Document Detail


Superior exercise performance in lifelong Tibetan residents of 4,400 m compared with Tibetan residents of 3,658 m.
MedLine Citation:
PMID:  9537925     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Few environments challenge human populations more than high altitude, since the accompanying low oxygen pressures (hypoxia) are pervasive and impervious to cultural modification. Work capacity is an important factor in a population's ability to thrive in such an environment. The performance of work or exercise is a measure of the integrated functioning of the O2 transport system, with maximal O2 uptake (.VO2max) a convenient index of that function. Hypoxia limits the ability to transport oxygen: maximal O2 uptake decreases with ascent to high altitude, and years of high altitude residence do not restore sea level .VO2max values. Since Tibetans live and work at some of the highest altitudes in the world, their ability to exercise at very high altitude (>4,000 m) may define the limits of human adaptation to hypoxia. We transported 20 Tibetan lifelong residents of > or =4,400 m down to 3,658 m in order to compare them with 16 previously studied Tibetan residents of Lhasa (3,658 m). The two groups of Tibetans were matched for age, weight, and height. All studies were performed in Lhasa within 3 days of the 4,400 m Tibetans' arrival. Standard test protocol and criteria were used for attaining .VO2max on a Monark bicycle ergometer, while measuring oxygen uptake (.VO2, ml/kg - min STPD), heart rate (bpm), minute ventilation (VE, 1/min BTPS), and arterial oxygen saturation (SaO2, %). The 4,400 m compared with 3,658 m residents had, at maximal effort, similar .VO2 (48.5 +/- 1.2 vs. 51.2 +/- 1.4 ml/kg - min, P = NS), higher workload attained (211 +/- 6 vs. 177 +/- 7 watts, P < 0.01), lower heart rate(176 +/- 2 vs. 191 +/- 2 bpm, P < 0.01), lower ventilation (127 +/- 5 vs. 149 +/- 5 l/min BTPS, P < 0.01), and similar SaO2(81.9 +/- 1.0 vs. 83.7 +/- 1.2%, P = NS). Furthermore, over the range of submaximal workloads, 4,400 m compared with 3,658 m Tibetans had lower .VO2 (P < 0.01), lower heart rates (P < 0.01), and lower ventilation (P < 0.01) and SaO2 (P < 0.05). We conclude that Tibetans living at 4,400 m compared with those residing at 3,658 m achieve greater work performance for a given .VO2 at submaximal and maximal workloads with less cardiorespiratory effort.
Authors:
L S Curran; J Zhuang; T Droma; L G Moore
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  American journal of physical anthropology     Volume:  105     ISSN:  0002-9483     ISO Abbreviation:  Am. J. Phys. Anthropol.     Publication Date:  1998 Jan 
Date Detail:
Created Date:  1998-04-07     Completed Date:  1998-04-07     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0400654     Medline TA:  Am J Phys Anthropol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  21-31     Citation Subset:  IM; S    
Affiliation:
Department of Anthropology, University of Colorado at Denver, 80217-3364, USA.
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MeSH Terms
Descriptor/Qualifier:
Adult
Altitude*
Anoxia
Exercise / physiology*
Exercise Test
Heart Rate
Humans
Male
Oxygen Consumption / physiology
Physical Endurance / physiology*
Tibet

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


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