Document Detail

Evidence of cardiac functional reserve upon exhaustion during incremental exercise to determine VO2max.
MedLine Citation:
PMID:  23293009     Owner:  NLM     Status:  Publisher    
BACKGROUND: There remains considerable debate regarding the limiting factor(s) for maximal oxygen uptake (VO(2max)). Previous studies have shown that the central circulation may be the primary limiting factor for VO(2max) and that cardiac work increases beyond VO(2max). AIM: We sought to evaluate whether the work of the heart limits VO(2max) during upright incremental cycle exercise to exhaustion. METHODS: Eight trained men completed two incremental exercise trials, each terminating with exercise at two different rates of work eliciting VO(2max) (MAX and SUPRAMAX). During each exercise trial we continuously recorded cardiac output using pulse-contour analysis calibrated with a lithium dilution method. Intra-arterial pressure was recorded from the radial artery while pulmonary gas exchange was measured continuously for an assessment of oxygen uptake. RESULTS: The workload during SUPRAMAX (mean±SD: 346.5±43.2 W) was 10% greater than that achieved during MAX (315±39.3 W). There was no significant difference between MAX and SUPRAMAX for Q (28.7 vs 29.4 L/min) or VO(2) (4.3 vs 4.3 L/min). Mean arterial pressure was significantly higher during SUPRAMAX, corresponding to a higher cardiac power output (8.1 vs 8.5 W; p<0.06). CONCLUSIONS: Despite similar VO(2) and Q, the greater cardiac work during SUPRAMAX supports the view that the heart is working submaximally at exhaustion during an incremental exercise test (MAX).
Adrian D Elliott; Justin Skowno; Mahesh Prabhu; Timothy David Noakes; Les Ansley
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2013-1-4
Journal Detail:
Title:  British journal of sports medicine     Volume:  -     ISSN:  1473-0480     ISO Abbreviation:  Br J Sports Med     Publication Date:  2013 Jan 
Date Detail:
Created Date:  2013-1-7     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0432520     Medline TA:  Br J Sports Med     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
School of Life Sciences, Kingston University, Surrey, UK.
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