Dynamics of heart rate variability indicators in participants of the Russian Antarctic expedition
Abstract
Research of adaptive processes in the human body under extreme climatic and geographical conditions is important both from the point of view of pathogenesis – the study of the mechanisms of response to the influence of pathogenic factors, and from the point of view of sanogenesis – the assessment of mechanisms aimed at preventing the action of a pathogenic agent.
The purpose of the study is to study the dynamics of heart rate variability (HRV) over 2.5 months of the Antarctic expedition (from November 17, 2022 to February 1, 2023).
Methodology. Three participants of the 68th Russian Antarctic Expedition (68th RAE) took part in the study. For two participants (1 and 2) this was the first expedition, for participant 3 it was the 5th. Testing of HRV indicators was carried out during the sea passage (two periods: 1 – initial, “cold”, and 2 – “warm”, in tropical waters), and in the first weeks of work on the ice continent (period 3 – preparation and disembarkation, period 4 – routine work on the mainland). We used the BioMouse software and hardware complex, model KFP-01b (NeuroLab LLC, Russian Federation), and the method of variation pulsometry. The duration of each recording was 90–120 s. Statistical, geometric and spectral indicators of HRV were analyzed by period, separately for each subject.
Results. According to the indicators recognized as correlates of sympathetic influences on HRV, a decrease in the SDNN indicator from the 1st to the 2nd periods of the expedition (during the sea passage) and a tendency towards a decrease in the power of the LF band in participant 3 were found, as well as a tendency towards a decrease in the SDNN indicator during this period time interval for participant 1. The stress index increased from the first part of the journey to the period of preparation for disembarkation for participants 1 and 3, and did not change for participant 2. According to indicators recognized as correlates of vagal influences on HRV, a tendency to increase RMSSD was revealed in subject with code 3 after the start of routine work at the station; HF band power dynamics were multidirectional in participants 1 and 2 and absent in participant 3.
Conclusion. In general, the direction of the dynamics of HRV indicators during the Antarctic expedition has a clear sanogenetic orientation, and reflects the presence of an acute adaptive phase at the beginning of the sea transition in the form of activation of sympathetic influences; increased stress index when landing on the mainland; and the possible increase in vagal influences during routine work at the base in Antarctica. The features of the shifts are specific depending on the experience of the expedition participants. In conditions of expeditions, where it is difficult to carry out the 5-minute HRV recordings recommended by professional communities and one has to limit oneself to shorter recordings, statistical indicators are more informative and reliable.
