VIII. The changes in the breathing and the blood at various high altitudes

Abstract

In connection with the Anglo-American Pike’s Peak Expedition (1911), and simultaneously with the work on the summit of Pike’s Peak, Colorado, U. S. A., the following experiments were made in Colorado during the months of July and August, 1911, at altitudes varying from 5000 to 12,500 feet, for the purpose of determining the changes in the alveolar air and in the percentage of hæmoglobin in the blood of persons residing permanently at such heights. Haldane and Priestley showed that normally the lung ventilation is so regulated as to maintain during rest a definite mean alveolar carbonic acid pressure, and it is known that at high altitudes the breathing is regulated to a lower alveolar CO 2 pressure than is the case at sea-level. It is also known that an increase in the percentage of hæmoglobin occurs with a rise in altitude.