Effect of Exposure to Simulated High Altitude on Human Red Cell Phosphates and Oxygen Affinity of Hemoglobin. Influence of Exercise

The effect of exposure to simulated high altitude (4,500 m) on the concentration of 2,3-diphosphoglycerate (2,3-DPG) and adenosine triphosphate (ATP) in the red cell and the oxygen affinity of hemoglobin (P50) (measured at PCO2=40 mm Hg and corrected to plasma pH=7.40) was studied. It was found that a moderate physical activity is a condition for the previously reported decrease in the oxygen affinity during acclimatization to high altitude, and that this decrease is exclusively due to an increase in the concentration of 2,3-DPG in the red cell. A rapid and pronounced decrease in the extracellular concentration of inorganic phosphate was found in resting as well as exercising individuals.