Lipid peroxidation and antioxidative vitamins under extreme endurance stress

The aim of this study was to examine whether extreme endurance stress of trained athletes can influence lipid peroxidation and muscle enzymes. A randomized and placebo-controlled study was carried out on 24 trained long-distance runners who were substituted with alpha-tocopherol (400 I.U. d-1) and ascorbic acid (200 mg d-1) during 4.5 weeks prior to a marathon race. The serum concentrations of retinol, ascorbic acid, beta-carotene, alpha-tocopherol, malondialdehyde (TBARS) and uric acid as well as glutathione peroxidase (GSH Px) and catalase were measured 4.5 weeks before (A), immediately before (B), immediately after (C) and 24 h after (D) the course. After competition (C) TBARS serum concentrations of the athletes (n = 22) decreased in both groups (P < 0.0001). The ascorbic acid serum concentration increased significantly in the supplemented group from (A) to (B) (P < 0.01), from (B) to (C) (P < 0.001) and in the placebo group a significant increase from (B) to (C) (P < 0.01) was observed. The alpha-tocopherol serum concentration increased significantly in the supplemented group from (A) to (B) (P < 0.001) and from (B) to (C) (P < 0.05). The enzymes glutathione peroxidase (GSH Px) and catalase measured in erythrocytes as well as the serum selenium levels did not show significant differences at any time. A significant increase of CK concentration was observed from (C) to (D) in the supplemented group (P < 0.01) and in the placebo group (P < 0.001). The increase of CK serum concentration is remarkably lower in the supplemented group compared with the placebo group (P < 0.01). It is concluded that endurance training coupled with antioxidant vitamin supplementation reduces blood CK increase under exercise stress.