Exercise-induced oxidative stress affects erythrocytes in sedentary rats but not exercise-trained rats

Oxidant stress is one of the factors proposed to be responsible for damaged erythrocytes observed during and after exercise. The impact of exertional oxidant stress after acute exhaustive treadmill running on erythrocyte dama ge was investigated in sedentary (Sed) and exercise-trained (ET) rats treat ed with or without antioxidant vitamins C and E. Exhaustive exercise led to statistically significant increments in the levels of thiobarbituric acid- reactive substance (TBARS) and H2O2-induced TBARS in Sed rats and resulted in functional and structural alterations in erythrocytes (plasma hemoglobin concentrations, methemoglobin levels, and rise in osmotic fragility of ery throcytes with decrease in erythrocyte deformability). Administration of an tioxidant vitamin for 1 mo before exhaustive exercises prevented lipid pero xidation (TBARS, H2O2-induced TBARS) in Sed rats without any functional or structural alterations in erythrocytes. Parameters indicating erythrocyte l ipid peroxidation and deterioration after exhaustive exercise in rats train ed regularly with treadmill running for 1 mo were not different from those in Sed controls. Erythrocyte lipid peroxidation (TBARS) increased in exhaus ted-ET rats compared with ET controls; however, the plasma hemoglobin, meth emoglobin levels, and erythrocyte osmotic fragility and deformability did n ot differ. Exhaustive exercise-induced lipid peroxidation in ET rats on ant ioxidant vitamin treatment was prevented, whereas functional and structural parameters of erythrocytes were not different from those of the ET control s. We conclude that exertional oxidant stress contributed to erythrocyte de terioration due to exercise in Sed but not in ET rats.