Effects of oral lactate consumption on metabolism and exercise performance.

Study of lactate metabolism has revealed that orally consumed lactate is used as an energy substrate either directly by oxidation or by conversion to glucose. Disposal of lactate by oxidation or gluconeogenesis consumes protons and can fortify blood bicarbonate levels temporarily and increase pH. These characteristics have led to investigations of lactate consumption as an energy substrate and as a buffering agent. Evidence has revealed no effects of lactate consumption on time to exhaustion during low- to moderate-intensity exercise, suggesting that it is ineffective as an energy supplement. Lactate ingestion has been shown to increase blood pH and bicarbonate levels and increase time to exhaustion in short, high-intensity work bouts. Future work should focus on determining optimal doses of lactate, temporal relationships between doses and exercise, and the efficacy of lactate as an ergogenic in different types of high-intensity exercise.