Man's respiratory response during and after acclimatization to high altitude.

I NCREASED pulmonary ventilation in response to lowered oxygen pressures has long been recognized in man. For a given oxygen pressure, however, this response is not the same for acclimatized and unacclimatized man. In order to analyze the changes which occur during the process of adaptation, various types of experiments have been designed. It is our objective I) to describe the difference in alveolar air composition between persons acclimatized to various altitudes and persons residing near sea-level who are acutely exposed to similar altitudes and to predict on this basis the ventilatory acclimatization for any altitude, 2) to verify this prediction in experiments on 3 subjects acclimatized to an altitude of 9500 feet for a period of 3 weeks, 3) to describe the respiratory response of men acutely exposed to lower and higher oxygen pressures after acclimatization to various altitudes, and 4) to present data which indicate a greater sensitivity of the respiratory system to CO2 after acclimatization to altitude. Diference between Alveolar Air Composition and Ventilation oj A cchatized rind Ckzcclimatized Man at Similar Oxygen Pressures. The alveolar gas composition of permanent residents as well as sojourners acclimatized to altitude have been collected from reports of various mountain expeditions and are presented in table T. The alveolar respiratory quotient has been computed in each case from the alveolar gas equation (I, 2).