Comparisons of oxygen transport between Tibetan and Han residents at moderate altitude

Ge, Ri-Li; Lun, Gao-Wa He; Chen, Qiuhong; Li, Hailing; Gen, Ding; Kubo, Keishi; Matsuzawa, Y.; Fujimoto, Keisaku; Yoshimura, Kazuhiko; Takeoka, Michiko; Kobayashi, Toshio

doi:10.1580/1080-6032(1995)006[0391:cootbt]2.3.co;2

Cited by 28 publications

(21 citation statements)

References 24 publications

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“…Tibetan and Sherpa exhibit elevated heart rates compared to lowlanders at altitude (Pugh, 1962;1964;Sun et al, 1990;Wu, 1990) and, compared to Han Chinese, greater stroke volume, cardiac output (Wu, 1990;Ge, 1995;Chen et al, 1997), and less right heart hypertrophy (Halperin et al, 1998). Sherpa at altitude also exhibit components of mechanical reserve typically observed only among lowlanders at low altitude as well as a relatively smaller left ventricle (Stembridge et al, 2014).…”

Section: Cardiac and Metabolic Differences Observed In Highlandersmentioning

confidence: 99%

Altitude Adaptation: A Glimpse Through Various Lenses

Simonson

2015

High Altitude Medicine & Biology

133

141

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Simonson, Tatum S. Altitude adaptation: A glimpse through various lenses. High Alt Med Biol 16:125-137, 2015.-Recent availability of genome-wide data from highland populations has enabled the identification of adaptive genomic signals. Some of the genomic signals reported thus far among Tibetan, Andean, and Ethiopian are the same, while others appear unique to each population. These genomic findings parallel observations conveyed by decades of physiological research: different continental populations, resident at high altitude for hundreds of generations, exhibit a distinct composite of traits at altitude. The most commonly reported signatures of selection emanate from genomic segments containing hypoxia-inducible factor (HIF) pathway genes. Corroborative evidence for adaptive significance stems from associations between putatively adaptive gene copies and sea-level ranges of hemoglobin concentration in Tibetan and Amhara Ethiopians, birth weights and metabolic factors in Andeans and Tibetans, maternal uterine artery diameter in Andeans, and protection from chronic mountain sickness in Andean males at altitude. While limited reports provide mechanistic insights thus far, efforts to identify and link precise genetic variants to molecular, physiological, and developmental functions are underway, and progress on the genomics front continues to provide unprecedented movement towards these goals. This combination of multiple perspectives is necessary to maximize our understanding of orchestrated biological and evolutionary processes in native highland populations, which will advance our understanding of both adaptive and non-adaptive responses to hypoxia.

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Section: Cardiac and Metabolic Differences Observed In Highlandersmentioning

confidence: 99%

Altitude Adaptation: A Glimpse Through Various Lenses

Simonson

2015

High Altitude Medicine & Biology

133

141

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“…There are numerous comparative studies showing that high altitude (HA) native populations in the Andes and Himalayas maintain higher arterial oxygen saturation (SaO 2 ) during exercise at HA compared to acclimatized lowland groups (Sun et al, 1990;Ge et al, 1993Ge et al, , 1995Zhuang et al, 1996;Chen et al, 1997;Schoene et al, 1990;Favier et al, 1995). In addition, Tibetan native neonates born at HA have higher resting SaO 2 compared to neonates born to acclimatized lowland mothers (Niermeyer et al, 1995).…”

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confidence: 99%

“…At least three modes of adaptation may explain the higher exercise SaO 2 of Andeans and Himalayans, including: physiological acclimatization (short-term and reversible), developmental adaptation (fixed traits acquired during the period growth and development), and genetic adaptation (Lasker, 1969). However, developmental and/or genetic mechanisms appear most likely in the case of the exercise SaO 2 phenotype, i.e., while physiological acclimatization to HA does result in a modest improvement in resting and exercise SaO 2 (Bender et al, 1989;Huang et al, 1984), even fully acclimatized lowland groups do not attain the high SaO 2 during exercise typically seen in Andeans and Himalayans (Ge et al, 1995: Zhuang et al, 1996Favier et al, 1995).…”

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confidence: 99%

Higher arterial oxygen saturation during submaximal exercise in Bolivian Aymara compared to European sojourners and Europeans born and raised at high altitude

Brutsaert

Araoz

Soria

et al. 2000

Am. J. Phys. Anthropol.

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Arterial oxygen saturation (SaO(2)) was measured at 3,600-3,850 m by pulse oximetry at rest and during submaximal exercise in three study groups: 1) highland Aymara natives of the Bolivian altiplano (n = 25); 2) lowland European/North American sojourners to the highlands with at least 2 months of acclimatization time to 3,600 m (n = 27); and 3) subjects of European ancestry born and raised at 3,600 m (n = 22). Aymara subjects maintained approximately 1 percentage point higher SaO(2) during submaximal work up to 70% of their maximal work capacity, and showed a smaller rate of decline in SaO(2) with increasing work compared to both European study groups. The higher-exercise SaO(2) of Aymara compared to Europeans born and raised at 3,600 m suggests genetic adaptation. The two European study groups, who differed by exposure to high altitude during their growth and development period, did not show any significant difference in either resting or exercise SaO(2). This suggests that the developmental mode of adaptation is less important than the genetic mode of adaptation in determining exercise SaO(2). A weak correlation was detected (across study groups only) between the residual forced vital capacity (FVC) and the residual SaO(2) measured at the highest level of submaximal work output (P = 0.024, R = 0.26). While firm conclusions based on this correlation are problematic, it is suggested that a part of the higher SaO(2) observed in Aymara natives is due to a larger lung volume and pulmonary diffusion capacity for oxygen. Results from this study are compared to similar studies conducted with Tibetan natives, and are interpreted in light of recent quantitative genetic analyses conducted in both the Andes and Himalayas.

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“…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)(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).…”

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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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Comparisons of oxygen transport between Tibetan and Han residents at moderate altitude

Cited by 28 publications

References 24 publications

Altitude Adaptation: A Glimpse Through Various Lenses

Altitude Adaptation: A Glimpse Through Various Lenses

Higher arterial oxygen saturation during submaximal exercise in Bolivian Aymara compared to European sojourners and Europeans born and raised at high altitude

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

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