Changes in blood antioxidant status and lipid peroxidation following distance running

643 Abstract: To examine the effects of increased O 2 utilization on blood antioxidant status and lipid peroxidation, ten trained male athletes took part in a 20 km distance race. Venous blood samples were removed before and immediately after completion of the half-marathon. Plasma creatine kinase (CK) activity, an index of muscle damage, increased (p<0.05) after the race but this was not accompanied by changes in thiobarbutiric acid reactive substance (TBARS), which is an index of lipid peroxidation. Plasma cholesterol and uric acid concentrations significantly increased (p<0.01 and p<0.05 respectively) but plasma α-topocherol, triglyceride, and the total protein levels did not change (p>0.05) after the race. The erythrocyte and leucocyte counts, hematocrit, and hemoglobin levels rose after the race (p<0.05, p<0.001, p<0.05, and p<0.01, respectively). However, the mean corpuscular volume (MCV), and mean corpuscular hemoglobin concentration (MCHC) did not change. Erythrocyte superoxide dismutase (SOD) and catalase activities were unaffected by the exercise but total glutathione (GSH) and reduced GSH decreased (p<0.05) after the race. In the post-race samples, a rise in oxidized glutathione (GSSG) was not statistically significant (p>0.05).