Document Detail


Low blood flow at onset of moderate-intensity exercise does not limit muscle oxygen uptake.
MedLine Citation:
PMID:  20089709     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The effect of low blood flow at onset of moderate-intensity exercise on the rate of rise in muscle oxygen uptake was examined. Seven male subjects performed a 3.5-min one-legged knee-extensor exercise bout (24 +/- 1 W, mean +/- SD) without (Con) and with (double blockade; DB) arterial infusion of inhibitors of nitric oxide synthase (N(G)-monomethyl-l-arginine) and cyclooxygenase (indomethacin) to inhibit the synthesis of nitric oxide and prostanoids, respectively. Leg blood flow and leg oxygen delivery throughout exercise was 25-50% lower (P < 0.05) in DB compared with Con. Leg oxygen extraction (arteriovenous O(2) difference) was higher (P < 0.05) in DB than in Con (5 s: 127 +/- 3 vs. 56 +/- 4 ml/l), and leg oxygen uptake was not different between Con and DB during exercise. The difference between leg oxygen delivery and leg oxygen uptake was smaller (P < 0.05) during exercise in DB than in Con (5 s: 59 +/- 12 vs. 262 +/- 39 ml/min). The present data demonstrate that muscle blood flow and oxygen delivery can be markedly reduced without affecting muscle oxygen uptake in the initial phase of moderate-intensity exercise, suggesting that blood flow does not limit muscle oxygen uptake at the onset of exercise. Additionally, prostanoids and/or nitric oxide appear to play important roles in elevating skeletal muscle blood flow in the initial phase of exercise.
Authors:
Michael Nyberg; Stefan P Mortensen; Bengt Saltin; Ylva Hellsten; Jens Bangsbo
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Publication Detail:
Type:  Clinical Trial; Journal Article; Research Support, Non-U.S. Gov't     Date:  2010-01-20
Journal Detail:
Title:  American journal of physiology. Regulatory, integrative and comparative physiology     Volume:  298     ISSN:  1522-1490     ISO Abbreviation:  Am. J. Physiol. Regul. Integr. Comp. Physiol.     Publication Date:  2010 Mar 
Date Detail:
Created Date:  2010-03-01     Completed Date:  2010-03-30     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100901230     Medline TA:  Am J Physiol Regul Integr Comp Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  R843-8     Citation Subset:  IM    
Affiliation:
The Copenhagen Muscle Research Centre, Rigshospitalet, Copenhagen, Denmark.
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MeSH Terms
Descriptor/Qualifier:
Adult
Cyclooxygenase Inhibitors / administration & dosage
Drug Combinations
Enzyme Inhibitors / administration & dosage
Exercise / physiology*
Femoral Artery / physiology
Humans
Indomethacin / administration & dosage*
Leg / blood supply
Male
Muscle, Skeletal / physiology*
Nitric Oxide / metabolism
Nitroarginine / administration & dosage*
Oxygen Consumption / drug effects,  physiology*
Peroxides / blood
Prostaglandins / metabolism
Regional Blood Flow / drug effects,  physiology*
Urea / analogs & derivatives,  blood
Young Adult
Chemical
Reg. No./Substance:
0/Cyclooxygenase Inhibitors; 0/Drug Combinations; 0/Enzyme Inhibitors; 0/Peroxides; 0/Prostaglandins; 10102-43-9/Nitric Oxide; 124-43-6/carbamide peroxide; 2149-70-4/Nitroarginine; 53-86-1/Indomethacin; 57-13-6/Urea

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


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