Variability in the response to“post‐coronary”; exercise rehabilitation has previously been attributed to the age of the patient, their date of entry to the program relative to the acute incident, and the liability of the participant to anginal pain. We examined the relative importance of these three variables in a sample of thirty‐five patients seen two to 12 months after a well‐defined myocardial infarction. Cardiovascular responses of the patients at entry to the program and after six months and one year of intensive endurance training were evaluated by a progressive submaximal cycle ergometer test. Cardiac output was determined by a carbon dioxide rebreathing method. Training responses of the eight subgroups of patients was remarkably uniform; over the 12 months of observation, all showed an increase of stroke volume and a decrease of heart rate during submaximal work. The corresponding increase of predicted maximal oxygen intake ranged from 13 to 21%. We conclude that the variable cardiac response to training cannot be attributed to the factors that we examined. Other influences, such as cardiovascular status before infarction and the length of the training program may be involved.