HEART RHYTHM REGULATION IN FIRST-YEAR STUDENTS OF DIFFERENT ETHNIC GROUPS PROVIDING FOR THE POWER STRUCTURE OF TOTAL SPECTRUM
The investigation of the activity of the central and autonomous mechanisms of heart rhythm regulation as parameters of adaptation to the academic activities of students of various ethnic groups has both theoretical and practical significance. The objective of the paper is to assess the role of central and autonomous mechanisms in heart rate regulation in first-year students of various ethnic groups by parameters and power structure of the total spectrum of heart rate variability (HRV). Materials and Methods. The study consisted of two stages and included 120 students (21-23 year of age) of three ethnic groups (Arabic, Latin American, and Russian). The study was conducted in October and April of the 2016-2017 academic year. The Poly-Spectrum-Rhythm software module was used to record a 5-minute ECG. Then the author examined spectral characteristics of HRV parameters for each student and divided the obtained characteristics into subgroups in each ethnic group, taking into account the leading type of autonomous heart rhythm regulation. Heart rhythm was determined according to individual values of voltage index and absolute power of very low frequencies. Results. At both stages, the third type of autonomous heart rhythm (HR) regulation dominated in Russian students. In Arab and Latin American students, the third (moderately prevailing parasympathetic autonomic regulation (MPPAR)) or fourth (strongly predominant parasympathetic autonomic regulation (SPPAR)) types were equally determined. In Latin American students, the first type with a moderate manifestation of central regulation (MMCR) of the heart rhythm was observed at both stages. In all ethnic groups of students with MPPAR and SPPAR of the heart rhythm, the power structure of the frequency components of the total neurohumoral regulation spectrum deviated from the norm. Conclusion. During the academic year, Arab students with MPPAR of the heart rate demonstrated a slight decrease in initially dominant central contour with a pronounced manifestation of sympathicotonia; Latin American students demonstrated increase in parasympatheticotonia; while Russian students demonstrated increased sympathicotonia. In subjects with MPPAR of the heart rate, the initial level of parasympathicotoni, manifested on the background of a high voltage of the central circuit of heart rhythm regulation, contributed to stress development in Arabs and Russians and the adaptation mechanism breakdown in Latin Americans.