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Human cutaneous vascular responses to whole-body tilting, Gz centrifugation, and LBNPWe hypothesized that gravitational stimuli elicit cardiovascular responses in the following order with gravitational stress equalized at the level of the feet, from lowest to highest response: short-(SAC) and long-arm centrifugation (LAC), tilt, and lower body negative pressure (LBNP). Up to 15 healthy subjects underwent graded application of the four stimuli. Laser-Doppler flowmetry measured regional skin blood flow. At 0.6 G(z) (60 mmHg LBNP), tilt and LBNP similarly reduced leg skin blood flow to approximately 36% of supine baseline levels. Flow increased back toward baseline levels at 80-100 mmHg LBNP yet remained stable during 0.8-1.0 G(z) tilt. Centrifugation usually produced less leg vasoconstriction than tilt or LBNP. Surprisingly, SAC and LAC did not differ significantly. Thigh responses were less definitive than leg responses. No gravitational vasoconstriction occurred in the neck. All conditions except SAC increased heart rate, according to our hypothesized order. LBNP may be a more effective and practical means of simulating cardiovascular effects of gravity than centrifugation.
Document ID
20050154917
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Watenpaugh, Donald E.
(NASA Ames Research Center Moffett Field, CA United States)
Breit, Gregory A.
Buckley, Theresa M.
Ballard, Richard E.
Murthy, Gita
Hargens, Alan R.
Date Acquired
August 23, 2013
Publication Date
June 1, 2004
Publication Information
Publication: Journal of applied physiology (Bethesda, Md. : 1985)
Volume: 96
Issue: 6
ISSN: 8750-7587
Subject Category
Aerospace Medicine
Distribution Limits
Public
Copyright
Other

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