EXERCISE AND ITS ROLE IN THE PREVENTION AND REHABILITATION OF CARDIOVASCULAR-DISEASE

The purpose of this article is to review the beneficial effects of reg ular exercise in the primary and secondary prevention of coronary arte ry disease (CAD). Epidemiologic studies indicate that a physically ina ctive life-style is associated with twice the risk of developing CAD. The magnitude of risk is similar to that of other modifiable risk fact ors. Meta-analysis of studies of cardiac rehabilitation after myocardi al infarction demonstrate that cardiac rehabilitation participants low er their risk of death by 20% to 25% compared to controls. Exercise tr aining results in several beneficial physiological changes including a n increase in exercise endurance, higher resting and exercise stroke v olumes, lower resting and submaximal exercise heart rates, and increas ed 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 othe r risk factors, but the benefits are modest, Reductions in systolic an d 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 ill high-density lipoprotein (HDL) cholesterol approximate 2 mg/dL. Exercise training as a sole intervention does no t appear to enhance smoking cessation. Regular exercise does improve p sychosocial well-being. Most studies of physical activity have enrolle d predominantly middle-aged men: however; available evidence suggests similar cardiovascular benefits for women, the elderly, and children a nd youth. Physical activity levels decrease substantially during the s chool-age-adolescent transition in both males and females, More than h alf of the adult population is sedentary or inactive. Collectively, ac cumulated data suggest the need for both individualized/high-risk and population-based approaches to increasing physical activity across the life span.