Document Detail

Oxygen transport during exercise at extreme altitude: Operation Everest II.
MedLine Citation:
PMID:  3115154     Owner:  NLM     Status:  MEDLINE    
Eight male volunteers had rest and exercise measurement to determine the mechanisms of oxygen transport during a 40-day chamber decompression simulating high-altitude exposure equivalent to the summit of Mt Everest. Five subjects completing the study decreased their maximum oxygen uptake by 72%. During maximal or near-maximal exercise, arterial PCO2 fell as low as 8 mm Hg, defending the alveolar PO2 and confirming marked hyperventilation. Alveolar-arterial diffusion did not improve and V/Q worsened. Cardiac function was unimpaired. Circulatory oxygen transport resembled that at sea level. The decrease in mixed venous PO2 was not enough to preserve fractional oxygen utilization "on the summit." The PO2 gradients from atmosphere to alveolus, alveolus to arterial blood, arterial to venous blood, and from venous (capillary) blood to mitochondria all decreased. However, hyperventilation appeared to be the primary adaptation that defended the maximum oxygen uptake.
J T Reeves; B M Groves; J R Sutton; P D Wagner; A Cymerman; M K Malconian; P B Rock; P M Young; J K Alexander; C S Houston
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Annals of emergency medicine     Volume:  16     ISSN:  0196-0644     ISO Abbreviation:  Ann Emerg Med     Publication Date:  1987 Sep 
Date Detail:
Created Date:  1987-10-01     Completed Date:  1987-10-01     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  8002646     Medline TA:  Ann Emerg Med     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  993-8     Citation Subset:  AIM; IM; S    
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MeSH Terms
Atmospheric Pressure
Biological Transport
Carbon Dioxide / blood
Heart Catheterization
Oxygen / blood*
Partial Pressure
Physical Exertion*
Grant Support
Reg. No./Substance:
124-38-9/Carbon Dioxide; 7782-44-7/Oxygen

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

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