Document Detail


Oxygen transport to exercising leg in chronic hypoxia.
MedLine Citation:
PMID:  3215859     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Residence at high altitude could be accompanied by adaptations that alter the mechanisms of O2 delivery to exercising muscle. Seven sea level resident males, aged 22 +/- 1 yr, performed moderate to near-maximal steady-state cycle exercise at sea level in normoxia [inspired PO2 (PIO2) 150 Torr] and acute hypobaric hypoxia (barometric pressure, 445 Torr; PIO2, 83 Torr), and after 18 days' residence on Pikes Peak (4,300 m) while breathing ambient air (PIO2, 86 Torr) and air similar to that at sea level (35% O2, PIO2, 144 Torr). In both hypoxia and normoxia, after acclimatization the femoral arterial-iliac venous O2 content difference, hemoglobin concentration, and arterial O2 content, were higher than before acclimatization, but the venous PO2 (PVO2) was unchanged. Thermodilution leg blood flow was lower but calculated arterial O2 delivery and leg VO2 similar in hypoxia after vs. before acclimatization. Mean arterial pressure (MAP) and total peripheral resistance in hypoxia were greater after, than before, acclimatization. We concluded that acclimatization did not increase O2 delivery but rather maintained delivery via increased arterial oxygenation and decreased leg blood flow. The maintenance of PVO2 and the higher MAP after acclimatization suggested matching of O2 delivery to tissue O2 demands, with vasoconstriction possibly contributing to the decreased flow.
Authors:
P R Bender; B M Groves; R E McCullough; R G McCullough; S Y Huang; A J Hamilton; P D Wagner; A Cymerman; J T Reeves
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  65     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  1988 Dec 
Date Detail:
Created Date:  1989-03-09     Completed Date:  1989-03-09     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:  2592-7     Citation Subset:  IM; S    
Affiliation:
Cardiovascular Pulmonary Research Laboratory, University of Colorado Health Sciences Center, Denver, 80262.
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MeSH Terms
Descriptor/Qualifier:
Acclimatization
Adult
Anoxia / blood*
Biological Transport, Active
Blood Flow Velocity
Humans
Leg / blood supply
Male
Oxygen / blood*
Oxygen Consumption
Physical Exertion*
Grant Support
ID/Acronym/Agency:
HL-14985/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
7782-44-7/Oxygen

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


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