April 9, 2007 issue - A sound mind in a sound body is a short, but full description of a happy state in this world," wrote the British philosopher John Locke. Three hundred years later, research shows that we should begin thinking of body and mind health as conceptually identical. The two are linked at the deepest levels.

　　For several decades we've known about one effect of exercise on the brain, the "endorphin high" that makes us feel good during and right after exercise. Recently, scientists have uncovered some longer-lasting effects of exercise on the brain. Regular exercise improves your mood, decreases anxiety, improves sleep, improves resilience in the face of stress and raises self-esteem.