Evidence regarding health benefits of physical activity is overwhelming and plays a critical role in both the primary and secondary prevention of coronary artery disease (CAD). Epidemiological investigations show approximately half the incidence of CAD in active compared to sedentary persons. A sedentary lifestyle is considered by various national and international organizations to be one of the most important modifiable risk factors for cardiovascular morbidity and mortality. Fortunately, a moderate level of occupational or recreational activity appears to confer a significant protective effect. Once coronary artery disease has become manifest, exercise training can clearly improve the functional capacity of patients and reduce overall mortality by decreasing the risk of sudden death. Well-designed clinical investigations, supported by basic animal studies, have demonstrated that the beneficial effects of exercise are related to direct and indirect protective mechanisms. These benefits may result from an improvement in cardiovascular risk factors, enhanced fibrinolysis, improved endothelial function, decreased sympathetic tone, and other as-yet-undetermined factors. Hence physical fitness, more than the absence of ponderosity or other factors, is the major determinant of cardiovascular and metabolic risk and long-term disease-free survival, in effect linking health span to life span. It is obviously in every individual's interest to assume the responsibility for his or her own health and embrace this extremely effective, safe, and inexpensive treatment modality. The need for a comprehensive review of this particular topic has arisen in view of the high prevalence of physical inactivity and overwhelming evidence regarding CVD risk reduction with regular physical activity.