| Respiratory muscle strength may explain hypoxia-induced decrease in vital capacity. | |
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MedLine Citation:
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PMID: 15870628 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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PURPOSE: High altitude exposure has consistently been reported to decrease forced vital capacity (FVC), but the mechanisms accounting for this observation remain incompletely understood. We investigated the possible contribution of a hypoxia-related decrease in respiratory muscle strength. METHODS: Maximal inspiratory and expiratory pressures (MIP and MEP), sniff nasal inspiratory pressure (SNIP), FVC, peak expiratory flow rate (PEF), and forced expiratory volume in 1 s (FEV1) were measured in 15 healthy subjects before and after 1, 6, and 12 h of exposure to an equivalent altitude of 4267 m in a hypobaric chamber. RESULTS: Hypoxia was associated with a progressive decrease in FVC (5.59 +/- 0.24 to 5.24 +/- 0.26 L, mean +/- SEM, P < 0.001), MIP (130 +/- 10 to 114 +/- 8 cm H2O, P < 0.01), MEP (201 +/- 12 to 171 +/- 11 cm H2O, P < 0.001), and SNIP (125 +/- 7 to 98 +/- 7 cm H2O, P < 0.001). MIP, MEP, and SNIP were strongly correlated to FVC (r ranging from 0.77 to 0.92). FEV1 didn't change, and PEF increased less than predicted by the reduction in air density (11-20% of sea-level value compared with 32% predicted). CONCLUSION: We conclude that a decrease in respiratory muscle strength may contribute to the decrease in FVC observed at high altitude. |
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Authors:
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Gaël Deboeck; Jean Jacques Moraine; Robert Naeije |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Medicine and science in sports and exercise Volume: 37 ISSN: 0195-9131 ISO Abbreviation: Med Sci Sports Exerc Publication Date: 2005 May |
Date Detail:
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Created Date: 2005-05-04 Completed Date: 2005-09-08 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 8005433 Medline TA: Med Sci Sports Exerc Country: United States |
Other Details:
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Languages: eng Pagination: 754-8 Citation Subset: IM; S |
Affiliation:
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Department of Physiology, Faculty of Medicine, Free University of Brussels, Belgium. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Adult Altitude Anoxia / physiopathology* Female Heart Rate / physiology Humans Male Middle Aged Respiratory Function Tests Respiratory Muscles / physiology* Vital Capacity / physiology* |
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