Document Detail

Effect of hypoxia and hyperoxia on human +Gz duration tolerance.
MedLine Citation:
PMID:  8045849     Owner:  NLM     Status:  MEDLINE    
To determine the effects of varying inspired O2 on positive radial acceleration (+Gz; i.e., head-to-foot inertial load) duration tolerance, seven men were exposed to the +4.5- to +7.0-Gz simulated aerial combat maneuver (SACM) by use of the Armstrong Laboratory (Brooks Air Force Base) centrifuge. Exposures were repeated on different days while subjects breathed gas mixtures of fractional concentration of O2 in inspired air (FIO2) between 0.12 and 0.6. SACM duration tolerance was positively related to inspired O2 of FIO2 between 0.12 and 0.2 but was unchanged at FIO2 between 0.2 and 0.6. SACM exposure decreased arterial O2 saturation and increased heart rates; SACM-induced changes were additive to FIO2 effects. The positive relationship between blood lactate and SACM duration tolerance at all FIO2 indicated an anaerobic component. It is concluded that SACM duration tolerance is limited by reduced FIO2 but not enhanced by hyperoxia. Thus the aerobic component of +4.5- to +7.0-Gz SACM duration tolerance is much greater than previously believed.
E L Besch; P M Werchan; J F Wiegman; T E Nesthus; A R Shahed
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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:  76     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  1994 Apr 
Date Detail:
Created Date:  1994-08-30     Completed Date:  1994-08-30     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:  1693-700     Citation Subset:  IM; S    
University of Florida, Gainesville 32610.
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MeSH Terms
Acceleration / adverse effects*
Anoxia / physiopathology*
Gravity Suits
Heart Rate / physiology
Lactates / blood
Lactic Acid
Oxygen / blood,  pharmacology*
Physical Education and Training
Reg. No./Substance:
0/Lactates; 50-21-5/Lactic Acid; 7782-44-7/Oxygen

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

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