The aim was to determine the levels and activities of the oxidative stress markers in erythrocytes, plasma, and urine after a flat cyclist stage. Eight voluntary male professional trained-cyclists participated in the study. Exercise significantly increased erythrocyte, leukocyte, platelet, and reticulocyte counts. The exercise induced significant increases in the erythrocyte activities of catalase (19.8%) and glutathione reductase (19.2%), while glutathione peroxidase activity decreased significantly (29.3%). Erythrocyte GSSG concentration was significantly increased after exercise (21.4%), whereas GSH was significantly diminished (20.4%). Erythrocyte malondialdehyde levels evidenced a significant decrease 3 h after finishing the stage (44.3%). Plasma malondialdehyde, GSH and GSSG levels significantly decreased after 3 hr recovery (26.8%, 48.6%, and 31.1%, respectively). The exercise significantly increased the F2-isoprostane concentration in urine from 359 ± 71 pg/mg creatinine to 686 ± 139 pg/mg creatinine. In conclusion, a flat cycling stage induced changes in oxidative stress markers in erythrocytes, plasma, and urine of professional cyclists. Urine F2-isoprostane is a more useful biomarker for assessing the effects of acute exercise than the traditional malondialdehyde measurement.
Alfredo Córdova, Antoni Sureda, María L. Albina, Victoria Linares, Montse Bellés and Domènec J. Sánchez
Antoni Aguiló, Pere Tauler, Emilia Fuentespina, Gerardo Villa, Alfredo Córdova, Josep A. Tur and Antoni Pons
The aim of this work was to check the effects of antioxidant supplementation (vitamins E and C, and β-carotene) on the basal iron status of athletes prior to and following their training and competition season (3 months).
Eighteen amateur trained male athletes were randomly distributed in 2 groups: placebo (lactose) and antioxidant supplemented (vitamin E, 500 mg/d; vitamin C, 1 g/d; and β-carotene, 30 mg/d). The study was double blind. Hematological parameters, dietary intake, physical activity intensity, antioxidant status (GSH/GSSG ratio), and basal iron status (serum iron, transferrin, ferritin, and iron saturation index) were determined before and after the intervention trials.
Exercise decreased antioxidant defenses in the placebo group but not in the antioxidant-supplemented group. No changes were found in the number of erythrocytes, hematocrit, or hemoglobin concentration, or in values of serum iron parameters, after taking the antioxidant cocktail for 3 months, in spite of the exercise completed. The placebo group showed a high oxidative stress index, and decreases in serum iron (24%) and iron saturation index (28%), which can neither be attributed to aspects of the athletes’ usual diet, nor to hemoconcentration.
Antioxidant supplementation prevents the decrease of serum iron and the iron saturation index, and a link between iron metabolism and oxidative stress may also be suggested.