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.