Document Detail


Hypoxic ventilatory responsiveness in Tibetan compared with Han residents of 3,658 m.
MedLine Citation:
PMID:  8444707     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Lifelong high-altitude residents of North and South America acquire blunted hypoxic ventilatory responses and exhibit decreased ventilation compared with acclimatized newcomers. The ventilatory characteristics of Himalayan high-altitude residents are of interest in the light of their reportedly lower hemoglobin levels and legendary exercise performance. Until recently, Sherpas have been the only Himalayan population available for study. To determine whether Tibetans exhibited levels of ventilation and hypoxic ventilatory drives that were as great as acclimatized newcomers, we compared 27 lifelong Tibetan residents of Lhasa, Tibet, China (3,658 m) with 30 acclimatized Han ("Chinese") newcomers matched for age, body size, and extent of exercise training. During room air breathing, minute ventilation was greater in the Tibetan than in the Han young men because of an increased respiratory frequency, but arterial O2 saturation and end-tidal PCO2 did not differ, indicating similar levels of effective alveolar ventilation. The Tibetan subjects had higher hypoxic ventilatory response shape parameter A values and hypercapnic ventilatory responsiveness than the Han subjects. Among the Han subjects, duration of high-altitude residence correlated with the degree of blunting of the hypoxic ventilatory drive. Paradoxically, hyperoxia (inspired O2 fraction 0.70) increased minute ventilation and decreased end-tidal PCO2 in the Tibetan but not in the Han men. We concluded that lifelong Tibetan residents of high altitude neither hypoventilated nor exhibited blunted hypoxic ventilatory responses compared with acclimatized Han newcomers, suggesting that the effects of lifelong high-altitude residence on ventilation and ventilatory response to hypoxia differ in Tibetan compared with other high-altitude populations.
Authors:
J Zhuang; T Droma; S Sun; C Janes; R E McCullough; R G McCullough; A Cymerman; S Y Huang; J T Reeves; L G Moore
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  74     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  1993 Jan 
Date Detail:
Created Date:  1993-04-06     Completed Date:  1993-04-06     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:  303-11     Citation Subset:  IM    
Affiliation:
Tibet Institute of Medical Sciences, Lhasa, China.
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MeSH Terms
Descriptor/Qualifier:
Adult
Altitude*
Anoxia / physiopathology*
Child
China / ethnology
Hemoglobins / metabolism
Humans
Hypercapnia / physiopathology
Male
Oxygen Consumption / physiology
Respiratory Mechanics / physiology*
Smoking / physiopathology
Vital Capacity
Grant Support
ID/Acronym/Agency:
HD-000681/HD/NICHD NIH HHS; HL-14985/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
0/Hemoglobins

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