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.

[Effects of competitive physical exercise on neuroendocrine response and interleukin-6 liberation in children]. / Repercusión del ejercicio físico competitivo en la respuesta neuroendocrina y liberación de interleuquina-6 en niños.

OBJECTIVE: The purpose of this study was to evaluate the effects of physical activity on the secretion of cortisol, melatonin and interleukin-6 (IL-6) in children. PATIENTS AND METHODS: A controlled prospective study was carried out. Based on anthropometrical measurements and physical examination, which excluded those with an organic pathology or that were further than one standard deviation from the 50th percentile, 74 male children aged 6 or 7 years were included in this study. Forty-one children from a public school (PS) and 33 children from a soccer sport school (SS) were selected and asked to perform three different physical activities. A score was made to evaluate their performance and both before and after physical activity salivary samples were obtained to measure cortisol, melatonin and IL-6 concentrations. RESULTS: The children in the SS group had a better global physical performance score than those from the PS. There were no statistically significant differences in biochemical parameters between the two groups before and after exercise. There was a rise in the cortisol, melatonin and IL-6 levels after physical activity in both groups. The increment in melatonin levels after exercise was significantly higher in the SS group. There was a strong positive correlation between the rise of cortisol and IL-6 levels after exercise. CONCLUSIONS: In our study, controlled physical competitive activity in children 6 or 7 years of age showed no negative repercussion on cortisol secretion or in the liberation of IL-6.

[Effects of physical exercise on the cardiorespiratory system in children]. / Repercusión cardiorrespiratoria del ejercicio físico en niños.

OBJECTIVE: Our aim was to perform a prospective study to evaluate the effects of competitive sports on the cardiorespiratory system and physical performance in children. PATIENTS AND METHODS: Male children aged 6 and 7 years were selected from a public school (PS) and from a soccer sports school (SS). They underwent anthropometrical measurement. Those boys who were further than one standard deviation from the 50th percentile were excluded from the study. A total of 74 boys were selected with 41 being from the PS and 33 from the SS. Three different physical competitive activities were performed by the children. Hemodynamic measurements [heart rate (HR), systolic, mean and diastolic blood pressure (SBP, MBP and DBP)] and respiratory measurements [respiratory rate (RR), arterial oxygen saturation (SatO2), peak expiratory flow (PEF), forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and the FEV1/FVC relationship] were taken before and after the physical activity. RESULTS: Overall we found a significantly higher physical performance in the SS group (p < 0.001). The HR before and after exercise was significantly lower in the SS group. The comparison between constants before and after physical activity in each group showed a significant increase in HR, SBP, MBP and DBP in the PS group, but there was no difference between the SBP before and after physical activity in the SS group. The SS group had a significantly lower RR and better SatO2 in the basal measurement. The relationship between constants before and after physical activity showed a rise in the PEF in the PS group and a decrease in the SatO2 in the SS group. CONCLUSIONS: We recommend controlled physical competitive activity in children because of its benefits on cardiorespiratory function and the absence of adverse effects.