Document Detail

Lactate and epinephrine during exercise in altitude natives.
MedLine Citation:
PMID:  9018496     Owner:  NLM     Status:  MEDLINE    
We tested the hypothesis that the reported low blood lactate accumulation ([La]) during exercise in altitude-native humans is refractory to hypoxianormoxia transitions by investigating whether acute changes in inspired O2 fraction (FIo2) affect the [La] vs. power output (W) relationship or, alternatively, as reported for lowlanders, whether changes in [La] vs. W on changes in FIo2 are related to changes in blood epinephrine concentration ([Epi]). Altitude natives [n = 8, age 24 +/- 1 (SE) yr, body mass 62 +/- 3 kg, height 167 +/- 2 cm] in La Paz, Bolivia (3,600 m) performed incremental exercise with two legs and one leg in chronic hypoxia and acute normoxia (AN). Submaximal one- and two-leg O2 uptake (Vo2) vs. W relationships were not altered by FIo2. AN increased two-leg peak Vo2 by 10% and peak W by 7%. AN paradoxically decreased one-leg peak Vo2 by 7%, whereas peak W remained the same. The [La] vs. W relationships were similar to those reported in unacclimatized lowlanders. There was a shift to the right on AN, and maximum [La] was reduced by 7 and 8% for one- and two-leg exercises, respectively. [Epi] and [La] were tightly related (mean r = 0.81) independently of FIo2. Thus normoxia attenuated the increment in both [La] and [Epi] as a function of W, whereas the correlation between [La] and [Epi] was unaffected. These data suggest loose linkage of glycolysis to oxidative phosphorylation under influence from [Epi]. In conclusion, high-altitude natives appear to be not fundamentally different from lowlanders with regard to the effect of acute changes in FIo2 on [La] during exercise.
B Kayser; R Favier; G Ferretti; D Desplanches; H Spielvogel; H Koubi; B Sempore; H Hoppeler
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  81     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  1996 Dec 
Date Detail:
Created Date:  1997-04-09     Completed Date:  1997-04-09     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:  2488-94     Citation Subset:  IM; S    
Département de Physiologie, Centre Médical Universitaire, Universität Bern, Switzerland.
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MeSH Terms
Epinephrine / metabolism*
Exercise / physiology*
Lactates / metabolism*
Reg. No./Substance:
0/Lactates; 51-43-4/Epinephrine

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