N-acetylcysteine attenuates the decline in muscle Na , K -pump activity and delays fatigue during prolonged exercise in humans

Abstract

Reactive oxygen species (ROS) have been linked with both depressed Na+,K+-pump activity and skeletal muscle fatigue. This study investigated N-acetylcysteine (NAC) effects on muscle Na+,K+-pump activity and potassium (K+) regulation during prolonged, submaximal endurance exercise. Eight well-trained subjects participated in a double-blind, randomised, crossover design, receiving either NAC or saline (CON) intravenous infusion at 125 mg kg-1 h-1 for 15 min, then 25 mg kg-1 h-1 for 20 min prior to and throughout exercise. Subjects cycled for 45 min at 71%, ̇VO2peak then continued at 92% until fatigue. Vastus lateralis muscle biopsies were taken before exercise, at 45 min and fatigue and analys..