Lung function and gas exchange

Abstract

As the first step in the path for oxygen transport to the body, the response of the respiratory system is critical to maintaining an adequate level of function at high altitude. Environmental hypoxia, combined with cold and heavy exercise all contribute to considerable stress to the lung. Acute altitude exposure results in hypoxia, and a rapid and sustained increase in alveolar ventilation, with an associated fall in alveolar and arterial partial pressure of carbon dioxide. In addition cardiac output and pulmonary vascular pressures also increase. These changes along with any occurring as a result of altitude illness have the potential to alter pulmonary function and gas exchange. In addition, acclimatization to hypoxia of hours to days duration results in additional physiological changes overlying the acute changes. This review explores the changes in pulmonary function, as well as changes in pulmonary gas exchange at rest or during exercise that occur within the first hours to weeks of hypoxic exposure following ascent to high altitude.