Ethiopians reveal high-altitude twist

There’s more than one way for people living at extremely high altitudes to adapt to so-called thin air. Biologically, there must be at least three ways, according to a report in an upcoming Proceedings of the National Academy of Sciences.

A team led by Cynthia M. Beall of Case Western Reserve University in Cleveland obtained blood samples and medical data from 236 Ethiopian villagers living more than 2 miles above sea level. The villagers displayed an average blood concentration of oxygen-rich hemoglobin comparable to that already reported for sea-level populations. Oxygen saturation of hemoglobin among the Ethiopians also roughly equaled measurements made in lowland groups. The researchers now plan to look for a biological mechanism to explain how these people survive at their high altitude.

Previous research directed by Beall had found a high blood-hemoglobin concentration but low hemoglobin-oxygen saturation among Andean highlanders. Beall also reported that high-altitude Tibetans possess a blood-hemoglobin concentration similar to sea-level folk combined with low oxygen saturation.

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Bruce Bower has written about the behavioral sciences for Science News since 1984. He writes about psychology, anthropology, archaeology and mental health issues.