Document Detail


Reduced leg blood flow during dynamic exercise in older endurance-trained men.
MedLine Citation:
PMID:  9655757     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
It is currently unclear whether aging alters the perfusion of active muscles during large-muscle dynamic exercise in humans. To study this issue, direct measurements of leg blood flow (femoral vein thermodilution) and systemic arterial pressure during submaximal cycle ergometry (70, 140, and 210 W) were compared between six younger (Y; 22-30 yr) and six older (O; 55-68 yr) chronically endurance-trained men. Whole body O2 uptake, ventilation, and arterial and femoral venous samples for blood-gas, catecholamine, and lactate determinations were also obtained. Training duration (min/day), estimated leg muscle mass (dual-energy X-ray absorptiometry; Y, 21.5 +/- 1.2 vs. O, 19.9 +/- 0.9 kg), and blood hemoglobin concentration (Y, 14.9 +/- 0.4 vs. O, 14.7 +/- 0.2 g/dl) did not significantly differ (P > 0.05) between groups. Leg blood flow, leg vascular conductance, and femoral venous O2 saturation were approximately 20-30% lower in the older men at each work rate (all P < 0.05), despite similar levels of whole body O2 uptake. At 210 W, leg norepinephrine spillover rates and femoral venous lactate concentrations were more than twofold higher in the older men. Pulmonary ventilation was also higher in the older men at 140 (+24%) and 210 (+39%) W. These results indicate that leg blood flow and vascular conductance during cycle ergometer exercise are significantly lower in older endurance-trained men in comparison to their younger counterparts. The mechanisms responsible for this phenomenon and the extent to which they operate in other groups of older subjects deserve further attention.
Authors:
D N Proctor; P H Shen; N M Dietz; T J Eickhoff; L A Lawler; E J Ebersold; D L Loeffler; M J Joyner
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Publication Detail:
Type:  Clinical Trial; Comparative Study; Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  85     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  1998 Jul 
Date Detail:
Created Date:  1998-08-17     Completed Date:  1998-08-17     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:  68-75     Citation Subset:  IM    
Affiliation:
Department of Anesthesiology and General Clinical Research Center, Mayo Clinic, Rochester, Minnesota 55905, USA. proctor.david@mayo.edu
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MeSH Terms
Descriptor/Qualifier:
Adult
Aged
Aging / physiology*
Blood Gas Analysis
Blood Pressure / physiology
Catecholamines / blood
Energy Metabolism / physiology
Exercise / physiology*
Exercise Test
Humans
Lactic Acid / blood
Leg / blood supply*
Male
Middle Aged
Oxygen Consumption / physiology
Physical Endurance / physiology*
Physical Fitness / physiology*
Regional Blood Flow / physiology*
Grant Support
ID/Acronym/Agency:
HL-46493/HL/NHLBI NIH HHS; NS-32352/NS/NINDS NIH HHS; RR-00585-25/RR/NCRR NIH HHS
Chemical
Reg. No./Substance:
0/Catecholamines; 50-21-5/Lactic Acid

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


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