We investigated competitive- and long-term oxidative stress during a competition season in eight top-ranked members of the Austrian Men's Alpine Ski Team. Serum total peroxides, antibody titers against oxidized LDL (oLAb) and lag time of the degradation of the fluorophore 1-palmitoyl-2-((2-(4-(6-phenyl-trans-1,3,5-hexatrienyl)phenyl)ethyl)-carbonyl)-sn-glycero-3-phosphocholine were measured, along with plasma concentrations of ascorbate, alpha- and gamma-tocopherol, beta-carotene, uric acid and the lipid status. Competitive stress was indicated through an increased post-race uric acid level (286 +/- 50 microM pre-race vs 456 +/- 77 microM post-race, P<0.001) in December. Long-term effects were already apparent in November, with the highest concentrations of total peroxides (680 +/- 458 microM H(2)O(2) equivalents vs December 47 +/- 58 microM H(2)O(2) equivalents and January 15 +/- 28 microM H(2)O(2) equivalents, P<0.001) and a concomitant decrease in oLAb titers with an antibody trough in December (439 +/- 150 mU/mL vs baseline 1036 +/- 328 mU/mL; P=0.003). In January, after recovery, they attained nearly pre-season levels of oxidative stress biomarkers. This study indicates midseason oxidative stress in top-level skiers, which was associated with the performance in these athletes.