Anaerobiosis, lactate, and gas exchange during exercise: the issues.

The lactate increase during exercise is a critically important biochemical and physiological event that leads to decreasing cell pH, an accelerated rate of glycogen depletion in the muscle, and important changes in ventilatory and gas exchange dynamics. Lactate increases only slightly at low work rates, and this increase is proportional to pyruvate increase (i.e. compatible with accelerated glycolysis without a change in redox state). At high work rates lactate increases disproportionately to pyruvate, the increased rate of lactate accumulation and lactate/pyruvate ratio appearing to occur at a threshold O2 consumption for a given individual. This symposium addresses the biochemical origin and physiological consequences of the increased lactate production during exercise.