The benefits and risks of exercise training: the exercise prescription.

The physiologic responses to exercise are mediated by a complex interaction of central, peripheral, and neurohumoral stimuli designed to increase cardiopulmonary function. With repetitive exercise, significant cardiovascular and muscular adaptations occur that facilitate and enhance the response to exercise. Exercise is beneficial not only to younger healthy individuals, but to patients with many chronic medical conditions and to elderly individuals as well. Physical activity has a role in the reduction of major cardiac risk factors and in both the primary and secondary prevention of cardiac events. With proper evaluation and counseling, exercise can be performed safely, even among patients with cardiovascular and other chronic diseases. Given the high percentage of the U.S. population whose sedentary lifestyle predisposes them to the development of cardiovascular disease and the numerous beneficial effects of exercise, it is prudent to prescribe exercise as a means of improving individual and general public health.