Response of the Cardiovascular System to a Speed-Strength Exercise in a Cold Environment in Male Adolescents at the Age Stages of 14–15 and 15–16 Years

Abstract

The purpose of this study was to determine the reactivity of the cardiovascular system after a speed-strength exercise in cold conditions using short-term biofeedback (BF) training to increase total heart rate variability (HRV) in adolescents aged 14–15 years and the following year, when they turned 15–16. Materials and methods. Healthy male adolescents were examined twice with an interval of 1 year (14–15 years old and 15–16 years old). Blood pressure (BP) and HRV were recorded before and immediately after a thrice-repeated standing long jump in the open air (t = –1…–10 °C) as well as during the recovery period. In the recovery period, the experimental group underwent BF training (3 min) using Varikard equipment (Ramena, Russia) to increase the total HRV power; the control group stayed at rest. Results. In adolescents aged 14–15 years after exercise in cold conditions total HRV and sympathetic activity remained stable (p > 0.05); during the recovery period, a pronounced decrease in systolic BP and preservation of vagal activity were detected in the BF group, in contrast to the control. Adolescents aged 15–16 after exercise had a more pronounced rise in sympathetic activity compared with those aged 14–15 years (p < 0.05); in the BF group, the decrease in total HRV power was less pronounced than in the control, with vagal activity preserved. Thus, in 15–16-year-old adolescents after a speed-strength exercise in the cold sympathetic activity and a decrease in total HRV were more pronounced than in those aged 14–15 years. During the recovery period, a short-term BF training (3 min) aimed to increase total HRV power contributes to preserving vagal activity in adolescents at both age stages.