Document Detail

Cardiovascular responses to exhaustive upright cycle exercise in highly trained older men.
MedLine Citation:
PMID:  7836158     Owner:  NLM     Status:  MEDLINE    
It is unclear whether the markedly enhanced aerobic exercise capacity of older endurance-trained men relative to their sedentary age peers is mediated primarily by central or peripheral cardiovascular mechanisms. To address this question, we performed radionuclide ventriculography with respiratory gas exchange measurements during exhaustive upright cycle ergometry in 16 endurance-trained men aged 63 +/- 7 yr and in 35 untrained men of similar age. As expected, maximal O2 consumption during treadmill exercise was much higher in athletes than in controls. At rest and during fixed submaximal cycle work rates through 100 W, athletes demonstrated lower heart rates and greater stroke volume indexes than controls while maintaining similar cardiac indexes and O2 uptake (VO2). At exhaustion, athletes achieved 53% higher work rates and peak VO2 per kilogram body weight than the sedentary men. The higher peak VO2 in athletes was achieved by a 22.5% larger cardiac index and a 15.6% greater arteriovenous O2 difference. The larger peak cardiac index in the athletes than in sedentary controls was mediated entirely by a greater stroke volume index; peak heart rates were virtually identical. The athletes' greater stroke volume index was achieved through an 11% larger end-diastolic volume index and a 7% higher ejection fraction, both of borderline significance. At exhaustion, athletes demonstrated a lower systemic vascular resistance than controls, despite a higher value at rest. Athletes also showed greater exercise-induced increments in heart rate, stroke volume index, and cardiac index and a greater reduction in systemic vascular resistance from rest to maximal workload.(ABSTRACT TRUNCATED AT 250 WORDS)
J L Fleg; S P Schulman; F C O'Connor; G Gerstenblith; L C Becker; S Fortney; A P Goldberg; E G Lakatta
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Publication Detail:
Type:  Clinical Trial; Comparative Study; Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  77     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  1994 Sep 
Date Detail:
Created Date:  1995-02-28     Completed Date:  1995-02-28     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:  1500-6     Citation Subset:  IM; S    
Department of Environmental Physiology, Johns Hopkins Medical Institutions, Baltimore, Maryland.
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MeSH Terms
Adaptation, Physiological
Cardiac Output
Cardiovascular Physiological Phenomena*
Exercise Test
Heart / physiology,  radionuclide imaging
Middle Aged
Oxygen Consumption
Physical Endurance / physiology
Physical Exertion / physiology*
Pulmonary Gas Exchange / physiology
Radionuclide Ventriculography
Ventricular Function, Left / physiology
Grant Support
N01-AG-4-2109/AG/NIA NIH HHS; P01-AG-04402-9/AG/NIA NIH HHS; R01-AG-07660/AG/NIA NIH HHS

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