This review deals with more recent investigations of the health benefit of regular aerobic exercise including studies in: epidemiology, echocardiography, animal research, and cardiac rehabilitation. Recent epidemiological studies support the preventative aspects of exercise in apparently healthy individuals. Echocardiographic studies suggest morphologic changes in young individuals. Recent animal research confirms previous results as well as documenting improvment in cardiac function even under hypoxic and ischemic conditions. Studies of cardiac rehabilitation suggest that medically supervised programs do not improve or worsen morbidity and mortality. The question of whether exercise training can cause cardiac effects in patients with coronary disease rather than just improve the response of the peripheral circulation to exercise may be answered using newer radionuclide techniques.