Greater maximal O2 uptakes and vital capacities in Tibetan than Han residents of Lhasa

Sun, Shinfu; Droma, Tarshi; Zhang, J.G.; Tao, Jiale; Huang, Szu-Wei; McCullough, R. G.; McCullough, R. E.; Reeves, Christina; Reeves, John Τ.; Moore, Lorna G.

doi:10.1016/0034-5687(90)90015-q

Cited by 80 publications

(86 citation statements)

References 17 publications

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“…Our data demonstrated that the Tibetan subjects have higher values of SV coupled with higher Sa O 2 at maximal exercise than did the Hans. This result may be derived from either lower pulmonary arterial pressure (Ppa) (16) or higher myocardial contractility caused by relatively higher O 2 transport in the myocardium (30) or both.…”

Section: Exercise Performance Of Tibetan and Han Adolescentsmentioning

confidence: 99%

“…Although comparative studies of V O 2 max between high altitude natives and lowland residents at high-altitude have been done, the conclusions are controversial (10)(11)(12)(13)30). High-altitude adult natives in either Andean or Himalayan populations have higher exercise performance and maintain better arterial O 2 saturation (Sa O 2 ) during exercise compared with newcomers (17,20,30,38). These characteristics, which are associated with more efficient pulmonary gas exchange (38) and better adaptation to high-altitude stress, are acquired through many generations of lifelong high-altitude exposure.…”

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confidence: 99%

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Exercise performance of Tibetan and Han adolescents at altitudes of 3,417 and 4,300 m

Chen

Wang

et al. 1997

Journal of Applied Physiology

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Yoshimura. Exercise performance of Tibetan and Han adolescents at altitudes of 3,417 and 4,300 m. J. Appl. Physiol. 83(2): 661-667, 1997.-The difference was studied between O 2 transport in lifelong Tibetan adolescents and in newcomer Han adolescents acclimatized to high altitude. We measured minute ventilation, maximal O 2 uptake, maximal cardiac output, and arterial O 2 saturation during maximal exercise, using the incremental exercise technique, at altitudes of 3,417 and 4,300 m. The groups were well matched for age, height, and nutritional status. The Tibetans had been living at the altitudes for a longer period than the Hans (14.5 6 0.2 vs. 7.8 6 0.8 yr at 3,417 m, P , 0.01; and 14.7 6 0.3 vs. 5.3 6 0.7 yr at 4,300 m, P , 0.01, respectively). At rest, Tibetans had significantly greater vital capacity and maximal voluntary ventilation than the Hans at both altitudes. At maximal exercise, Tibetans compared with Hans had higher maximal O 2 uptake (42.2 6 1.7 vs. 36.7 6 1.2 ml · min 21 ·kg 21 at 3,417 m, P , 0.01; and 36.8 6 1.9 vs. 30.0 6 1.4 ml · min 21 ·kg 21 at 4,300 m, P , 0.01, respectively) and greater maximal cardiac output (12.8 6 0.3 vs. 11.4 6 0.2 l/min at 3,417 m, P , 0.01; 11.5 6 0.5 vs. 10.0 6 0.5 l/min at 4,300 m, P , 0.05, respectively). Although the differences in arterial O 2 saturation between Tibetans and Hans were not significant at rest and during mild exercise, the differences became greater with increases in exercise workload at both altitudes. We concluded that exposure to high altitude from birth to adolescence resulted in an efficient O 2 transport and a greater aerobic exercise performance that may reflect a successful adaptation to life at high altitude. cardiac output; maximal oxygen consumption; ventilation; developmental adaptation; genetic adaptation MAXIMAL O 2 UPTAKE (V O 2 max ), an integrated index of the overall functional capacity of the O 2 transport system, invariably decreases with altitude during both acute and chronic exposure to high altitude in lowland adults (31,34). This is due to the reduction of ambient O 2 pressure at high altitude. Although comparative studies of V O 2 max between high altitude natives and lowland residents at high-altitude have been done, the conclusions are controversial (10-13, 30). High-altitude adult natives in either Andean or Himalayan populations have higher exercise performance and maintain better arterial O 2 saturation (Sa O 2 ) during exercise compared with newcomers (17,20,30,38). These characteristics, which are associated with more efficient pulmonary gas exchange (38) and better adaptation to high-altitude stress, are acquired through many generations of lifelong high-altitude exposure. The Tibetans are believed to have lived at high altitude longer than other highaltitude residents. The effects of high-altitude hypoxia on the physiological responses of Tibetan and Han adolescents to exercise have never been reported. Whether the pulmonary adaptations in humans are determined purely by environment or relate to genetic character...

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Section: Exercise Performance Of Tibetan and Han Adolescentsmentioning

confidence: 99%

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confidence: 99%

Exercise performance of Tibetan and Han adolescents at altitudes of 3,417 and 4,300 m

Chen

Wang

et al. 1997

Journal of Applied Physiology

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“…Typically, Tibetans average at least 1 g/dL and as much as approximately 3.5 gm/dL (i.e. approximately 10-20%) lower hemoglobin concentration in comparison with their Andean counterparts (14)(15)(16) or acclimatized lowlanders, such as the Han who have moved to altitudes above 2,500 m (4,(17)(18)(19)(20)(21)(22)(23). This suggests that Tibetans have evolved a blunted erythropoietic response to high-altitude hypoxia.…”

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confidence: 99%

Natural selection on EPAS1 ( HIF2α ) associated with low hemoglobin concentration in Tibetan highlanders

Beall

Cavalleri

Deng

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

730

770

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By impairing both function and survival, the severe reduction in oxygen availability associated with high-altitude environments is likely to act as an agent of natural selection. We used genomic and candidate gene approaches to search for evidence of such genetic selection. First, a genome-wide allelic differentiation scan (GWADS) comparing indigenous highlanders of the Tibetan Plateau (3,200-3,500 m) with closely related lowland Han revealed a genome-wide significant divergence across eight SNPs located near EPAS1. This gene encodes the transcription factor HIF2α, which stimulates production of red blood cells and thus increases the concentration of hemoglobin in blood. Second, in a separate cohort of Tibetans residing at 4,200 m, we identified 31 EPAS1 SNPs in high linkage disequilibrium that correlated significantly with hemoglobin concentration. The sex-adjusted hemoglobin concentration was, on average, 0.8 g/dL lower in the major allele homozygotes compared with the heterozygotes. These findings were replicated in a third cohort of Tibetans residing at 4,300 m. The alleles associating with lower hemoglobin concentrations were correlated with the signal from the GWADS study and were observed at greatly elevated frequencies in the Tibetan cohorts compared with the Han. High hemoglobin concentrations are a cardinal feature of chronic mountain sickness offering one plausible mechanism for selection. Alternatively, as EPAS1 is pleiotropic in its effects, selection may have operated on some other aspect of the phenotype. Whichever of these explanations is correct, the evidence for genetic selection at the EPAS1 locus from the GWADS study is supported by the replicated studies associating function with the allelic variants.chronic mountain sickness | high altitude | human genome variation | hypoxia | hypoxia-inducible factor

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“…It has been suggested that diffusion capacity could be a decisive factor for oxygen transport during maximal exercise at high altitude (Chen et al, 1997), and De Meer et al summarized that an increase in pulmonary diffusion capacity facilitates oxygen delivery to the tissues in both children and adults living at higher altitudes (de Meer et al, 1995). As shown in several studies, an increased lung volume is also accompanied by an increased pulmonary diffusion capacity (DeGraff et al, 1970;Guleria et al, 1971;Cerny et al, 1973;Johnson et al, 1985;Sun et al, 1990;Armstrong and Welsman, 1994). Moreover, large lung volumes and chest circumferences have been reported among schoolchildren and adolescents who are native to high altitude (Frisancho, 1969;Beall et al, 1977), though not in immigrants acclimatized to high altitude (Frisancho et al, 1973).…”

Section: Discussionmentioning

confidence: 85%

“…Most previous studies have shown that native Tibetan adults (Sun et al, 1990;Groves et al, 1993;Zhuang et al, 1993;1996) and adolescents (Chen et al, 1997) achieve a superior exercise capacity compared to Han Chinese immigrants. However, a few studies have shown that native Tibetan adults attained a higher exercise capacity, but a similar (Niu et al, 1995) or lower (Ge et al,1994) peak oxygen uptake ( _ VO 2peak ).…”

Section: Introductionmentioning

confidence: 99%

Exercise Capacity and Selected Physiological Factors by Ancestry and Residential Altitude: Cross-Sectional Studies of 9–10-Year-Old Children in Tibet

Bianba

Berntsen

Andersen

et al. 2014

High Altitude Medicine & Biology

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Bianba, Sveinung Bernsten, Lars Bo Andersen, Hein Stegum, Ouzhuluobu, Per Nafstad, Tianyi Wu, and Espen Bjertness. Exercise capacity and selected physiological factors by ancestry and residential altitude-Crosssectional studies of 9-10-year-old children in Tibet. High Alt Med Biol. 15:162-169, 2014.-Aim: Several physiological compensatory mechanisms have enabled Tibetans to live and work at high altitude, including increased ventilation and pulmonary diffusion capacity, both of which serve to increase oxygen transport in the blood. The aim of the present study was to compare exercise capacity (maximal power output) and selected physiological factors (arterial oxygen saturation and heart rate at rest and during maximal exercise, resting hemoglobin concentration, and forced vital capacity) in groups of native Tibetan children living at different residential altitudes (3700 vs. 4300 m above sea level) and across ancestry (native Tibetan vs. Han Chinese children living at the same altitude of 3700 m). Methods: A total of 430 9-10-year-old native Tibetan children from Tingri (4300 m) and 406 native Tibetanand 406 Han Chinese immigrants (77% lowland-born and 33% highland-born) from Lhasa (3700 m) participated in two cross-sectional studies. The maximal power output (W max ) was assessed using an ergometer cycle. Results: Lhasa Tibetan children had a 20% higher maximal power output (watts/kg) than Tingri Tibetan and 4% higher than Lhasa Han Chinese. Maximal heart rate, arterial oxygen saturation at rest, lung volume, and arterial oxygen saturation were significantly associated with exercise capacity at a given altitude, but could not fully account for the differences in exercise capacity observed between ancestry groups or altitudes. Conclusions: The superior exercise capacity in native Tibetans vs. Han Chinese may reflect a better adaptation to life at high altitude. Tibetans at the lower residential altitude of 3700 m demonstrated a better exercise capacity than residents at a higher altitude of 4300 m when measured at their respective residential altitudes. Such altitude-or ancestry-related difference could not be fully attributed to the physiological factors measured.

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Greater maximal O2 uptakes and vital capacities in Tibetan than Han residents of Lhasa

Cited by 80 publications

References 17 publications

Exercise performance of Tibetan and Han adolescents at altitudes of 3,417 and 4,300 m

Exercise performance of Tibetan and Han adolescents at altitudes of 3,417 and 4,300 m

Natural selection on EPAS1 ( HIF2α ) associated with low hemoglobin concentration in Tibetan highlanders

Exercise Capacity and Selected Physiological Factors by Ancestry and Residential Altitude: Cross-Sectional Studies of 9–10-Year-Old Children in Tibet

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