title: Effects of the limiting symptom on the achievement of maximal oxygen consumption in patients with coronary artery disease.
abstract: This study was conducted to determine if the limiting symptom in patients with coronary artery disease (CAD) influenced the pattern of oxygen consumption (VO2) over the final 90 seconds of a maximal exercise test. The pattern was classified according to the presence or absence of a plateau. Twenty-six normal persons and 55 patients with CAD were studied. They rated the severity of fatigue, dyspnea and angina at end exercise using the Borg scale and designated which symptom was the limiting factor. A plateau of VO2 over the final 90 seconds of exercise was observed in 77% of normal subjects and patients with CAD. Eighty percent of patients limited by angina achieved a plateau. In normal subjects and patients with CAD, peak VO2 was more reproducible than the pattern of VO2 over the final 90 seconds of exercise. There were no differences in the cardiac responses to exercise at maximal effort between patients who achieved a plateau of VO2 and those who did not. These results indicate that the limiting symptom of exercise, even angina pectoris, does not influence the ability to exercise maximally. Therefore, the peak value of VO2 during symptom-limited treadmill exercise is a valid measure of maximal cardiovascular capacity irrespective of the limiting symptom or the pattern of VO2 in the final 90 seconds of exercise.
mesh_terms: D000328:Adult; D000787:Angina Pectoris / Q000150:complications; D003327:Coronary Disease / Q000503:physiopathology*; D004417:Dyspnea / Q000150:complications; D005080:Exercise Test; D005221:Fatigue / Q000150:complications; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption