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 10-13 years 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(®) ). Children were dichotomized into two groups, based on their individual weekly time spent in a sports club: low-volume group < 180 min/week (N = 26) and high-volume group ≥ 180 min/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.