OBJECTIVE

To analyze the heart rate variability in young people with different cardiovascular system adaptation reserves and identify statistically significant parameters.

MATERIAL AND METHODS

In the study, 257 volunteers had their blood pressure levels, heart rate, and anthropometric indicators measured, and their body mass index and adaptation potential (AP) were calculated. Based on the AP levels, the participants were divided into 3 groups: Group 1 (controls, AP1) included young people with satisfactory adaptation (AP≤2.6) — n=42; Group 2 (AP2) included people with a stress on adaptation mechanisms (2.6<AP<3.10) — n=40; and Group 3 (AP3) involved people with unsatisfactory adaptation (AP≥3.1) — n=32. Cardiointervalography (5-minute ECG recording) was performed at rest and during a functional hyperventilation test, and statistical data analysis was performed.

RESULTS

Lower RRNN, SDNN, NN50, and NN20 levels were associated with a lower cardiovascular AP. Changes in indexes in Groups 2 and 3 evidenced decreased autonomic influences at increased sympathoadrenal tone. Against the background of respiratory modulation, the differences between the RRNN and SDNN were leveled; heart rate variability increased in all groups; the maximum changes in the respiratory modulation index were recorded in individuals with unsatisfactory adaptation.

CONCLUSIONS

Young people with stress on adaptation mechanisms or with unsatisfactory cardiovascular system adaptation have a decreased influence on parasympathetic regulation, which correlates with increased arterial blood pressure. The heart rate variability analysis as a premorbid diagnostic method can reveal signs of cardiovascular pathology at the development of autonomic dysfunction before organic changes in the myocardium.