Please use this identifier to cite or link to this item: http://hdl.handle.net/10553/50915
Title: Why are high-altitude natives so strong at altitude? Maximal oxygen transport to the muscle cell in altitude natives
Authors: Lundby, Carsten
Calbet, Jose A. L. 
UNESCO Clasification: 241106 Fisiología del ejercicio
Keywords: Sherpa
Tibet
Andes
Exercise
Endurance
Issue Date: 2016
Publisher: 0065-2598
Journal: Advances in Experimental Medicine and Biology 
Abstract: In hypoxia aerobic exercise performance of high-altitude natives is suggested to be superior to that of lowlanders; i.e., for a given altitude natives are reported to have higher maximal oxygen uptake (VO2max). The likely basis for this is a higher pulmonary diffusion capacity, which in turn ensures higher arterial O2 saturation (SaO2) and therefore also potentially a higher delivery of O2 to the exercising muscles. This review focuses on O2 transport in high-altitude Aymara. We have quantified femoral artery O2 delivery, arterial O2 extraction and calculated leg VO2 in Aymara, and compared their values with that of acclimatizing Danish lowlanders. All subjects were studied at 4100 m. At maximal exercise SaO2 dropped tremendously in the lowlanders, but did not change in the Aymara. Therefore arterial O2 content was also higher in the Aymara. At maximal exercise however, fractional O2 extraction was lower in the Aymara, and the a-vO2 difference was similar in both populations. The lower extraction levels in the Aymara were associated with lower muscle O2 conductance (a measure of muscle diffusion capacity). At any given submaximal exercise intensity, leg VO2 was always of similar magnitude in both groups, but at maximal exercise the lowlanders had higher leg blood flow, and hence also higher maximum leg VO2. With the induction of acute normoxia fractional arterial O2 extraction fell in the highlanders, but remained unchanged in the lowlanders. Hence high-altitude natives seem to be more diffusion limited at the muscle level as compared to lowlanders. In conclusion Aymara preserve very high SaO2 during hypoxic exercise (likely due to a higher lung diffusion capacity), but the effect on VO2max is reduced by a lower ability to extract O2 at the muscle level.
URI: http://hdl.handle.net/10553/50915
ISBN: 978-1-4899-7676-5
ISSN: 0065-2598
DOI: 10.1007/978-1-4899-7678-9_5
Source: Hypoxia: Translation In Progress[ISSN 0065-2598],v. 903, p. 65-81
Appears in Collections:Capítulo de libro
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