Document Detail


Induced hypervolemia, cardiac function, VO2max, and performance of elite cyclists.
MedLine Citation:
PMID:  10378906     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
OBJECTIVE: To determine whether plasma volume expansion (PVexp) in elite endurance-trained (ET) cyclists, who already possess both a high blood volume (BV) and a high VO2max, leads to further enhancements in their cardiac function, VO2max, and endurance performance (time to exhaustion at 95% VO2max). METHODS: Nine male ET cyclists (V02max = 68.9 +/- 0.6 (SEM) mL x kg(-1) x min(-1)) were studied employing a double blind, cross-over design; i) before PVexp, ii) after sham PVexp (Sham), iii) after restoration of normocythemia, iv) after PVexp (6% dextran), and v) upon reestablishment of normocythemia. RESULTS: PVexp resulted in a 547 +/- 61 mL increase in BV (P < 0.05). Maximal cardiac output and maximal stroke volume were higher (P < 0.05) after PVexp, but the magnitude of these increases was only sufficient to counter the hemodilution effect (lowered O2 content) of PVexp, such that O2 transport, VO2max, and endurance performance remained unchanged. CONCLUSIONS: Expansion of BV in elite ET cyclists, who already possess a high BV, does not improve their VO2max and endurance performance. Elite ET athletes may already be at an optimal BV, which is at or near the limits of their diastolic reserve capacity.
Authors:
D E Warburton; N Gledhill; V K Jamnik; B Krip; N Card
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Publication Detail:
Type:  Clinical Trial; Controlled Clinical Trial; Journal Article    
Journal Detail:
Title:  Medicine and science in sports and exercise     Volume:  31     ISSN:  0195-9131     ISO Abbreviation:  Med Sci Sports Exerc     Publication Date:  1999 Jun 
Date Detail:
Created Date:  1999-08-30     Completed Date:  1999-08-30     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  8005433     Medline TA:  Med Sci Sports Exerc     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  800-8     Citation Subset:  IM; S    
Affiliation:
Kinesiology and Health Science, York University, North York, Ontario, Canada.
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MeSH Terms
Descriptor/Qualifier:
Adult
Bicycling / physiology*
Blood Volume / physiology*
Cardiac Output / physiology*
Cardiovascular Physiological Phenomena
Humans
Male
Oxygen Consumption / physiology*
Physical Endurance / physiology*
Stroke Volume

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


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