In developed countries with high standards of medical care, myocardial infarction and sudden cardiac death secondary to advanced atherosclerosis constitute the primary cause of death within the productive adult life span. Although intensive care and improved technology have lowered mortality, morbidity frequency has not changed. Yet studies show that morbidity duration can be shortened by physical training, patient-family education and vocational counselling, with higher proportions of patients returning to productive work or satisfying achievement. Many literature references, as well as a recent NHLI Task Force report, have indicated the need for controlled studies of early exercise programs. This controlled study of early cardiac rehabilitation is investigating: (1) whether deconditioning is decreased by appropriately selected, graded and supervised exercise conditioning of skeletal muscle, given as dynamic rhythmic-exercises using the Smodlaka interval principle, when introduced earlier in the acute phase of mycardial infarction; and (2) whether the rate of return to work over a 6 month period is improved by continuing exercises within the hospital and after, combined with post-hospital education and counselling. By three-way randomized design, consecutive myocardial infarction patients including those who are entirely uncomplicated and those who stabilize following transient complications, are being studied as control and experimental groups during hospitalization and for six months after infarction. Data collection, over a one-year period, will include: heart rate, blood pressure, and electrocardiographic responses during in-hospital activity tests and maximal exercise tolerance tests at three and six months after infarction; psychosocial and risk factors, and data relative to medical-economic status will be assessed as they relate to theeffect of experimental programs. To strengthen statistical validity by increasing the number of subjects, this one-year grant renewal proposal would extend the work of the original plan by: (1) continuing data collection for one more year, (2) adding one more data collection site, and (3) includng in addition to uncomplicated patients, those who have had transient complications but have become stable, so that the experimental results will be more applicable to existing patient populations.