ABSTRACT
Exercise in high altitude and hypoxia decreases aerobic power and increases oxidative stress and lactic acid. Due to the metabolic and antioxidant properties of L-Carnitine, the purpose of this study was to investigate the effect of short-term L-Carnitine supplementation on endurance performance and cell damage in acute hypoxia. For this purpose, 16 active men after VO2max measurement in normoxia were divided into 2 groups of supplement and placebo. Supplement group received L-Carnitine and placebo group received placebo [sugar] for 10 days [3 g every day]. After eight days of supplementation period, VO2max in hypoxia condition was determined as well as normoxia. Then 1 day after supplementation, individuals participated in submaximal test [60%VO2max for 1 hour]. Blood samples were taken before, immediately after and 1 hour after recovery for determining lactic acid, lactate dehydrogenase [LDH], creatin kinase [CK] and malondialdehyde [MDA]. The result showed that short-term supplementation with L-Carnitine had no effect on VO2max [p=0.83], respiratory exchange ratio [RER] [p=0.314] and lactic acid, but it caused significant decrease in LDH [p=0.001], CH [p=0.001] and MDA [p=0.001] after submaximal activity. It can be concluded that short-term supplementation of L-Carnitine doesn't influence VO2max and lactate, but it may decrease cell damage.
ABSTRACT
In skeletal muscle, carnitine plays an essential role in translocation of long-chain fatty-acids for subsequent beta-oxidation; in addition, coenzyme Q10 [ubiquinone, CoQ10] is a component of the mitochondrial electron transport chain and also an important antioxidant. Despite abundant literature describing the basic mechanism of L-carnitine and CoQ10 metabolism, there remains some uncertainty regarding the effect of oral L-carnitine and CoQ10 supplementation. The aim of this study was to investigate effect of CoQ10 and L-carnitine supplementation on aerobic and anaerobic exercise performance in healthy inactive collegiate men. In a randomized double-blind placebo-controlled trial, 40 subjects [age: 23.01 +/- 2.97 y, weight: 72.9 +/- 11.71 kg and height: 176.80 +/- 5.36 cm] participated in two test sessions separated by 10 days. Subjects were randomly allocated into parallel groups to receive either CoQ10 [3 mg/kg/day], L-carnitin [30 mg/kg/day], both of them, or placebo, for 10 days. A 30-second Wingate anaerobic capacity test for determination of fatigue index [FI], and a maximal cardiopulmonary graded exercise test [modified Bruce protocol], for direct determination of VO2max by gas analyzer, were performed on the day before and after supplementation period. Data was analyzed using repeated measures ANOVA and paired sample T test. Results showed that co-supplementation with L-carnitine and CoQ10 had a significant incremental effect on VO2max [p< 0.05]. In the L-carnitine group, VO2max showed a tendency to increase but it was not significant [p=0.096]. FI decreased by 7.7% with L-carnitine + CoQ10, compared with 4.9% increase in placebo group; however this difference was not statistically significant [p=0.099]. Only supplementation with L-carnitine could significantly improve the fatigue index [p<0.05]. Short term co-supplementation with L-carnitine and CoQ10 may improve aerobic and anaerobic exercise performance in inactive collegiate men