Research data in adults have provided convincing evidence that regular exercise creates a protective effect against the complications of coronary artery disease. Given that the atherosclerotic process begins during the pediatric years, improved physical activity and fitness has been promoted in children and adolescents as a means of preventing cardiovascular disease in adulthood. Although intuitively compelling, direct proof of this rationale for improving exercise habits of children is not available. Scientific data examining the effects of activity and fitness on coronary artery disease risk factors in the growing years do provide some evidence that promoting exercise in children might serve as a means of preventing future cardiovascular disease.