High-volume sports club participation and autonomic nervous system activity in children

Background Sixty minutes of daily moderate-to-vigorous physical activity (PA) are recommended for children. This study investigated the additional impact of high-volume sports club participation on the autonomic nervous system in active children, while controlling for acute effects of short-term PA. Materials and methods Forty-nine children (29 females) aged 10-13years were investigated. Sports club participation was assessed with a validated questionnaire. Short-term PA and night-time autonomic tone (spectral power and nonlinear analysis of heart rate variability) were measured with an ambulatory device (Actiheart((R))). Children were dichotomized into two groups, based on their individual weekly time spent in a sports club: low-volume group <180min/week (N=26) and high-volume group 180min/week (N=23). Results Children in the high-volume group exhibited higher indices of vagal tone compared with the children in the low-volume group. Short-term moderate PA had a significant impact on the night course of autonomic activity. Boys showed a linear increase in vagal activity over the night course in relation to volumes of short-term moderate PA of the previous day. A similar but nonsignificant trend was observed for girls. Conclusions In active children, higher volumes of sports club participation have an additional benefit on indices of autonomic tone.