ИСТИНА

Abstract The aim of this study is to evaluate the combined effects of a lunar bed rest analog and altered magnetic field, on cardiovascular system of healthy volunteers by means of the prerecorded magnetic storm exposure. Materials and methods. Eight healthy volunteers (26,1 ± 5,5 yr.) were enrolled in the blind study after previous examination of their health. The body mass index was 23.9 ± 3.9 kg / m2. Blood pressure and pulse at rest were within the normal range. Subjects did not take any medications, as well as coffee or caffeine-containing beverages. Each person has been exposed twice: under magnetic storm condition and, for comparison, in quiet magnetic conditions. During experiments, we did not provide for participants the information about the type of exposure to avoid possible influence of this information on the results of study. All volunteers gave the informed consent to take part in the experiment approved by the Committee on Biomedical Ethics. The experimental facility for magnetic field exposure named “Faraday” allow providing different types of magnetic fields exposure for a couple of days. The bed for subjects located in the center of a cubic construction (2.5 x 2.5 x 2.5m) so that to obtain maximum homogenous magnetic field during exposure. During the entire experiment, the subjects stay in the lying position. To simulate a lunar loading environment, the plane of the working surface of the bed was set at an angle of 9.6 degrees to the horizontal. Before experiments beginning the geomagnetic storm (GS) has been recorded (k-index=7) by 3-axis fluxgate magnetic field sensor (FL3-100, Stefan Mayer Instruments). Physiological studies included only noninvasive techniques. Heart rhythm and heart rate (HR) were recorded using the monitoring system “Astrocard” (Russia) which allows a simultaneous viewing of the ECG on the screen of a mobile device and storing the results obtained in the study. Each of the volunteers carried out loading veloergometry tests before the beginning of the experimental conditions and the morning of the next day after their termination. Results and conclusion. Veloergometry tests showed a decrease in the working capacity of the subjects relative to the initial value after being in a magnetic storm condition, compared with quiet magnetic conditions. The analysis of heart rate variability revealed a significant decrease in the duration of cardio intervals during the entire study when exposed in a magnetic storm compared to the conditions of a quiet magnetic condition. During magnetic storm exposure, 24-hour ECG monitoring revealed in one volunteer episodes of cardiac arrhythmias (supraventricular and ventricular extrasystoles). Second-degree atrioventricular bloc (2 episodes) was found at 24-hour ECG monitoring in other individual during magnetic storm condition.