Assessment of system's adaptive reserves by indicators of heart rate variability in young men at the initial stages of university education

The purpose of the study is to assess the activity index of regulatory systems and mechanisms of neurohumoral regulation of heart activity in healthy young men at the initial stage of university education. Material and Methods. We studied the activity index of regulatory systems (PARS) and features of the mechanisms of neurohumoral regulation of cardiac activity on a sample of 150 young men [19.0 (18.0; 19.0) years old], based on the analysis of heart rate variability. Results. 40.0% (n=60) of young men had a satisfactory state of adaptive reserves of the body, 23.3% (n=35) were in a state of low functional stress, 24.7% (n=37) had poor adaptation, and 12.0% (n=18) failed to adapt. Conclusion. In male students with satisfactory, tense, and unsatisfactory adaptation, as disadaptation increases, the total effect of all levels of regulation on the heart rate increases with an increase in the effect on the cardiac activity of the parasym-pathetic division of the ANS and a decrease in the activity of cerebral subcortical structures responsible for adaptation, against the background of an increase in psychoemotional stress. In healthy male students, the disruption of systems' adaptive reserves is often accompanied by the total decrease in all levels of regulation with a predominance of sympathetic influences on the heart rhythm and is less frequently associated with a sharp increase in all levels of regulation and the predominance of parasympathetic division of the ANS for the CVS.