The effect of chronic L-Carnitne supplementation on plasma glucose and lactate during exercise

In skeletal muscle, carnitine plays an essential role in the translocation of long-chain fatty-acids into the mitochondrial matrix for subsequent beta-oxidation. Despite an abundance of literature describing the basic mechanisms of action of L-carnitine metabolism, there remains some uncertainty regarding the effects of oral L-carnitine supplementation on metabolism and exercise performance in normal subjects. This study examined the effects of chronic L-carnitine supplementation on glucose and lactate concentration, heart rate and aerobic capacity during submaximal cycling. Thirty healthy and male students cycled for 20 min at 70% VO2 max before and after 3 weeks (3g daily) L-carnitine (experimental) and placebo (control) supplementation. Blood samples were taken immediately after each exercise for the purpose of calculation plasma glucose and Lactate concentration, lactate dehydrogenase activity (LDH). A two-way repeated measure ANOVA was used to determine significant differences between the two groups (p<0.05). The finding of our study showed that L-carnitine supplementation had no influence on plasma glucose and lactate. Also rest and rest heart rate, VO2 max and LDH activity was equal in pre and posttests (p<0.05). All variables were unaffected in the control trial. Three weeks L-carnitine supplementation had no effect on substrate and carbohydrate metabolism. Also, L-carnitine supplementation would be unlikely to be associated with the enhanced exercise performance.