was measured as either self-reported physician diagnosis or depression symptoms on a validated screening instrument…