Exercise for the Mind

VIewing 14 studies in which supervised exercise programs were used to treat clinical depression, researchers found that patients with mild to moderate depression who walked, ran or performed strength training three times a week for 20 to 60 minutes were significantly less depressed after as few as five weeks.

Studies that tracked subjects for up to one year found that when workouts were kept up, the improvements continued. How physical activity keeps the mind fit isn't clear, but researchers speculate it may alter brain chemistry.