Sildenafil is a pulmonary vasodilator that has potential to mitigate the decrement in endurance performance caused by hypoxic pulmonary vasoconstriction. The purpose of this study was to determine the effects of sildenafil on pulmonary artery pressure, cardiac output, pulse oxygen saturation, and exercise performance at moderate simulated altitude. We hypothesized that sildenafil would reduce the decline in exercise performance in hypoxia by blunting the rise in pulmonary artery pressure and causing a relative increase in cardiac output and oxygen saturation. Twelve endurance trained men performed three experimental cycling trials at sea level and simulated moderate altitude of 3,000m (F_IO₂ = 0.147) after ingesting either a placebo or sildenafil 50 mg capsule in a double blinded fashion. Each test consisted of a warmup period, a 15-minute steady state period at 60% of peak power output, and a 16.1 km time-trial. All subjects experienced a decline in maximal exercise capacity in hypoxia that ranged from 6% to 24%. This decline was correlated with the reduction in pulse oxygen saturation in hypoxic maximal exercise. Sildenafil had no effect on pulmonary artery pressure, cardiac output, or pulse oxygen saturation measured during steady state exercise. There was no effect of sildenafil on mean power output during the time-trial. During high intensity cycle exercise in acute, moderate hypoxia pulmonary artery pressure is unaffected by sildenafil and does not appear to influence cardiovascular function or exercise performance.

西地那非是一种肺血管扩张药，具有缓解由低氧性肺血管收缩引起的耐力表现下降的潜力。这项研究的目的是确定西地那非对中等模拟海拔下肺动脉压力，心输出量，脉搏血氧饱和度和运动表现的影响。我们假设西地那非可通过抑制肺动脉压力的升高并引起心排血量和血氧饱和度的相对增加来减少缺氧时运动能力的下降。十二名受过耐力训练的男子在海平面进行了三项实验性自行车试验，并模拟了3,000m（F _I O ₂= 0.147），以双盲方式摄入安慰剂或西地那非50 mg胶囊后。每个测试包括一个预热期，一个处于峰值功率输出的60％的15分钟稳态期以及一个16.1 km的时间试验。所有受试者在缺氧状态下最大运动能力的下降幅度为6％至24％。这种下降与低氧最大运动中脉搏血氧饱和度的降低有关。西地那非对稳态运动期间测得的肺动脉压力，心输出量或脉搏血氧饱和度没有影响。在试验期间，西地那非对平均功率输出没有影响。在高强度循环运动中，急性，中度缺氧的肺动脉压不受西地那非的影响，并且似乎不影响心血管功能或运动表现。