ИСТИНА

Introduction. To solve the promising problems of space physiology and medicine, studies that simulate the long-term impact of hypomagnetic conditions (HMC) on the activity of the physiological systems of the body, including the cardiorespiratory and autonomic nervous systems, are relevant, since hypomagnetic conditions will occur during interplanetary flights or when people are on the Moon. The long-term effect of HMC on the body of practically healthy people remains poorly studied. In the available sources, we could not find data on changes in the parameters of central hemodynamics (heart rate (HR), blood pressure (BP)) and the autonomic Kerdo index (AKI) under the long-term effect of the HMC factor. The aim of the study: to search for patterns in changes in central hemodynamic parameters: heart rate, blood pressure (for each cardiac cycle), AKI and blood oxygenation in artificially created HMC. Material and methods of research. In experimental hypomagnetic conditions, the study of hemodynamics was carried out in 8 practically healthy men who were at rest and in a sitting position. HMC were created on a hypomagnetic stand using the «Arfa» device (result of intellectual activity No. 684-871-913 of 09.09.2019), which reduces the magnetic field induction by more than 800 times, the magnetic field induction inside the device when simulating the HMC was 0.044±0.008 µT, while without the HMC, the magnetic field induction inside the chamber was 44.32 ± 0.32 µT. ECG, heart rate, blood pressure, and SpO2 were monitored using an autonomous portable device SOMNOtouch NIBP (SomnoMedics, Germany), followed by the calculation of the AKI for each cardiac cycle, for 8 hours in two series of observations - under the action of the Earth’s natural magnetic field and with HMC. Results. After a comparative analysis of the measurement results, significant changes in hemodynamic parameters in the HMC have obtained in comparison with the control studies. The heart rate in most cases decreased by an average of 4 beats per minute. Blood pressure in the vast majority of cases significantly decreased: diastolic blood pressure (DBP) – on average by 11 mm Hg, systolic blood pressure (SBP) – on average by 16 mm Hg, which led to an increase in the AKI in the HMC, which increased by an average of 20 % (in 6 cases out of 8). The saturation of blood hemoglobin with oxygen under the influence of HMC have not changed. The polynomial models of the AKI during the time of exposure to HMC are found. Conclusion. For the first time, for a long time (within 8 hours), the effects of HMC on the regulation of the cardiovascular system in practically healthy volunteers who were in a state of wakefulness and relative rest in a sitting position have been researched. A physiological interpretation of the results is proposed: HMC at rest and in a sitting position in most cases have caused a significant decrease in the modulating effect of the parasympathetic autonomic nervous system on cardiovascular activity compared to control studies conducted under the same conditions, but without the HMC factor.