ABSTRACT
OBJECTIVE: We have determined the differences of the influence of prolonged exercise or higher intensity lactacidemic exercise, on plasma lipid peroxidation and on erythrocyte antioxidant enzymatic defence system. EXPERIMENTAL DESIGN: We measured plasma indices of lipid peroxidation, conjugated dienes (CD) and malondialdehyde (MDA) and erythrocyte enzymes superoxide dismutase (SOD), glutathione peroxidase (GSHPx) and catalase (CAT). The biochemical evaluations were performed in six healthy control males (C) and twelve athletes: six marathon runners (MR) and six sprint-trained athletes (STA) at rest and after a half-marathon (MR) and a training session of 6 x 150 m (STA). RESULTS: In resting conditions MDA was higher in STA and MR than in C (p < 0.01), while only the MR showed significantly elevated levels of CD (p < 0.05). In STA the enzymatic scavenging capacity showed a significantly higher SOD (p < 0.01) and GSHPx (p < 0.01), while CAT was lower than in controls (p < 0.05). In MR only SOD (p < 0.01) was significantly higher than in C. It increased significantly immediately after half-marathon, while CAT decreased 24 and 48 hours postexercise respectively. In these athletes the lipoperoxidative indices increased in the early postexercise phase, while at 24 and 48 hrs both CD and MDA levels decreased. In STA enzyme activities were not modified by anaerobic performance while CD showed a peak 6 hrs postexercise and the MDA showed a progressive increase until 48 hrs afterwards. CONCLUSIONS: Both strenuous long duration exercise and exhaustive sprint training overwhelm our capacity to detoxify ROS, producing oxidative stress. Thus an adequate supply of antioxidants could be appropriate.