Hemoglobin levels in persons of tibetan ancestry living at high altitude.

The mean hemoglobin level of persons of Tibetan ancestry living at 4000 m in the Nepal Himalayas was found similar to that expected at an altitude of 2300 m and an arterial O2 saturation of 92%. Plasma volumes were normal, and deficiency states and hemoglobinopathies were not significant. Possible reasons for this finding are discussed.