Human antioxidative system kinetics of continuousα-lipoic acid supplementationof during extreme endurance running

[[abstract]]Purpose: To investigate the effects of continuous oral supplementation of alpha-lipoic acid on human antioxidative enzyme activities and lipid peroxidation during extreme endurance running. Methods: A randomized double-blind study was carried out on 13 recreational long-distance runners who were continuously and orally supplemented with placebo (CON, n = 6) or alpha-lipoic acid (LA, n = 7) up to 1600 mg (200 mg for the first 1-7th supplementation and 100 mg for the 8, 9th supplementation) in a 100-km supermarathon race. Heart rates were monitored during running and the plasma concentrations of malondialdehyde (TBARS), glucose, lactate, creatine kinase, as well as antioxidant enzyme activities in red blood cells including superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT) were measured 20 min before and at various distances (at 12, 24, 36, 48, 60, 72, 84, 96 and 100 km). Independent t test, mixed design of two-way (group × distance) ANOVA were used for data analysis. Results:. After continuous supplementation of α-lipoic acid in extreme endurance running, plasma lactate, creatine kinase and exercise performance showed no significant differences between groups. TBARS in ALA group (3.65 ± 2.03 uM) was significantly lower than CON group (4.88 ± 2.84 uM)(p < .05). Plasma glucose in ALA group ( 140.95 ± 14.89 mg?dL-1) was significantly higer than CON group (130.70 ± 16.11 mg?dL-1)(p < .05). Erythrocyte SOD activity in ALA group (4461.99 ± 677.22 U?gHb-1) was significantly lower than CON group (5143.49 ± 554.10 U?gHb-1)(p < .05). Erythrocyte GPx activity in ALA group (125.72 ± 22.43 kU?gHb-1) was significantly higher than CON group (59.32 ± 28.20 kU?gHb-1)(p < .001). Erythrocyte CAT activity in ALA group (24.27 ± 11.32 kU?gHb-1) was significantly lower than CON group (42.56 ± 10.10 kU?gHb-1)(p < .001). Conclusion:. Runners of 100-km road race benefited from LA supplement with lowered lipid peroxidation and increased GPx activity during exercise. Key words:α-lipoic acid, extreme endurance running, oxidative damage