Role of exercise training in secondary prevention of ischemic heart disease.

A review of recent studies indicates that: (1) Physiological characteristics, e.g., left ventricular performance and exercise tolerance, are important prognostic determinants; (2) the natural history of acute myocardial infarction includes a significant degree of spontaneous functional improvement during the early recovery phase; (3) short-term programs of physical training are likely to produce significant functional and symptomatic improvement at no cost in terms of excess mortality or morbidity--the mechanisms of improvement are largely peripheral and regulatory; (4) recent scintigraphic studies suggest that prolonged physical training produces improvement in left ventricular function and myocardial perfusion; (5) long-term studies of the effect of physical training on mortality and morbidity have failed to demonstrate conclusively the efficacy of exercise as a single agent, but provide support for the continued use of physical training as a component of multiple interventions.