A controlled prospective study of the effect of endurance training on the recurrence rate of myocardial infarction. The Ontario exercise heart collaborative trial. An interim report

The Ontario Exercise-Heart Collaborative Trial was initiated in 1972. It is a multicentre prospective study designed to determine whether participation in an exercise program, which produces a significant training effect, will affect the recurrence rate in men who have survived an initial myocardial infarction. The subjects were volunteers who entered the trial if they met the following criteria: under 54 years of age, non-diabetic, or diabetic controlled on diet alone, free of any orthopaedic disability which would prevent full participation, absence of cardiac failure, an interval of not more than 1 year since infarction, an absence of significant airway obstruction (FEV1/VC of not less than 60%). The subjects were allocated to the experimental and control groups in a stratified random fashion according to the following prognostic risk factors: angina, hypertension, blue collar or white collar and type A or type B personality. The experimental group met twice weekly for a program based predominantly on endurance training. The control group met twice weekly for a program of recreational activities and relaxation sessions designed to produce a minimal training effect. To date, 753 subjects have entered the study, 387 in the experimental group and 366 in the control group. There have been 22 non-fatal re-infarctions in the experimental group and 15 non-fatal re-infarctions in the control group. The incidence of fatal recurrent infarction was 6 in the experimental group and 6 in the control group. The drop-out rate is 38% in the experimental group and 38% in the control group.