Human adaptation to high‐altitude: A contemporary comparison of the oxygen cascade in Andean, Tibetan and Ethiopian highlanders
Bibliographic record
Abstract
Abstract Human populations native to high altitude have evolved distinct physiological adaptations to chronic hypoxia. This adaptation is evident in the O 2 transport cascade. In this review, with brief inclusion of the related genetic adaptations, we compare the O 2 cascade across three well‐characterized high‐altitude populations: Andeans (Aymara and Quechua), Tibetans/Sherpa and Ethiopians (Amhara and Oromo). We contrast the steps of the O 2 cascade: (1) ventilation; (2) pulmonary O 2 diffusion; (3) cardiac output and circulation; (4) haematological traits; and (5) tissue O 2 utilization. Tibetans exhibit a robust hypoxic ventilatory response and efficient pulmonary diffusion capacity. They maintain preserved cardiac function with optimized muscle energetics. These adaptations are supported by enhanced tissue blood flow and greater muscle capillary density. Andeans demonstrate a blunted ventilatory response and marked remodelling of the pulmonary circulation, resulting in elevated pulmonary arterial pressure and mild but persistent right ventricular hypertrophy along with lifelong sympathetic overactivity. They also show strong haematological adaptations, with increased haemoglobin concentration. Ethiopians, particularly Amhara highlanders, show ventilatory status close to sea‐level values, with limited pulmonary and cerebral vasoreactivity to hypoxia. Although data remain limited, the Amhara highlanders exhibit higher oxygen saturation and enhanced tissue blood flow in comparison to Oromo counterparts. In conclusion, these physiological (i.e., O 2 cascade) differences provide evidence of the diverse patterns of evolutionarily adaptive responses to the stresses of high‐altitude hypoxia. Further research comparing the O 2 cascade across these Indigenous populations will enhance our understanding of the genetic and physiological adaptations to life at high altitude.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".