Data on effects of statins on resting oxidant-antioxidant status are contradictory and no study has been published on the effects of statins on exercise-induced oxidative stress. We carried out a 6-month longitudinal study in 10 dyslipidemic patients receiving 10 mg/day atorvastatin and 13 healthy sedentary subjects. Thiobarbituric acid reactive substances (TBARS) and reduced ascorbic acid (RAA) were measured in plasma at rest and every 5 minutes after submaximal isometric thumb adduction and handgrip sustained until exhaustion. At inclusion, resting TBARS and RAA levels in controls and patients did not differ and exercise increased TBARS and decreased RAA. Atorvastatin reduced resting TBARS and RAA levels in a time-dependent but lipid-independent manner. The main effect was a post-exercise increase in TBARS, without affecting the post-exercise RAA levels. The reduction in oxidative stress occurred earlier in oxidative muscles involved in thumb adduction. In conclusion, atorvastatin lowers resting oxidant-antioxidant activity: exercise-induced oxidative stress occurs mainly in muscles having a high oxidative capacity.