HEART RATE REGULATION DURING ADAPTATION TO CONDITIONS IN ANTARCTICA

The article deals with topical issues of the problem of studying the mechanisms of human adaptation to Аntarctic conditions, in particular, the characteristics of the restructuring regulation of cardiovascular system during expedition activity at the Ukrainian Antarctic Station «Academic Vernadsky». The studies were performed directly in Antarctica with the participation of winterers, who during a year were surveyed monthly by cardiointervalography and ECG. As a result of analysis of variance of heart rate in Antarctic conditions we identified the phasic restructuring of the regulation of heart rhythm of winterers. The findings extend the understanding of the peculiarities of realization of regulating the circulatory system during the change of adaptation phases. In particular, the RRNN index has a phasic structure and ranges ± 7-9 c.u. from the beginning of wintering, and in the last phase is increased to -32 c.u. The activity of the development of stress condition among winterers reflects the dynamics of changes in the rate ІNt function, which from the beginning of wintering till January ranged from 2-5 c.u. by modulo, and in the months before the return (February, March), the rate reached 46 c.u. It is established a dominant role of the time factor in influencing the quality adjustment of adaptation processes. While during the first half of the expedition heart rate variability had a balanced regulatory influence, at the end of the expedition an increased activity of the sympathetic division of the autonomic nervous system and stress regulatory mechanisms were observed. This may indicate for incomplete adaptation that requires the application of methods of correction of functional state.