Document Detail

Acceleration of VO2 kinetics in heavy submaximal exercise by hyperoxia and prior high-intensity exercise.
MedLine Citation:
PMID:  9338442     Owner:  NLM     Status:  MEDLINE    
We examined the hypothesis that O2 uptake (VO2) would change more rapidly at the onset of step work rate transitions in exercise with hyperoxic gas breathing and after prior high-intensity exercise. The kinetics of VO2 were determined from the mean response time (MRT; time to 63% of total change in VO2) and calculations of O2 deficit and slow component during normoxic and hyperoxic gas breathing in one group of seven subjects during exercise below and above ventilatory threshold (VT) and in another group of seven subjects during exercise above VT with and without prior high-intensity exercise. In exercise transitions below VT, hyperoxic gas breathing did not affect the kinetic response of VO2 at the onset or end of exercise. At work rates above VT, hyperoxic gas breathing accelerated both the on- and off-transient MRT, reduced the O2 deficit, and decreased the VO2 slow component from minute 3 to minute 6 of exercise, compared with normoxia. Prior exercise above VT accelerated the on-transient MRT and reduced the VO2 slow component from minute 3 to minute 6 of exercise in a second bout of exercise with both normoxic and hyperoxic gas breathing. However, the summated O2 deficit in the second normoxic and hyperoxic steps was not different from that of the first steps in the same gas condition. Faster on-transient responses in exercise above, but not below, VT with hyperoxia and, to a lesser degree, after prior high-intensity exercise above VT support the theory of an O2 transport limitation at the onset of exercise for workloads >VT.
M Macdonald; P K Pedersen; R L Hughson
Publication Detail:
Type:  Clinical Trial; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  83     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  1997 Oct 
Date Detail:
Created Date:  1997-11-26     Completed Date:  1997-11-26     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:  1318-25     Citation Subset:  IM; S    
Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1.
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MeSH Terms
Anaerobic Threshold / physiology
Exercise / physiology*
Models, Biological
Muscle, Skeletal / metabolism,  physiology
Oxygen / administration & dosage,  pharmacology*
Oxygen Consumption / physiology*
Pulmonary Gas Exchange / physiology
Respiratory Mechanics / drug effects,  physiology
Reg. No./Substance:

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