Respiratory physiology & neurobiology · 2025
The change in phase shift between respiratory oscillations of mean arterial pressure and heart rate in head-up tilt test: The effect of simulated microgravity.
СтатьяПоддержка исследования: вне правительства СШАНазвание и аннотация: Перевод в очереди
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Borovik Anatoly S, Zhedyaev Roman Yu, Negulyaev Vladimir O, Bogotskoy Kirill A, Iashina Viktoriia A, Tomilovskaya Elena S, Tarasova Olga S, Vinogradova Olga L
Аннотация
PURPOSE: We studied the synchronization of mean arterial pressure (MAP) and heart rate (HR) high frequency (HF) respiratory oscillations in young men in the supine position and during head-up tilt (HUT), and then analyzed the effect of blood redistribution on these parameters in the lower body negative pressure (LBNP) test, sit-to-stand test and HUT test performed after a 7-day dry immersion (DI, on-ground model of microgravity).
METHODS: 75 young male volunteers participated in the study. Blood pressure and ECG were continuously recorded, to obtain mean arterial pressure (MAP), heart rate (HR) and wavelet spectra of these parameters. Phases of the oscillations were calculated using Morse analytical wavelets. The synchronization between oscillations was estimated using phase synchronization index (PSI) calculated from Shannon entropy for phase difference distribution histogram.
RESULTS: HUT increased the amplitude of HF MAP waves, but decreased the amplitude of HF waves of HR. The phase shift between HF MAP and HR waves decreased, but the degree of their synchronization increased, as reflected by an increase in the HF peak in PSI spectrum. Similar changes, except for an increase in PSI, were recorded upon exposure to LBNP and in the sit-to-stand test. After 7-day exposure to DI conditions, phase shift between HF MAP and HR oscillations decreased in supine position and then did not change during orthostasis.
CONCLUSION: The changes in body position, LBNP and dry immersion exposure, which are associated with a decrease in vagal activity, affect the phase relationship between respiratory MAP and HR waves.
METHODS: 75 young male volunteers participated in the study. Blood pressure and ECG were continuously recorded, to obtain mean arterial pressure (MAP), heart rate (HR) and wavelet spectra of these parameters. Phases of the oscillations were calculated using Morse analytical wavelets. The synchronization between oscillations was estimated using phase synchronization index (PSI) calculated from Shannon entropy for phase difference distribution histogram.
RESULTS: HUT increased the amplitude of HF MAP waves, but decreased the amplitude of HF waves of HR. The phase shift between HF MAP and HR waves decreased, but the degree of their synchronization increased, as reflected by an increase in the HF peak in PSI spectrum. Similar changes, except for an increase in PSI, were recorded upon exposure to LBNP and in the sit-to-stand test. After 7-day exposure to DI conditions, phase shift between HF MAP and HR oscillations decreased in supine position and then did not change during orthostasis.
CONCLUSION: The changes in body position, LBNP and dry immersion exposure, which are associated with a decrease in vagal activity, affect the phase relationship between respiratory MAP and HR waves.