Effect of training on maximum oxygen intake and on anaerobic metabolism in man

The concentration of lactate and pyruvate was determined in the blood of 13 subjects at three aerobic and four anaerobic levels of work before and after a period of training on a constant work-rate bicycle ergometer. In addition each man's maximum oxygen intake was established on either the bicycle ergometer or the motor-driven treadmill, by means of the Douglas bag technique, before and after the period of training. The results obtained demonstrated that a regime of training influenced the maximum oxygen intake and also the level of oxygen intake at which “excess lactate” starts to appear in the blood. During the training of the subjects these two physiological parameters changed independently of each other but large individual differences were also observed. The mean maximum oxygen intake of the men, which was 2.888l/min before training, increased to 3.060l/min (a change of 7 per cent) after the men had trained for a period of 4 to 16 weeks. During this period of training the mean level of oxygen intake, expressed as a percentage of the maximum value, at which “excess lactate” appeared increased from 46 to 62 per cent. The relationship between the degree of fitness and the appearance of anaerobic metabolism during work is discussed. In untrained individuals the onset of anaerobic metabolism occurred at 40–45 per cent of the maximum oxygen intake, in trained individuals at 55–60 per cent and in the exceptionally well-trained men at about 70 per cent.