| Exercise intolerance at high altitude (5050m): Critical power and W' | |
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MedLine Citation:
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PMID: 21621651 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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The relationship between work rate (WR) and its tolerable duration (t(LIM)) has not been investigated at high altitude (HA). At HA (5050m) and at sea level (SL), six subjects therefore performed symptom-limited cycle-ergometry: an incremental test (IET) and three constant-WR tests (% of IET WR(max), HA and SL respectively: WR(1) 70±8%, 74±7%; WR(2) 86±14%, 88±10%; WR(3) 105±13%, 104±9%). The power asymptote (CP) and curvature constant (W') of the hyperbolic WR-t(LIM) relationship were reduced at HA compared to SL (CP: 81±21 vs. 123±38W; W': 7.2±2.9 vs. 13.1±4.3kJ). HA breathing reserve (estimated maximum voluntary ventilation minus end-exercise ventilation) was also compromised (WR(1): 25±25 vs. 50±18lmin(-1); WR(2): 4±23 vs. 38±23lmin(-1); WR(3): -3±18 vs. 32±24lmin(-1)) with near-maximal dyspnea levels (Borg) (WR(1): 7.2±1.2 vs. 4.8±1.3; WR(2): 8.8±0.8 vs. 5.3±1.2; WR(3): 9.3±1.0 vs. 5.3±1.5). The CP reduction is consistent with a reduced O(2) availability; that of W' with reduced muscle-venous O(2) storage, exacerbated by ventilatory limitation and dyspnea. |
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Authors:
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G Valli; A Cogo; C Passino; D Bonardi; G Morici; V Fasano; M Agnesi; L Bernardi; A M Ferrazza; S A Ward; P Palange |
Publication Detail:
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Type: JOURNAL ARTICLE Date: 2011-5-19 |
Journal Detail:
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Title: Respiratory physiology & neurobiology Volume: - ISSN: 1878-1519 ISO Abbreviation: - Publication Date: 2011 May |
Date Detail:
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Created Date: 2011-5-30 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 101140022 Medline TA: Respir Physiol Neurobiol Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
Copyright Information:
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Copyright © 2011. Published by Elsevier B.V. |
Affiliation:
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Department of Clinical Medicine, University of Rome "La Sapienza", viale dell'università, 37-00185 Rome, Italy. |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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