Document Detail

VO2 and heart rate kinetics in cycling: transitions from an elevated baseline.
MedLine Citation:
PMID:  11356769     Owner:  NLM     Status:  MEDLINE    
The purpose of this study was to examine oxygen consumption (VO2) and heart rate kinetics during moderate and repeated bouts of heavy square-wave cycling from an exercising baseline. Eight healthy, male volunteers performed square-wave bouts of leg ergometry above and below the gas exchange threshold separated by recovery cycling at 35% VO2 peak. VO2 and heart rate kinetics were modeled, after removal of phase I data by use of a biphasic on-kinetics and monoexponential off-kinetics model. Fingertip capillary blood was sampled 45 s before each transition for base excess, HCO and lactate concentration, and pH. Base excess and HCO concentration were significantly lower, whereas lactate concentration and pH were not different before the second bout. The results confirm earlier reports of a smaller mean response time in the second heavy bout. This was the result of a significantly greater fast-component amplitude and smaller slow-component amplitude with invariant fast-component time constant. A role for local oxygen delivery limitation in heavy exercise transitions with unloaded but not moderate baselines is presented.
S E Bearden; R J Moffatt
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Publication Detail:
Type:  Clinical Trial; Journal Article    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  90     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2001 Jun 
Date Detail:
Created Date:  2001-05-17     Completed Date:  2001-07-26     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:  2081-7     Citation Subset:  IM    
Exercise Physiology Laboratory, Department of Nutrition, Food and Exercise Sciences, Florida State University, Tallahassee Florida 32306, USA.
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MeSH Terms
Bicycling / physiology*
Cardiac Output / physiology
Heart Rate / physiology*
Models, Biological
Oxygen Consumption / physiology*
Parasympathetic Nervous System / physiology
Pulmonary Gas Exchange / physiology
Regional Blood Flow / physiology
Stroke Volume / physiology
Sympathetic Nervous System / physiology

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

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