Key result
Exposure to head-to-legs g-loads (+Gz) on a short-arm centrifuge decreased femoral artery blood flow by 60% compared to rest, while medial cerebral artery blood flow decreased by no more than 10%.
Why the study?
The study was designed to use objective monitoring instruments to test whether hemodynamic reactions to +Gz on a short-arm centrifuge are analogous to reactions seen during tilt testing or lower body negative pressure.
Does exposure to head-to-legs g-loads (+Gz) on a short-arm centrifuge alter peripheral arterial blood flow in normal male subjects?
Does exposure to head-to-legs g-loads (+Gz) on a short-arm centrifuge alter peripheral arterial blood flow in normal male subjects?
Head-to-legs g-loads on a short-arm centrifuge produce typical anti-gravity hemodynamic changes, significantly decreasing femoral artery blood flow while preserving cerebral blood flow.
Small SAC study in healthy men leaves open whether +Gz hemodynamics mirror tilt or LBNP; validation trials needed before clinical use.
We investigated peripheral arterial blood flow during exposure to the head-to-legs g-loads (+Gz) on a short-arm centrifuge (SAC). Purpose was to use some objective monitoring instruments for testing the hypothesis that the hemodynamic reaction to +Gz would be analogous to the reactions observed in the tilt test and/or the lower body negative pressure (LBNP) test. Six normal male subjects participated in 6 SAC runs with alternating interval g-loads of +1.27 Gz and +2.7 Gz. Blood flow in the femoral (FA) and medial cerebral (MCA) arteries was recorded continuously before, during and after runs with the use of Doppler flowmetry (Kardiomed device). It was found that +Gz centrifugation produced typical anti-gravity changes in hemodynamics, i.e. an increase in FA resistance and decrease in MCR resistance. In comparison to the records at rest, FA blood flow decreased 60 %; MCA blood flow changed insignificantly - no more than 10 % down. It was borne out that +Gz centrifugation has same effects as the Earth's gravity in standing humans, produces orthostatic blood pressure in the lower part of the body, and initiates the totality of anti-gravity hemodynamic reactions. Doppler recording was a quite useful source of data about the blood flow reaction to +Gz centrifugation.
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Fomina et al. (2023) studied Healthy (n=6). Head-to-legs g-loads (+Gz) on a short-arm centrifuge vs. Rest was evaluated on Blood flow in the femoral (FA) and medial cerebral (MCA) arteries. Exposure to head-to-legs g-loads (+Gz) on a short-arm centrifuge decreased femoral artery blood flow by 60% compared to rest, while medial cerebral artery blood flow decreased by no more than 10%.
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