In anaesthetised cats, antiorthostatic posture of the body with an inclination angle of 30 degrees increased pressure in the vena cava superior and in jugular vein. The rest of the cardio-respiratory parameters were changed insignificantly. Physical and physiological mechanisms of the blood regional redistribution in alteration of the body gravitation orientation, are discussed.
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Clin Hemorheol Microcirc
May 2024
Department of Normal Physiology, Avicenna Tajik State Medical University, Dushanbe, Tajikistan.
Background: The impact of gravity on the existence of all living things has long been of interest to scientists. The force of the Earth's gravity combined with hypoxia significantly affects blood circulation and blood accumulation in various parts of the human and animal body. To date, the relationship between body position and blood circulation in pulmonary circulation under hypobaric hypoxia has not been sufficiently studied.
View Article and Find Full Text PDFJ Physiol Anthropol
April 2023
Department of Ecological Physiology, Federal State Budgetary Scientific Institution "Institute of Experimental Medicine", 12 Academic Pavlov St, Saint-Petersburg, 197022, Russia.
This review focuses on the effects of different body positions on intracranial fluid dynamics, including cerebral arterial and venous flow, cerebrospinal fluid (CSF) hydrodynamics, and intracranial pressure (ICP). It also discusses research methods used to quantify these effects. Specifically, the implications of three types of body positions (orthostatic, supine, and antiorthostatic) on cerebral blood flow, venous outflow, and CSF circulation are explored, with a particular emphasis on cerebrovascular autoregulation during microgravity and head-down tilt (HDT), as well as posture-dependent changes in cerebral venous and CSF flow, ICP, and intracranial compliance (ICC).
View Article and Find Full Text PDFBull Exp Biol Med
May 2020
Research Institute for Space Medicine, Federal Research Clinical Centre, Federal Medical-Biological Agency of Russia, Moscow, Russia.
The effects of anti-orthostatic hypokinesia on the parameters of vertical posture (orthostatic and postural stability) were studied. Anti-orthostatic hypokinesia was followed by orthostatic instability manifested in a decrease in the tolerance time in the orthostatic test, a significant increase in HR and systolic BP starting from the 11th minute of the test. Significant changes in the parameters reflecting postural stability were observed starting from minutes 10-11 of the stabilometric test.
View Article and Find Full Text PDFJ Altern Complement Med
August 2019
4Eastern Virginia Medical School, Norfolk, Eastern Virginia.
Most yoga practitioners believe that headstand (Sirshasana) results in increased cerebral perfusion. This, however, is not consistent with autoregulation of the cerebral blood flow. The intent of this study was to demonstrate the effect of Sirshasana on the blood flow to the brain through ultrasound examination of the internal carotid artery (ICA).
View Article and Find Full Text PDFBull Exp Biol Med
December 2018
Komi Research Center, Ural Division of the Russian Academy of Sciences, Syktyvkar, Russia.
We studied electrophysiological mechanisms of ventricular arrhythmias in dogs (n=7) under conditions of antiorthostatic hypokinesia (head-down tilt 45°). Abnormal transmural heterogeneity of repolarization in the base and apex of the left ventricle and increased dispersion of myocardial repolarization were revealed. By minute 30 of antiorthostatic hypokinesia, an increase in the duration of repolarization was revealed after a period of ventricular arrhythmia in all segments and regions of heart ventricles, which was accompanied by impairment of the pumping function of the heart.
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