Prepubertal children with suitable fitness and physical activity present reduced risk of oxidative stress.

To assess the impact of fitness status and physical activity on oxidative stress in prepubertal children, we measured selected biomarkers such as protein carbonyls (PC), lipid peroxidation products, and total nitrites, as well as the antioxidant system: total glutathione (TG), oxidized glutathione (GSSG), reduced glutathione (GSH), superoxide dismutase activity, and glutathione peroxidase. A total of 132 healthy children ages 7-12, at prepubertal stage, were classified into two groups according to their fitness level: low fitness (LF) and high fitness (HF). They were observed while engaged in an after-school exercise program, and a questionnaire was created to obtain information on their physical activity or sedentary habits. Plasma and red blood cells were obtained to analyze biomarkers. Regarding oxidative stress markers, the LF group and the sedentary group showed higher levels of TG and GSSG and a lower GSH/GSSG ratio than the HF group and the children engaged in physical activity. A negative association was found between PC and GSSG and TG and between TG and the GSH/GSSG ratio. Moreover, a negative correlation was found between GSSG and fitness, with a positive correlation with the GSH/GSSG ratio. TG, GSSG, and the GSH/GSSG ratio seem to be reliable markers of oxidative stress in healthy prepubertal children with low fitness or sedentary habits. This research contributes to the recognition that an adequate level of fitness and recreational physical activity in childhood leads to better health and oxidative status.

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

AIM: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

[Changes in oxidative stress biomarkers induced by puberty]. / Cambios en biomarcadores del estrés oxidativo inducidos por la pubertad.

AIM: Evaluate the influence of puberty in oxidative stress. SUBJECTS AND METHODS: The study included 38 prepubescent males with Tanner G(1)-P(1) and 32 healthy pubescent boys with Tanner G(3-4)-P(3-4). Weight, height and body mass index, heart rate, blood pressure values were within the 50 percentile 50+/-1SD for their age. The biomarkers were measured in saliva, as a good correlation between saliva and plasma levels has been reported in lipoperoxidation products, reduced glutathione and catalase. RESULTS: Pubescent boys had significantly higher levels of lipoperoxidation products (P<0.001) compared with the prepubertal group, with no significant differences in the other parameters measured. There was a significant positive correlation between lipoperoxides and reduced glutathione in these children. CONCLUSION: It is the first time that an increase of lipoperoxidation products has been reported in pubertal boys and this biomarker could play a role in the development of oxidative stress in this stage of life.