Document Detail

Effects of spaceflight on human calf hemodynamics.
MedLine Citation:
PMID:  11247959     Owner:  NLM     Status:  MEDLINE    
Chronic microgravity may modify adaptations of the leg circulation to gravitational pressures. We measured resting calf compliance and blood flow with venous occlusion plethysmography, and arterial blood pressure with sphygmomanometry, in seven subjects before, during, and after spaceflight. Calf vascular resistance equaled mean arterial pressure divided by calf flow. Compliance equaled the slope of the calf volume change and venous occlusion pressure relationship for thigh cuff pressures of 20, 40, 60, and 80 mmHg held for 1, 2, 3, and 4 min, respectively, with 1-min breaks between occlusions. Calf blood flow decreased 41% in microgravity (to 1.15 +/- 0.16 ml x 100 ml(-1) x min(-1)) relative to 1-G supine conditions (1.94 +/- 0.19 ml x 100 ml(-1) x min(-1), P = 0.01), and arterial pressure tended to increase (P = 0.05), such that calf vascular resistance doubled in microgravity (preflight: 43 +/- 4 units; in-flight: 83 +/- 13 units; P < 0.001) yet returned to preflight levels after flight. Calf compliance remained unchanged in microgravity but tended to increase during the first week postflight (P > 0.2). Calf vasoconstriction in microgravity qualitatively agrees with the "upright set-point" hypothesis: the circulation seeks conditions approximating upright posture on Earth. No calf hemodynamic result exhibited obvious mechanistic implications for postflight orthostatic intolerance.
D E Watenpaugh; J C Buckey; L D Lane; F A Gaffney; B D Levine; W E Moore; S J Wright; C G Blomqvist
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  90     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2001 Apr 
Date Detail:
Created Date:  2001-03-15     Completed Date:  2001-05-31     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1552-8     Citation Subset:  IM; S    
Department of Physiology, University of Texas Southwestern Medical Center, Dallas, Texas 75235, USA.
Space Flight Mission:
Flight Experiment; STS-40 Shuttle Project; STS-58 Shuttle Project; manned; short duration
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MeSH Terms
Blood Pressure / physiology
Heart Rate / physiology
Hemodynamics / physiology*
Leg / blood supply*
Middle Aged
Regional Blood Flow / physiology
Space Flight*
Supine Position / physiology
Vascular Resistance / physiology
C G Blomqvist / U TX SW Med Ctr, Dallas

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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