| Acute altitude exposure and altered acid-base states. II. Effects on exercise performance and muscle and blood lactate. | |
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MedLine Citation:
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PMID: 3396558 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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This study examined the influence of the respiratory alkalosis of acute altitude (AL) exposure alone or in combination with metabolic acid-base manipulations on exercise performance and muscle and blood lactate accumulation. Four subjects exercised for 10 min at 50% and 75% and to exhaustion at 90% of ground level (GL) VO2max, and at the same relative exercise intensities during three exposures to a simulated altitude of 4200 m; (i) normal (NAL), (ii) following 0.2 g.kg-1 ingestion of sodium bicarbonate (BAL), and (iii) following 0.5 g.day-1 ingestion of acetazolamide for 2 days prior to exposure (AAL). Muscle and blood lactate values were similar throughout exercise for GL and NAL. Although muscle lactates were similar among AL conditions blood lactate was reduced for AAL and increased following exhaustive exercise for BAL compared with NAL. Time to exhaustion at 90% VO2max was increased for NAL (10.4 +/- 1.6 min) compared with GL (7.1 +/- 0.2 min). Performance time was decreased for AAL (6.3 +/- 2.8 min) compared with NAL and BAL (12.4 +/- 4.2 min). These data suggest that the induced respiratory alkalosis of acute AL exposure may enhance exercise performance at high relative intensities. In contrast, the ingestion of acetazolamide before AL exposure would have detrimental effects on performance. The mechanism responsible for these changes may relate to the possible influence of altered extracellular acid-base states on intracellular hydrogen ion accumulation and lactate release. |
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Authors:
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T McLellan; I Jacobs; W Lewis |
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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: European journal of applied physiology and occupational physiology Volume: 57 ISSN: 0301-5548 ISO Abbreviation: Eur J Appl Physiol Occup Physiol Publication Date: 1988 |
Date Detail:
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Created Date: 1988-08-30 Completed Date: 1988-08-30 Revised Date: 2008-11-21 |
Medline Journal Info:
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Nlm Unique ID: 0410266 Medline TA: Eur J Appl Physiol Occup Physiol Country: GERMANY, WEST |
Other Details:
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Languages: eng Pagination: 445-51 Citation Subset: IM; S |
Affiliation:
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Defence and Civil Institute of Environmental Medicine, Downsview, Ontario, Canada. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Acid-Base Equilibrium* Adult Altitude* Blood Gas Analysis Heart Rate Humans Lactates / blood, metabolism* Lactic Acid Male Muscles / metabolism* Oxygen Consumption Physical Endurance Physical Exertion* Time Factors |
| Chemical | |
Reg. No./Substance:
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0/Lactates; 50-21-5/Lactic Acid |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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