Serum oxidant and antioxidant status during early and late recovery periods following an all-out 21-km run in trained adolescent runners

It is well documented that intense exercise precipitates oxidative stress in adults. However, there is lack of related studies concerning oxidant and antioxidant status during early and late recovery periods in adolescent athletes, following endurance exercise in particular. This study investigated aspects of the serum oxidant and antioxidant status of 12 male adolescent (16.2 ± 0.6 years) trained runners during early and late recovery periods after an all-out 21-km run. Venous blood samples were taken immediately before, 2 and 4 h following (early recovery period), and 24 h following (late recovery period) the 21-km run. Samples were analyzed for serum concentrations of thiobarbituric acid-reactive substances (TBARS), uric acid (UA), reduced glutathione (GSH), and enzymatic activity of xanthine oxidase (XO), superoxide dismutase (SOD), and catalase (CAT). During the early recovery period, there were increases in the 4-h GSH (194.8 ± 10.4 vs. 211.8 ± 11.4 mg l^-1, P < 0.05), 2-and 4-h UA (307.8 ± 68.6 vs. 327.4 ± 63.8; 330.2 ± 65.1 μmol l^-1, P < 0.05), and 2-h CAT (2.05 ± 0.44 vs. 3.07 ± 0.51 U ml^-1, P < 0.05), and decreases in the 2-h XO (11.1 ± 1.5 vs. 10.3 ± 1.2 U l ^-1, P < 0.05) compared to the corresponding pre-exercise level, respectively. No change was observed in SOD (P > 0.05). At the late recovery period, there was an increase in CAT (2.80 ± 0.49 U ml^-1, P < 0.05) and TBARS (2.99 ± 0.83 vs. 4.40 ± 1.38 nmol ml ^-1, P < 0.05). These data indicate that although the antioxidant capacity of adolescent runners is augmented during the early recovery period following the 21-km run, they were not completely protected from oxidative stress during the later recovery period.