Optimisation of the Heart Rate Variability Research Protocol for Assessing the Psychoemotional and Neurovegetative State of Military Personnel

Introduction. Heart rate variability (HRV) analysis is a reliable objective method for assessing the functional state of neurohumoral regulation. Aim. To improve the HRV research protocol and identify the relationship between extreme values of psychoemotional state indicators and HRV indicators. Materials and methods. A total of 57 military personnel (44.8±1.1 y.o.) were assessed for their psychoemotional state, the severity of vegetative dysfunction and sleep disorders, and HRV (lying down for 5 minutes and sitting for 3 minutes). Results. An association was found between the presence of pronounced vegetative disorders and an increased level of centralization of heart rate control, activation of subcortical sympathetic ergotropic centers, a pronounced decrease in total HRV, a significant decrease in parasympathetic nervous system tone, and a significant decrease in the McCraty index. The correlations found between most parameters of the psychoemotional state and HRV parameters were equivalent for HRV studies both in the horizontal position of the body for 5 minutes and in the sitting position for 3 minutes. However, the severity of vegetative disorders correlated more strongly with HRV indicators obtained in a lying position. A severe degree of nighttime sleep disturbance was more strongly associated with the McCraty index in HRV studies in a sitting position. Conclusions. In military personnel, there are reliable correlations between extreme values of psychoemotional and neurovegetative state indicators and HRV when recording the rhythmogram both in a horizontal position (5 minutes) and in a sitting position (3 minutes). Improvement of the standard protocol for clinical and psychophysiological HRV testing in a horizontal position for 5 minutes, with the addition of a 3-minute HRV study in a sitting position, made it possible to obtain a new, more complete assessment of the functional state of neurovegetative regulation and to justify the possibility of reducing the examination time. The use of a separate 3-minute HRV recording in a sitting position may be acceptable in conditions of time constraints and lack of adequate conditions for conducting HRV research in a lying position, when conducting psychophysiological and hygienic research in the workplace, in military field conditions, as well as when conducting mass field screenings of the population's health status.