Document Detail


Similar carbohydrate but enhanced lactate utilization during exercise after 9 wk of acclimatization to 5,620 m.
MedLine Citation:
PMID:  12388157     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We hypothesized that reliance on lactate as a means of energy distribution is higher after a prolonged period of acclimatization (9 wk) than it is at sea level due to a higher lactate Ra and disposal from active skeletal muscle. To evaluate this hypothesis, six Danish lowlanders (25 +/- 2 yr) were studied at rest and during 20 min of bicycle exercise at 146 W at sea level (SL) and after 9 wk of acclimatization to 5,260 m (Alt). Whole body glucose Ra was similar at SL and Alt at rest and during exercise. Lactate Ra was also similar for the two conditions at rest; however, during exercise, lactate Ra was substantially lower at SL (65 micro mol. min(-1). kg body wt(-1)) than it was at Alt (150 micro mol. min(-1). kg body wt(-1)) at the same exercise intensity. During exercise, net lactate release was approximately 6-fold at Alt compared with SL, and related to this, tracer-calculated leg lactate uptake and release were both 3- or 4-fold higher at Alt compared with SL. The contribution of the two legs to glucose disposal was similar at SL and Alt; however, the contribution of the two legs to lactate Ra was significantly lower at rest and during exercise at SL (27 and 81%) than it was at Alt (45 and 123%). In conclusion, at rest and during exercise at the same absolute workload, CHO and blood glucose utilization were similar at SL and at Alt. Leg net lactate release was severalfold higher, and the contribution of leg lactate release to whole body lactate Ra was higher at Alt compared with SL. During exercise, the relative contribution of lactate oxidation to whole body CHO oxidation was substantially higher at Alt compared with SL as a result of increased uptake and subsequent oxidation of lactate by the active skeletal muscles.
Authors:
G Van Hall; J A L Calbet; H Sondergaard; B Saltin
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Publication Detail:
Type:  Clinical Trial; Journal Article; Research Support, Non-U.S. Gov't     Date:  2002-07-30
Journal Detail:
Title:  American journal of physiology. Endocrinology and metabolism     Volume:  283     ISSN:  0193-1849     ISO Abbreviation:  Am. J. Physiol. Endocrinol. Metab.     Publication Date:  2002 Dec 
Date Detail:
Created Date:  2002-11-08     Completed Date:  2002-12-09     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  100901226     Medline TA:  Am J Physiol Endocrinol Metab     Country:  United States    
Other Details:
Languages:  eng     Pagination:  E1203-13     Citation Subset:  IM; S    
Affiliation:
Copenhagen Muscle Research Centre, Rigshospitalet section 7652, DK-2100 Copenhagen Ø, Denmark. gvhall@cmrc.dk
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MeSH Terms
Descriptor/Qualifier:
Acclimatization / physiology*
Adult
Altitude*
Blood Glucose / metabolism
Bolivia
Carbohydrate Metabolism*
Carbon Dioxide / analysis,  metabolism
Carbon Isotopes
Denmark
Deuterium
Exercise Test
Female
Femoral Artery / physiology
Femoral Vein / physiology
Glucose / metabolism,  pharmacokinetics
Humans
Lactic Acid / metabolism*,  pharmacokinetics
Leg
Male
Muscle, Skeletal / blood supply,  metabolism
Oxidation-Reduction
Physical Exertion / physiology*
Pulmonary Gas Exchange
Chemical
Reg. No./Substance:
0/Blood Glucose; 0/Carbon Isotopes; 124-38-9/Carbon Dioxide; 50-21-5/Lactic Acid; 50-99-7/Glucose; 7782-39-0/Deuterium

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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