Effect of Pre-Existing High Blood Lactate Concentration on Maximal Exercise Performance

Abstract

Four male subjects exercised with the leg muscles (cycling) at ‘supermaximal’ intensities, which led to complete exhaustion within 3 to 6 min under two different conditions. In one condition the blood lactate concentration ([HLa]) was on the average 1.2 mmol at the onset of exercise (series I) and in the other it was 10.2mmol (series II). It was found that the maximal [HLa] in blood following exhaustive exercise was slightly higher in series II than in series I, while the increase in blood [HLa] during exercise was much smaller in series II. The maximal V˙O₂ was the same in series I and II, but there was a tendency for exercise time to be reduced in series II. The O₂-debt after exercise was greater in series II than in series I. It is concluded that the existence of high blood [HLa] prior to exhaustive exercise does not affect maximal oxygen uptake but can inhibit further lactate production in the exercising muscles. While a tendency toward reduced endurance capacity was observed in this condition, the hypothesis that lactate constitutes a limiting factor in exercise was not confirmed.

Key Words:

• Blood pH
• endurance
• heart rate
• maximal aerobic power
• oxygen uptake
• pulmonary ventilation