Analysis of heart rate variability in medical students with different types of hemodynamics and body mass index values

Background: Adaptation of medical students to high school education is a serious medical and social problem.Serious stress, unbalanced diet and physical inactivity may result in disorders of the body's regulatory systems, as well as metabolic disorders, which may contribute to the development of cardiovascular diseases.Existing hemodynamic heterogeneity of the population also contributes to the response of the body to stressful factors.The aim of the study: To evaluate the specifics of heart rate variability (HRV) in medical students with different types of hemodynamics and body mass index values.Materials and methods: 170 second-and third-year students of the North Ossetian Medical Academy were enrolled in an observational study during the time of their preparation for exams.Blood pressure and anthropometric parameters were measured, and HRV (short-term recordings) was analyzed.After ranking the students by the types of hemodynamics, HRV parameters were estimated depending on the body mass index values.Results: The majority of medical students enrolled in the study were shown to have a eukinetic type of hemodynamics (60.6%), whereas 36.5% and 2.9% had hypokinetic and hyperkinetic types of hemodynamics, respectively.ANOVA on ranked data showed intergroup differences in both temporal and frequency HRV variables.The students with hypokinetic and eukinetic hemodynamics demonstrated higher values of MxDMn, HF, , SDNN, RMSSD, pNN50%.In the group with hyperkinetic hemodynamics, TP (843.89(397.24;1665.36)) was less than half of that in the other groups, while SI (336.28 (194.07;404.51)) and RSAP (6.50 (5.00; 7.00)) were higher compared to the other groups.Conclusion: Medical students demonstrated an increase in the tone of the sympathetic autonomic nervous system and a predominance of central regulatory mechanisms over autonomic ones, which was particularly evident in students with the hyperkinetic type of hemodynamics.Some HRV parameters worsen with higher BMI in students with different types of hemodynamics.Higher frequency of eukinetic and hypokinetic types of hemodynamics (which are less energy-consuming) may indicate a contribution of adaptive mechanisms of the cardiovascular system functioning during the period of preparation for exams.