Plasma oxidative stress (hydrogen peroxide/trolox) responses during a 7-day road cycling stage race and a competitive football match in top-level athletes

Purpose: The aim of this study was to compare the response induced by regular competition on free oxygen radicals (hydrogen peroxide), free oxygen radical defence (Trolox) and hydrogen peroxide/Trolox balance in plasma, between top-level male road cyclists and top-level male football players. Methods: 9 male top-level road cyclists (age 27.2 ± 3.5 years) and 10 male top-level football players (age 27.3 ± 4.3 years) completed a 7-day road cycling stage race and a football match, respectively. Free oxygen radicals (hydrogen peroxide) and free oxygen radical defence (Trolox) were measured 2 h before and 1 h after the corresponding competition. Body composition was determined previously by means of dual-energy X-ray absorptiometry. Results: Both competitions induced a significant increase in hydrogen peroxide for each group. Trolox decreased and hydrogen peroxide/Trolox balance increased, significantly, for road cyclists. For football players, Trolox increased and hydrogen peroxide/Trolox balance decreased, significantly. Hydrogen peroxide/Trolox balance differences had a significant positive correlation against respective competitive loads for both groups. Hydrogen peroxide differences showed a significant negative correlation and Trolox differences indicated a significant positive correlation with body mass index, body fat, and lean body mass. Conclusions: This study suggests that football players may be able to maintain oxidative stress balance in plasma after a football match whilst road cyclists may experience a hyper-oxidative stress state in plasma after a 7-day road cycling stage race. In addition, both, competitive load and body mass are related to the oxidative stress balance in plasma in these two groups of top-level athletes.