SOME PROPERTIES OF MAXIMAL AND SUBMAXIMAL EXERCISE WITH REFERENCE TO PHYSIOLOGICAL VARIATION AND THE MEASUREMENT OF EXERCISE TOLERANCE

Abstract

Thirty-one normal young <[male][male] were given an exercise test twice, consisting of a 4 min. walk on the treadmill (submaximal), and a run to exhaustion (maximal), the retest following in three days. Heart and respiration rates, ventilation, blood lactate, percents oxygen and CO2, and oxygen consumption were detd. during both walk and run. A performance criterion, time-run to exhaustion, was more reliable than any of the physiological measures, but was closely approached by a battery of heart rate measures including the second derivative of a cubic fit to the heart rate curve obtained during the run. This battery correlates 0.90 with the criterion and the stability of the relation is proved by cross-application of the regression coefficients. No combination of submaximal and/or maximal physiological measures, if some measure of trend of adaptation during work was omitted, yielded an acceptable correlation with the criterion or performance. The validities of such indices as O2 pulse, ventilation efficiency, and pulse recovery are seriously questioned. The high correlation between the time-run criterion and the heart rate battery, which serves as a reliable index of adaptation to maximal exercise, offers promise for the development of a practical and valid test of exercise tolerance.