Uniform and prolonged changes in blood oxidative stress after muscle-damaging exercise.

BACKGROUND The effect of eccentric exercise on the time-course changes in several indices of muscle damage and blood oxidative stress was examined. MATERIALS AND METHODS Isometric torque, delayed-onset muscle soreness, creatine kinase, reduced glutathione (GSH), oxidized glutathione (GSSG), thiobarbituric-acid reactive substances (TBARS), protein carbonyls, catalase, uric acid, bilirubin and total antioxidant capacity (TAC) in blood were measured pre-, 24 h, 48 h and 72 h post-eccentric exercise of knee extensors in ten females. RESULTS The concentration of all oxidative stress indices changed significantly in a way indicating increased oxidative stress in the blood (GSH and GSH/GSSG, decreased, whereas GSSG, TBARS, protein carbonyls, catalase, uric acid, bilirubin and TAC increased) peaking, in all but TBARS, at 48 h and returning toward baseline afterwards. CONCLUSION We believe that muscle-damaging exercise should be viewed as a different challenge compared to non-muscle-damaging exercise with regard to its effects on blood oxidative stress.