Cardiorespiratory fitness and oxidative stress: effect of acute maximal aerobic exercise in children and adolescents

Evaluate the effects of oxidative stress in saliva in young males, according to their cardiorespiratory fitness and taking acute maximal aerobic exercise into consideration. An incremental exercise test (20 meter shuttle run) was used. Seventy healthy male subjects, aged 10 to 14 years, were included in the study and were classified into two groups according to fitness parameters. Subjects were expected to take the 20 meter shuttle run test. Group I had high cardiorespiratory fitness while group II had low cardiorespiratory fitness below the mean for their age. Saliva samples were taken before and immediately after exercise in order to measure levels of reduced glutathione, lipoperoxides, glutathione/lipoperoxides ratio and catalase. The values of reduced glutathione were significantly diminished regardless the subjects' cardiorespiratory fitness. The glutathione/lipoperoxides ratio was significantly diminished in group I. In addition, positive correlations were observed between lipoperoxides values after the 20 meter shuttle run test. High cardiorespiratory fitness does not seem to be an essential factor effecting in the oxidative stress values before exercise. However, oxidative stress could be greater with more intensity and duration after and acute maximal physical exercise.