Changes in heart rate variability in response to muscular load and their correlation with the concentration of steroid hormones in young males with different training specifics

Aim. The aim of this article is to study the peculiarities and correlations of vegetative and hormonal mechanisms of restoration after muscle activity in the athletes of different specializations and young males not involved in sports. Materials and methods. The research involved 47 male volunteers aged 17-24 years, including 34 athletes of high qualification and 13 relatively healthy men not involved in sports. The participants were divided into three groups according to their sport specialization: athletes improving speed-strength qualities, athletes involved in endurance sports, and the control group. As a model of acute muscle strain, we proposed 30-minute ergometer tests based on 2 W load per one kilogram of the body weight for a group of athletes and 1.3-2 W for untrained young males. We recorded RR intervals and hormone content under normal conditions, after load and an hour after the recovery. Results. Analyzing the temporal and frequency characteristics of HRV, we obtained similar results, demonstrating significant differences between the groups for each period of observation. We registered return to pre-exercise values of HRV within groups after 60-minute recovery. We established an inverse correlation between HRV and the concentration of cortisol and testosterone in blood plasma as a result of muscular load and subsequent recovery. Conclusion. HRV depends directly on the training level and body adaptation to aerobic loads: there is an increase in the progression “control - speed-strength - endurance”. The most obvious correlation was observed between HRV and cortisol. The correlation of HRV and testosterone may be mediated by the direct correlation of hormones relative to each other.