Tolerance to Hypoxia

Abstract People living at sea level have poor tolerance to hypoxia. In striking contrast, humans experiencing hypoxia at high altitude live very well. How is it possible for man to tolerate extreme hypoxia at high altitude? In this article we propose a hypothesis that potentially explains the tolerance to hypoxia at high altitude. Close examination of values of hemoglobin and PaCO2 for an altitude of 3510 m  demonstrate that an increase in hemoglobin (Hb) and a decrease in arterial carbon dioxide tension (PaCO2) are two essential changes that occur on high altitude exposure. We propose a formula : tolerance to hypoxia= Hb/PaCO2 * 3.01.  We present evidence that the relationship between Hb and PaCO2 explains the tolerance to hypoxia at high altitude. Full article PDF citation: Gustavo R. Zubieta-Calleja, Gustavo Ardaya, Natalia Zubieta-De Urioste, Poul-Erik Paulev and Gustavo Zubieta-Castillo,, April 10, 2013. Formula originally published at: