Endurance Performance at Altitude

The degree to which endurance exercise performance is diminished in acute hypoxia is variable and appears to be the result of several different physiological processes, however this research focuses on hypoxic pulmonary vasoconstriction (HPV). Sildenafil, a pulmonary vasodilator, has been used with mixed results to improve athletic performance in hypoxia. Because sildenafil has been shown to reduce HPV in some individuals, we believe that its effectiveness is closely related to the magnitude of the HPV response and the degree that individual exercise performance declines in hypoxia. This research will investigate the relationship between sildenafil, HPV, and exercise performance.