Anton Cherepov
Federal Research Clinical Center, Russia
Title: Possible mechanisms of peripheral blood pressure adaptation to simulated chronic hypogravity
Biography
Biography: Anton Cherepov
Abstract
Human adaptation to extreme conditions primarily involves the basic vital systems of the body. The aim of our study was to analyze the mechanisms of adaptation of the cardiovascular system to simulated conditions of space flight and stay on the lunar surface.
Hypo- and microgravity was simulated using orthostatic and antiorthostatic hypokinesia, respectively (bedrest at different angles: -6° and +9.6°) and was carried out on volunteers in hospital setting.
Analysis of blood pressure variability (BPV) revealed significant increase in the systolic BPV by 8 day in head-down bedrest group (HDBRG) and return of these parameters to baseline values by day 21. Analysis of the frequency components of systolic BPV spectrum in HDBRG showed that the main contribution to the total spectral power on day 8 was made by the very-low-frequency component. At the same term, we observed a pronounced increase in the very-low-frequency component of heart rate variability (HRV) in HDBRG in comparison with that in head-up bedrest group (HUBRG). Coincidence of these changes may indicate that significant contribution into adaptation is made by central neural mechanisms that are activated during the first week of simulated microgravity. The diastolic BPV was markedly changes by day 21 in both experimental groups in comparison with baseline values, primarily at the expense of very-low-frequency component of BPV. In HRV, no similar changes were observed by day 21 of the experiment. These findings probably attest to predominance of local mechanisms of vascular tone regulation not directly related with the autonomic control.