This workshop examines exercise as a means of evaluation, prescription, and diagnosis of the major threat to health in the United States today: heart disease. Recent studies with their findings and implications will be reviewed. The scientific basis for recommended exercise and associated behavior will provide information with regard to children and adults of both sexes on reducing heart disease risk. Rehabilitative exercise programs for heart victims will focus on accepted training principles and the necessity for changing life styles. Prevention rather than treatment for heart disease will be stressed.