Document Detail


Control of oxygen uptake during exercise.
MedLine Citation:
PMID:  18379208     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Other than during sleep and contrived laboratory testing protocols, humans rarely exist in prolonged metabolic steady states; rather, they transition among different metabolic rates (V O2). The dynamic transition of V O2 (V O2 kinetics), initiated, for example, at exercise onset, provides a unique window into understanding metabolic control. This brief review presents the state-of-the art regarding control of V O2 kinetics within the context of a simple model that helps explain the work rate dependence of V O2 kinetics as well as the effects of environmental perturbations and disease. Insights emerging from application of novel approaches and technologies are integrated into established concepts to assess in what circumstances O2 supply might exert a commanding role over V O2 kinetics, and where it probably does not. The common presumption that capillary blood flow dynamics can be extrapolated accurately from upstream arterial measurements is challenged. From this challenge, new complexities emerge with respect to the relationships between O2 supply and flux across the capillary-myocyte interface and the marked dependence of these processes on muscle fiber type. Indeed, because of interfiber type differences in O2 supply relative to V O2, the presence of much lower O2 levels in the microcirculation supplying fast-twitch muscle fibers, and the demonstrated metabolic sensitivity of muscle to O2, it is possible that fiber type recruitment profiles (and changes thereof) might help explain the slowing of V O2 kinetics at higher work rates and in chronic diseases such as heart failure and diabetes.
Authors:
David C Poole; Thomas J Barstow; Paul McDonough; Andrew M Jones
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't; Review    
Journal Detail:
Title:  Medicine and science in sports and exercise     Volume:  40     ISSN:  0195-9131     ISO Abbreviation:  Med Sci Sports Exerc     Publication Date:  2008 Mar 
Date Detail:
Created Date:  2008-04-01     Completed Date:  2008-05-22     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8005433     Medline TA:  Med Sci Sports Exerc     Country:  United States    
Other Details:
Languages:  eng     Pagination:  462-74     Citation Subset:  IM; S    
Affiliation:
Department of Kinesiology, Anatomy and Physiology, Kansas State University, Manhattan, KS 66506-5802, USA. poole@vet.ksu.edu
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MeSH Terms
Descriptor/Qualifier:
Biomechanics
Exercise / physiology*
Humans
Microcirculation
Muscle, Skeletal / blood supply,  metabolism
Oxygen Consumption / physiology*
Grant Support
ID/Acronym/Agency:
HL-50306/HL/NHLBI NIH HHS

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