| Intermittent altitude exposures improve muscular performance at 4,300 m. | |
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MedLine Citation:
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PMID: 12819214 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Chronic altitude residence improves muscular performance at altitude, but the effect of intermittent altitude exposures (IAE) on muscular performance at altitude has not been defined. The purpose of this study was to determine the effects of 3 wk of IAE, in combination with rest and cycle training, on muscular performance at altitude. Six lowlanders (23 +/- 2 yr, 77 +/- 6 kg; means +/- SE) completed a cycle time trial and adductor pollicis endurance test at sea level and during a 30-h acute exposure to 4,300 m altitude equivalent (barometric pressure = 446 mmHg) once before (pre-IAE) and once after (post-IAE) a 3-wk period of IAE (4 h/day, 5 days/wk, 4,300 m). During each IAE, three subjects cycled for 45-60 min/day at 60%-70% of maximal O2 uptake and three subjects rested. Cycle training during each IAE did not appear to affect muscular performance at altitude. Thus data from all six subjects were combined. Three weeks of IAE resulted in 1) a 21 +/- 6% improvement (P < 0.05) in cycle time-trial performance (min) from pre-IAE (32.8 +/- 3.7) to post-IAE (24.8 +/- 1.2), 2) a 63 +/- 26% improvement (P < 0.05) in adductor pollicis endurance (min) from pre-IAE (9.2 +/- 2.8) to post-IAE (14.8 +/- 4.2), and 3) a 10 +/- 4% increase (P < 0.05) in resting arterial O2 saturation (%) from pre-IAE (82 +/- 2) to post-IAE (90 +/- 1). These improvements in muscular performance after IAE correlated strongly with increases in resting arterial O2 saturation and were comparable to those reported previously after chronic altitude residence. IAE may therefore be used as an alternative to chronic altitude residence to facilitate improvements in muscular performance in athletes, soldiers, mountaineers, shift workers, and others that are deployed to altitude. |
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Authors:
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Beth A Beidleman; Stephen R Muza; Charles S Fulco; Allen Cymerman; Dan T Ditzler; Dean Stulz; Janet E Staab; Scott R Robinson; Gary S Skrinar; Steven F Lewis; Michael N Sawka |
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Publication Detail:
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Type: Journal Article Date: 2003-06-20 |
Journal Detail:
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Title: Journal of applied physiology (Bethesda, Md. : 1985) Volume: 95 ISSN: 8750-7587 ISO Abbreviation: J. Appl. Physiol. Publication Date: 2003 Nov |
Date Detail:
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Created Date: 2003-10-13 Completed Date: 2004-06-15 Revised Date: 2004-11-17 |
Medline Journal Info:
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Nlm Unique ID: 8502536 Medline TA: J Appl Physiol Country: United States |
Other Details:
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Languages: eng Pagination: 1824-32 Citation Subset: IM |
Affiliation:
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Biophysics and Biomedical Modeling Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts 01760, USA. beth.beidleman@na.amedd.army.mil |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Adaptation, Physiological
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physiology* Adult Altitude* Anoxia / physiopathology* Atmosphere Exposure Chambers* Atmospheric Pressure Bicycling / physiology Female Humans Male Mountaineering / physiology Muscle Contraction / physiology Muscle, Skeletal / physiology* Oxygen Consumption / physiology Physical Endurance / physiology |
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