Lactate: valuable for physical performance and maintenance of brain function during exercise

Abstract

Lactate accumulation has long been associated with impaired sports performance, with many supporting the lactate acidosis hypothesis. However, due to advances in experimental design and research, numerous beneficial roles of lactate have been established that may impact upon sports performance. Recent studies highlight lactate as a biomarker of fatigue rather than as a direct cause. The lactate-shuttle mechanism facilitates the utilization of lactate as an energy substrate in both type I and type II skeletal muscle fibres, promoting energy sufficiency during exercise. Recent literature also supports a role for lactate in enhancing human oxidative capacity by up-regulating skeletal muscle mitochondrial biogenesis. In addition, lactate-neuron and lactate-astrocyte shuttles enable lactate to supply energy to support cognitive function, during periods of low blood glucose such as prolonged aerobic exercise. This review aims to clarify the role of lactate in modulating aerobic performance and critically investigates the mechanisms responsible.