RESUMO
BACKGROUND: Exhaustive exercise has been implicated in the generation of reactive oxygen species, resulting in oxidative stress. We studied the effect of a long-distance, endurance exercise on oxidative stress parameters in athletes who participated in the ultramarathon race Spartathlon (246 km). MATERIALS AND METHODS: This study included 18 runners (16 men and 2 women) aged 42.8 +/- 1.4 years. Blood samples were obtained 24 h before (prerace), at the end (postrace) and 48 h after the end of the race (48 h postrace). We measured oxidative stress indices, including red cell glutathione, malonyldialdehyde and 8-iso-prostaglandin F(2a), as well as the total antioxidant capacity. RESULTS: 8-Iso-prostaglandin F(2a) level increased significantly at the end of the race, compared to prerace levels (up to 914.7 +/- 61.4 pg mL(-1) from 197.6 +/- 8.4 pg mL(-1)), and remained 2.5-fold increased over the baseline 48 h after the race (532.0 +/- 54.2 pg mL(-1), P < 0.000). The total antioxidant capacity of the athletes increased from a baseline of 289.6 +/- 9.0 micromol L(-1) to 358.7 +/- 11.0 micromol L(-1) immediately after the race and remained elevated 48 h later (350.6 +/- 7.6 micromol L(-1)) (P < 0.001). CONCLUSIONS: Prolonged exercise induces a marked response of oxidative stress biomarkers, which in part is compensated by serum ability to scavenge free radicals. Whether these changes have long-term negative effects in the organism needs further investigation.
