Special Aspects of Vegetative Support of Cardiac Activity in Volleyball Players with Hearing Impairment: a Longitudinal Comparative Study

INTRODUCTION. Team sports are an important part of adapting activities for athletes with hearing impairment. However, it is necessary to take into account the focus and intensity of physical activity in athletes with hearing impairment, since sports activities can have a modulating effect on the functioning of the circulatory system, the vegetative balance of the athlete’ body. AIM. To study the features of heart rate variability and reactivity of the autonomic nervous system in the regulation of heart rate in athletes with hearing impairment. MATERIALS AND METHODS. Male highly qualified volleyball athletes with congenital sensorineural hearing impairment (26.42 ± 1.38 years old) were examined in a longitudinal controlled study. The comparison group was represented by male volleyball players without hearing impairment. The design of the study included a survey of volleyball players in the transition and competitive phases of sports training. Studies of the autonomic regulation of the cardiovascular system were carried out on the basis of a five-minute recording of cardiac intervals in a horizontal position of the subjects using the Poly–Spectrum–12/E complex according to the generally accepted research protocol. RESULTS AND DISCUSSION. The study shews that the transition phases of sports training in volleyball players with hearing impairment was characterized by a low stress index (SI — 69.52 arb. unit). The values of HR (69.05 bpm), SDNN (58.50 ms), pNN50 (17.80 %), Mo (0.87 sec), AMo (35.85 %), CV (0.35 sec), PSD (3258.00 ms²) were within the normotonia. The competitive stage of training for athletes with hearing impairment was accompanied by a significant increase in SDNN (143.00 ms), Mo (1.07 sec), CV (0.94 sec), PSD (6078.00 ms²), VLF (3968.00 ms²), LF (1577.00 ms²) and a decrease in the stress index (15.76 arb. unit) compared with the group of volleyball players without hearing impairment. Regardless of the stage of sports training, the humoral-metabolic channel of regulation dominated the spectrum of cardionetrvals. CONCLUSION. The vegetative status of volleyball players with hearing impairment during the recovery period was characterized by moderate dominance of the autonomous regulation circuit with high activity of humoral and metabolic channels of heart rhythm regulation. During the competition period, significant differences in vegetative support were noted in athletes with hearing impairment, which were characterized by high variability and power of the spectrum of cardiointervals, the development of pronounced parasympathicotonia.