Analysis of heart rate variability indicators in female students

The study analyzed heart rate variability (HRV) in 50 female students. The first group (control) included girls from Chernyanskiy district; the second, third and fourth groups (experimental) included girls from Belgorod district, Shebekinskiy and Yakovlevskiy urban districts of Belgorod region, respectively. The cardiointervalography indices according to R. M. Baevskyi were studied. The results showed that, compared to the first group, the heart rate of students in the second group was 6.62% lower, and in the fourth - 10.51%. The obtained heart rate values may indicate an adaptive response of the cardiovascular system to environmental pollution. AMO in female students of the second, third and fourth groups was 35.57%, 55.31% and 39.08% higher, respectively, than in the first group, which is observed with the dominance of the sympathetic division of autonomic nervous system in regulating heart activity and increasing the functional stress of the myocardium. PAPR in girls of the third group was 47.31% higher, compared with the first group. SI in subjects of the third group was 75.86% higher, compared with the first group. PAPR of the third group students indicate an increase in their centralization of heart rhythm control. In female students of the second and fourth groups, the value determining the mathematical expectation was 7.59% and 11.39% higher, respectively, than in the first group. These modes in girls of the fourth group were 20.0% higher than in the first group. The median in subjects of the second and fourth groups was 7.59% and 11.39% higher, respectively, compared to the first group. According to the mathematical expectation and the value dividing the variation series of intervals into two equal parts (median), the students of the second and fourth groups have a decrease in the adrenergic effect and sympathetic activity on the regulation of heart activity, compared to the first group, which can confirm the presence of compensatory mechanisms of adaptation to unfavorable environmental factors. The revealed differences between the groups of girls are influenced by the territorial features of residence associated with the type of industrial load and, as a consequence, emissions of various chemical compounds into the environment. The students living in Belgorod district, Shebekinskiy and Yakovlevskiy urban districts have a predominant effect of the parasympathetic division of the ANS on SR is observed, which may indicate the presence of adaptive mechanisms aimed at maintaining functional homeostasis.