Exercise and its role in the prevention and rehabilitation of cardiovascular disease.

The purpose of this article is to review the beneficial effects of regular exercise in the primary and secondary prevention of coronary artery disease (CAD). Epidemiologic studies indicate that a physically inactive life-style is associated with twice the risk of developing CAD. The magnitude of risk is similar to that of other modifiable risk factors. Meta-analysis of studies of cardiac rehabilitation after myocardial infarction demonstrate that cardiac rehabilitation participants lower their risk of death by 20% to 25% compared to controls. Exercise training results in several beneficial physiological changes including an increase in exercise endurance, higher resting and exercise stroke volumes, lower resting and submaximal exercise heart rates, and increased capillary density and oxidative enzyme capacity in skeletal muscle. In patients with established CAD, exercise training improves symptoms of angina and congestive heart failure and attenuates the severity of exercise-induced ischemia. Regular exercise can favorably modify other risk factors, but the benefits are modest. Reductions in systolic and diastolic blood pressure readings average 6 to 9 mm Hg; decreases in total and low-density lipoprotein (LDL) cholesterol approximate 5 to 10 mg/dL; and increases in high-density lipoprotein (HDL) cholesterol approximate 2 mg/dL. Exercise training as a sole intervention does not appear to enhance smoking cessation. Regular exercise does improve psychosocial well-being. Most studies of physical activity have enrolled predominantly middle-aged men; however, available evidence suggests similar cardiovascular benefits for women, the elderly, and children and youth. Physical activity levels decrease substantially during the school-age-adolescent transition in both males and females. More than half of the adult population is sedentary or inactive. Collectively, accumulated data suggest the need for both individualized/high-risk and population-based approaches to increasing physical activity across the life span.