Sildenafil and bosentan improve arterial oxygenation during acute hypoxic exercise: a controlled laboratory trial.

Objectives: Sildenafil and, recently, bosentan have been reported to increase arterial saturation and exercise capacity at altitude. The mechanisms behind this are still poorly defined but may be related to attenuation of hypoxic pulmonary vasoconstriction (HPV) and improved gas exchange. This study was designed to examine and compare the effect of sildenafil and bosentan on pulmonary gas exchange during acute hypoxic exercise in a controlled laboratory setting.