Blood lactate accumulation decreases during the slow component of oxygen uptake without a decrease in muscular efficiency

作者：O'Connell J M; Weir J M; MacIntosh B R^*

来源：Pflugers Archiv-European Journal of Physiology, 2017, 469(10): 1257-1265.

DOI：10.1007/s00424-017-1986-y

• Oxygen uptake kinetics
• Exercise metabolism
• Anaerobic energy
• Heavy exercise
• Severe exercise

Pulmonary oxygen uptake () slowly increases during exercise above the anaerobic threshold, and this increase is called the slow component of . The mechanism of the increase in is assumed to be due to increasing energy cost associated with increasingly inefficient muscle contraction. We hypothesized that the increase in would be accompanied by a constant or increasing rate of accumulation of blood lactate, indicating sustained anaerobic metabolism while increased. Ten male subjects performed cycle ergometry for 3, 6, and 9 min at a power output representing 60% of the difference between lactate threshold and maximal while and blood lactate accumulation were measured. Blood lactate accumulation decreased over time, providing the energy equivalent of (mean +/- SD) 1586 +/- 265, 855 +/- 287, and 431 +/- 392 ml of during 0-3, 3-6, and 6-9 min of exercise, respectively. As duration progressed, supplied 86.3 +/- 2.0, 93.6 +/- 1.9, and 96.8 +/- 2.9% of total energy from 0 to 3, 3 to 6, and 6 to 9 min, respectively, while anaerobic contribution decreased. There was no change in total energy cost after 3 min, except that required by ventilatory muscles for the progressive increase in ventilation. The slow component of is accompanied by decreasing anaerobic energy contribution beyond 3 min during heavy exercise.

• 出版日期2017-10