Adaptation to exercise in angina pectoris.

PATIENTS with angina pectoris due to coronary artery disease may have great variability in exercise tolerance. In some this variability fits a pattern wherein increased exercise tolerance is dependent on a preceding episode of exercise-induced angina pectoris. The most complete expression of this phenomenon may be in the patient who is able to overcome an attack of angina pectoris by persisting in the precipitating effort until the pain disappears, with subsequent continuation of exercise without distress. An unknown patient described just such an occurrence in a letter to William Heberden. "I have frequently, when in company, borne the pain, and continued my pace without indulging it; at which times it has lasted from five to perhaps ten minutes, and then gone off."' This has been compared to the occurrence of a "'second wind" in athletes and described as "<walking through one's angina." A less impressive, but more common manifestation of the same phenomenon occurs when a patient, after being brought to a halt one or more times by his angina pectoris, is subsequently able to resume the same effort and continue it indefinitely without discomfort. This often occurs in the morning with the first exertion of the day, subsequent activity being carried on without discomfort. It has been likened to the improved performance of an athlete after he is thoroughly warmed up. This has been termed "angina of first effort," and has been called "first hole angina pec-