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.