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Proceedings Paper

High-altitude physiology: lessons from Tibet
Author(s): Peter D. Wagner; Tatum S. Simonson; Guan Wei; Harrieth Wagner; Tanna Wuren; Ma Yan; Ga Qin; Rili Ge
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Paper Abstract

Polycythemia is a universal lowlander response to altitude; healthy Andean high-altitude natives also have elevated [Hb]. While this may enhance O2 transport to tissues, studies have shown that acute isovolumic changes in [Hb] do not affect exercise capacity. Many high-altitude Tibetans have evolved sea-level values of [Hb], providing a natural opportunity to study this issue. In 21 young healthy male Tibetans with [Hb] between 15 and 23 g/dl, we measured VO2MAX and O2 transport capacity at 4200m. VO2MAX was higher when [Hb] was lower (P<0.05), enabled by both higher cardiac output and muscle O2 diffusional conductance, but neither ventilation nor the alveolar-arterial PO2 difference (AaPO2) varied with [Hb]. In contrast, Andean high altitude natives remain polycythemic with larger lungs and higher lung diffusing capacity, a smaller exercising AaPO2, and lower ventilation. The challenges now are (1) to understand the different adaptive pathways used by Andeans and Tibetans, and (2) to determine in Tibetans whether, during evolution, reduced [Hb] appeared first, causing compensatory cardiac and muscle adaptations, or if enhanced cardiac function and muscle O2 transport capacity appeared first, permitting secondary reduction in [Hb]. For (2), further research is necessary to determine the basis of enhanced cardiac function and muscle O2 transport, and identify molecular targets of evolution in heart and muscle. Putative mutations can then be timed and compared to appearance of those affecting [Hb].

Paper Details

Date Published: 29 May 2013
PDF: 4 pages
Proc. SPIE 8723, Sensing Technologies for Global Health, Military Medicine, and Environmental Monitoring III, 87230S (29 May 2013); doi: 10.1117/12.2020038
Show Author Affiliations
Peter D. Wagner, Univ. of California, San Diego (United States)
Tatum S. Simonson, Univ. of California, San Diego (United States)
Guan Wei, Qinghai Univ. School of Medicine (China)
Harrieth Wagner, Univ. of California, San Diego (United States)
Tanna Wuren, Qinghai Univ. School of Medicine (China)
Ma Yan, Qinghai Univ. School of Medicine (China)
Ga Qin, Qinghai Univ. School of Medicine (China)
Rili Ge, Qinghai Univ. School of Medicine (China)


Published in SPIE Proceedings Vol. 8723:
Sensing Technologies for Global Health, Military Medicine, and Environmental Monitoring III
Šárka O. Southern, Editor(s)

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