Every breath you take: acclimatisation at altitude

Abstract

The major challenge of going to altitude is related to the hypoxic environment; and of all the acute compensatory responses to hypobaric hypoxia at altitude, hyperventilation is usually considered the most critical for adequate acclimatisation. Hypocapnia minimises the inspired to alveolar difference in the partial pressure of oxygen, and through the concurrent alkalosis shifts the oxyhaemoglobin dissociation curve towards the left, both of which facilitate an increased oxygen uptake in the lungs at low partial pressures of oxygen. However, hypocapnia-induced cerebral arteriolar vasoconstriction as well as the left-shifted oxygen dissociation curve may reduce oxygen availability to the brain.