THE EFFECT OF L-CARNITINE SUPPLEMENTATION ON PLASMA CARNITINE LEVELS AND VARIOUS PERFORMANCE PARAMETERS OF MALE MARATHON ATHLETES

The effect of L-carnitine supplementation on the plasma carnitine leve ls and various performance parameters of seven male marathon athletes was investigated. Each athlete completed two progressive treadmill tes ts to exhaustion, separated by a six week supplementation period (2g L -carnitine/day). During the treadmill tests peak treadmill running spe ed, oxygen consumption, cardiovascular responses, respiratory exchange ratio and plasma carnitine levels were monitored. After supplementati on peak treadmill running speed increased by 5.68%, average oxygen con sumption (VO2) and heart rate decreased, and respiratory exchange rati o values showed a declining tendency. After supplementation plasma acy l-, total- and percentage bound carnitine levels increased significant ly, whereas free carnitine levels increased but remained below the nor mal range. Findings from this study suggest that L-carnitine supplemen tation could positively influence aerobic capacity. Copyright (C) 1997 Elsevier Science Inc.