I want to convey that exercise is like taking a small Prozac or a small Ritalin at the right time,” says Dr. John J. Ratey, associate professor of psychiatry at Harvard Medical School and author of A. User Guidebrainhe Brain. “Movement is for the brain, not for the body. It affects mood, alertness, and well-being.” Stephen C. Putnam, MEd, took canoeing seriously to combat the symptoms of ADHD (Attention Deficit Hyperactivity Disorder) in adults. Then he wrote a book named Nature’s Ritalin for the Marathon Mind about the benefits of exercise for disturbing brain disorders. Such as ADHD, a neurological/behavioral disorder that leads to hyperactivity and an inability to focus on tasks.