N-acetylcysteine enhances muscle cysteine and glutathione availability and attenuates fatigue during prolonged exercise in endurance-trained individuals

Abstract

The production of reactive oxygen species in skeletal muscle is linked with muscle fatigue. This study investigated the effects of the antioxidant compound N-acetylcysteine (NAC) on muscle cysteine, cystine, and glutathione and on time to fatigue during prolonged, submaximal exercise in endurance athletes. Eight men completed a double-blind, crossover study, receiving NAC or placebo before and during cycling for 45 min at 71% peak oxygen consumption (V̇O 2 peak) and then to fatigue at 92% V̇O 2 peak. NAC was intravenously infused at 125 mg·kg -1·h -1 for 15 min and then at 25 mg·kg -1·h -1 for 20 min before and throughout exercise. Arterialized venous blood was analyzed for NAC, glutathione ..