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.
Córdova is with the Dept. of Biochemistry and Physiology, School of Physical Therapy, University of Valladolid, Soria, Spain. Sureda is with the Research Group on Community Nutrition and Oxidative Stress and CIBEROBN (Physiopathology of Obesity and Nutrition), University of Balearic Islands, Palma de Mallorca, Spain. Albina, Linares, Bellés, and Sánchez are with the Laboratory of Toxicology and Environmental Health, Rovira i Virgili University, Reus, Spain.