| The lactate paradox revisited in lowlanders during acclimatization to 4100 m and in high-altitude natives. | |
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MedLine Citation:
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PMID: 19139048 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Chronic hypoxia has been proposed to induce a closer coupling in human skeletal muscle between ATP utilization and production in both lowlanders (LN) acclimatizing to high altitude and high-altitude natives (HAN), linked with an improved match between pyruvate availability and its use in mitochondrial respiration. This should result in less lactate being formed during exercise in spite of the hypoxaemia. To test this hypothesis six LN (22-31 years old) were studied during 15 min warm up followed by an incremental bicycle exercise to exhaustion at sea level, during acute hypoxia and after 2 and 8 weeks at 4100 m above sea level (El Alto, Bolivia). In addition, eight HAN (26-37 years old) were studied with a similar exercise protocol at altitude. The leg net lactate release, and the arterial and muscle lactate concentrations were elevated during the exercise in LN in acute hypoxia and remained at this higher level during the acclimatization period. HAN had similar high values; however, at the moment of exhaustion their muscle lactate, ADP and IMP content and Cr/PCr ratio were higher than in LN. In conclusion, sea-level residents in the course of acclimatization to high altitude did not exhibit a reduced capacity for the active muscle to produce lactate. Thus, the lactate paradox concept could not be demonstrated. High-altitude natives from the Andes actually exhibit a higher anaerobic energy production than lowlanders after 8 weeks of acclimatization reflected by an increased muscle lactate accumulation and enhanced adenine nucleotide breakdown. |
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Authors:
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G van Hall; C Lundby; M Araoz; J A L Calbet; M Sander; B Saltin |
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Publication Detail:
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Type: Comparative Study; Journal Article; Research Support, Non-U.S. Gov't Date: 2009-01-12 |
Journal Detail:
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Title: The Journal of physiology Volume: 587 ISSN: 1469-7793 ISO Abbreviation: J. Physiol. (Lond.) Publication Date: 2009 Mar |
Date Detail:
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Created Date: 2009-03-02 Completed Date: 2009-12-07 Revised Date: 2010-09-23 |
Medline Journal Info:
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Nlm Unique ID: 0266262 Medline TA: J Physiol Country: England |
Other Details:
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Languages: eng Pagination: 1117-29 Citation Subset: IM |
Affiliation:
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The Copenhagen Muscle Research Centre, Rigshospitalet section 7652, 9 Blegdamsvej, DK-2100 Copenhagen Ø, Denmark. gvanhall@cmrc.dk |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Acclimatization
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physiology* Adult Altitude* Bolivia Exercise Test / methods Humans Lactic Acid / analysis, metabolism* Male Mountaineering / physiology* Muscle, Skeletal / physiology Oxygen Consumption / physiology Population Groups Young Adult |
| Chemical | |
Reg. No./Substance:
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50-21-5/Lactic Acid |
| Comments/Corrections | |
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