A vast amount of literature exists on the improvements in work capacity, reduction of risk factors, and an increased feeling of well-being among coronary heart disease patients after physical training programs. Previous observations of short-term training programs which resulted in an increase in physical working capacity have not usually shown a cardiac change. The National Exercise and Heart Disease Project did not show such changes, but the exercise level may have been inadequate. Several other studies suggested that more prolonged and intense training could result in improved cardiac function.