Document Detail


Muscle tissue adaptations of high-altitude natives to training in chronic hypoxia or acute normoxia.
MedLine Citation:
PMID:  8941514     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Twenty healthy high-altitude natives, residents of La Paz, Bolivia (3,600 m), participated in 6 wk of endurance exercise training on bicycle ergometers, 5 times/wk, 30 min/session, as previously described in normoxia-trained sea-level natives (H. Hoppeler, H. Howald, K. E. Conley, S. L. Lindstedt, H. Claassen, P. Vock, and E. R. Weibel. J. Appl. Physiol. 59: 320-327, 1985). A first group of 10 subjects was trained in chronic hypoxia (HT; barometric pressure = 500 mmHg; inspired O2 fraction = 0.209); a second group of 10 subjects was trained in acute normoxia (NT; barometric pressure = 500 mmHg; inspired O2 fraction = 0.314). The workloads were adjusted to approximately 70% of peak O2 consumption (VO2peak) measured either in hypoxia for the HT group or in normoxia for the NT group. VO2peak determination and biopsies of the vastus lateralis muscle were taken before and after the training program. VO2peak in the HT group was increased (14%) in a way similar to that in NT sea-level natives with the same protocol. Moreover, VO2peak in the NT group was not further increased by additional O2 delivery during the training session. HT or NT induced similar increases in muscle capillary-to-fiber ratio (26%) and capillary density (19%) as well as in the volume density of total mitochondria and citrate synthase activity (45%). It is concluded that high-altitude natives have a reduced capillarity and muscle tissue oxidative capacity; however, their training response is similar to that of sea-level residents, independent of whether training is carried out in hypobaric hypoxia or hypobaric normoxia.
Authors:
D Desplanches; H Hoppeler; L Tüscher; M H Mayet; H Spielvogel; G Ferretti; B Kayser; M Leuenberger; A Grünenfelder; R Favier
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Publication Detail:
Type:  Clinical Trial; Controlled Clinical Trial; 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 Nov 
Date Detail:
Created Date:  1997-03-13     Completed Date:  1997-03-13     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:  1946-51     Citation Subset:  IM; S    
Affiliation:
Unité Mixte de Recherche, Laboratoire de Physiologie, Faculté de Médecine, Lyon, France.
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MeSH Terms
Descriptor/Qualifier:
Acclimatization / physiology*
Adult
Altitude*
Anoxia / physiopathology*
Capillaries / physiology,  ultrastructure
Chronic Disease
Histocytochemistry
Humans
Male
Microscopy, Electron
Muscle Fibers, Skeletal / physiology,  ultrastructure
Muscle, Skeletal / metabolism,  physiology*,  ultrastructure
Oxygen Consumption / physiology
Physical Endurance
Physical Fitness*

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


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