Abstract
To the Editor: The article by Redwood et al. (N Engl J Med 286:959–965, 1972) adds to the growing body of evidence that physical training can be effective treatment for patients with angina pectoris by decreasing heart rate and blood pressure and thus myocardial oxygen requirements at a given level of exertion. However, the unique feature of their report — the suggestion that training might improve myocardial oxygen delivery — is open to question. Their argument depends upon the product of heart rate, systolic pressure, and ejection time being a good approximate index of myocardial oxygen consumption (MV̇o2) . . .