Document Detail

Skeletal muscle metabolism and work capacity: a 31P-NMR study of Andean natives and lowlanders.
MedLine Citation:
PMID:  1864776     Owner:  NLM     Status:  MEDLINE    
Two metabolic features of altitude-adapted humans are the maximal O2 consumption (VO2max) paradox (higher work rates following acclimatization without increases in VO2max) and the lactate paradox (progressive reductions in muscle and blood lactate with exercise at increasing altitude). To assess underlying mechanisms, we studied six Andean Quechua Indians in La Raya, Peru (4,200 m) and at low altitude (less than 700 m) immediately upon arrival in Canada. The experimental strategy compared whole-body performance tests and single (calf) muscle work capacities in the Andeans with those in groups of sedentary, power-trained, and endurance-trained lowlanders. We used 31P nuclear magnetic resonance spectroscopy to monitor noninvasively changes in concentrations of phosphocreatine [( PCr]), [Pi], [ATP], [PCr]/[PCr] + creatine ([Cr]), [Pi]/[PCr] + [Cr], and pH in the gastrocnemius muscle of subjects exercising to fatigue. Our results indicate that the Andeans 1) are phenotypically unique with respect to measures of anaerobic and aerobic work capacity, 2) despite significantly lower anaerobic capacities, are capable of calf muscle work rates equal to those of highly trained power- and endurance-trained athletes, and 3) compared with endurance-trained athletes with significantly higher VO2max values and power-trained athletes with similar VO2max values, display, respectively, similar and reduced perturbation of all parameters related to the phosphorylation potential and to measurements of [Pi], [PCr], [ATP], and muscle pH derivable from nuclear magnetic resonance. Because the lactate paradox may be explained on the basis of tighter ATP demand-supplying coupling, we postulate that a similar mechanism may explain 1) the high calf muscle work capacities in the Andeans relative to measures of whole-body work capacity, 2) the VO2max paradox, and 3) anecdotal reports of exceptional work capacities in indigenous altitude natives.
G O Matheson; P S Allen; D C Ellinger; C C Hanstock; D Gheorghiu; D C McKenzie; C Stanley; W S Parkhouse; P W Hochachka
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Publication Detail:
Type:  Comparative Study; Journal Article    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  70     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  1991 May 
Date Detail:
Created Date:  1991-09-09     Completed Date:  1991-09-09     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1963-76     Citation Subset:  IM; S    
Sports Medicine Division, University of British Columbia, Vancouver, Canada.
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MeSH Terms
Acclimatization / physiology*
Adenosine Triphosphate / metabolism
Anoxia / metabolism
Energy Metabolism
Lactates / metabolism
Lactic Acid
Magnetic Resonance Spectroscopy
Muscle Contraction / physiology
Muscles / metabolism*
Oxygen Consumption
Phosphocreatine / metabolism
Reg. No./Substance:
0/Lactates; 50-21-5/Lactic Acid; 56-65-5/Adenosine Triphosphate; 67-07-2/Phosphocreatine

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

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