In-hospital exercise after myocardial infarction does not improve treadmill performance.

Prolonged bed rest after myocardial infarction is thought to result in deconditioning, manifested by increased heart-rate and blood-pressure responses to exercise and decreased functional capacity. We studied the effects of early, supervised exercises in preventing deconditioning after acute myocardial infarction. Eighty-four patients were randomized to a control group and 174 to an exercise group. Enrollment in the exercise program occurred an average of 4.5 days after admission (range, one to nine). Discharge from the hospital occurred an average of 10.3 days after admission in the control group and 10.4 days in the exercise group. Most patients had a low-level treadmill test on the day before hospital discharge. There were no differences between the two groups in the clinical, hemodynamic, or electrocardiographic responses to the treadmill test. Incidences of complications and deaths (one death in each group) during hospitalization were not significantly different in the two groups, although six patients (3 per cent, all in the exercise group) required cardiac surgery--four because of recurrent chest pain and two because of rupture of heart muscle. Thus, we were unable to demonstrate any significant beneficial or deleterious effects of an early, in-hospital exercise program.