Cardiopulmonary exercise testing (CPET) in hyperoxia and hypoxia has several applications, stemming from characterization of abnormal physiological response profiles associated with exercise intolerance. As altered oxygenation can impact the performance of gas-concentration and flow sensors and pulmonary gas exchange algorithms, integrated CPET system function requires validation under these conditions. Also, as oxygenation status can influence peak [Formula: see text]o2, care should be taken in the selection of work-rate incrementation rates when CPET performance is to be compared with normobaria at sea level. CPET has been used to evaluate the effects of supplemental O2 on exercise intolerance in chronic obstructive pulmonary disease, interstitial pulmonary fibrosis, and cystic fibrosis at sea level. However, identification of those CPET indices likely to be predictive of supplemental O2 outcomes for exercise tolerance at altitude in such patients is lacking. CPET performance with supplemental O2 in respiratory patients residing at high altitudes is also poorly studied. Finally, CPET has the potential to give physiological and clinical information about acute and chronic mountain sickness, high-altitude pulmonary edema, and high-altitude cerebral edema. It may also translate high-altitude acclimatization and adaptive processes in healthy individuals into intensive care medical practice.
Keywords: altitude; chronic obstructive pulmonary disease; exercise capacity; exercise testing; hyperoxia.