Background & objectives: The “redox” state represents the oxidation/reduction potential within the cell in a way that more “redox” is the marker of health, while the more oxidized reflects predisposition to diseases. Different types of exercise training may change the thiol/disulfide ratio of redox couples such as glutathione and represent a shift in redox balance. This study was assessed the influence of high-intensity aerobic exercise on glutathione redox state in red blood cells in professional, recreational athletes and nonathletes.

  Methods: Ten voluntary well trained (WT), moderately trained (MT) and untrained men subjectswere randomly selected for this semi-experimental study (mean ages of 21.10±1.72 21.70±1.88 and 20.10±1.44, respectively). Blood samples were collected before, immediately, 10 min and 30 min after acute aerobic exercise with 75%VO2max. The levels of reduced glutathione (GSH), oxidized glutathione (GSSG) and (GSH/GSSG) in red blood cells (RBCs) as well as serum levels of cortisol and creatine kinase (CK) were measured.

  Results: The results showed reduction, elevation and no changes in RBCs GSH/GSSG ratio in UT, MT and WT groups, respectively. The lowest levels of GSH/GSSG ratio in RBCs and the highest one were detected in the WT and MT groups, respectively. The serum levels of cortisol and creatine kinase were increased following the exercise in three groups.

  Conclusion: It is concluded that acute aerobic exercise with high intensity does not change redox balance in well trained subjects, however it is capable to shift redox balance towards more reducing environment in moderately trained subjects and also to more oxidizing one in untrained subjects.