Introduction The aim of the study was to analyze the changes in the indices of the autonomic nervous system and the adaptive capacity of Ukrainian Super League handball players prior to significant competitions. Material and methods This research involved 39 handball players from the Ukrainian Super League aged 18–22 years old. The study examined the overall tone of the autonomic nervous system (ANS ) measuring electrodermal activity of the athletes. Reactivity of the ANS of players was monitored by the method of R. Baevskyy, the efficiency of competitive activity in handball was analyzed by the integral index of technical and tactical handball skills. Results Before the competition, the reaction in the sympathoadrenal system was launched for vagotonics as the intended response to the upcoming games. The measured indicators marked mental stress and activation of the sympathoadrenal system for the sympathotonics group. The аtonics group provided the emotional ground due to the balanced influence of para- and sympathetic divisions of the autonomic nervous system. Conclusions The index of functional changes in all participants detected a satisfactory level of adaptation. The highest sympathetic activity was observed for аtonics, the lowest – for vagotonics. The best results were documented for athletes who did not have autonomic dysfunction and those who had a slight predominance of the sympathetic component of the autonomic regulation.