Sildenafil Has Little Influence on Cardiovascular Hemodynamics or 6-km Time Trial Performance in Trained Men and Women at Simulated High Altitude

Abstract

In this group of endurance trained men and women, sildenafil had very little influence on cardiovascular hemodynamics, SaO2, and 6-km time-trial performance at a simulated altitude of ∼3900 m. It appears that a very small percentage of endurance-trained men and women derive meaningful improvements in aerobic performance from sildenafil at a simulated altitude of ∼3900 m.

Exercise Training Plus Sildenafil Treatment: Role on Autonomic and Inflammatory Markers

“…Although sildenafil has not been included in the World Anti-Doping Agency's list of prohibited substances, it is known that this drug has been used by amateur and high-performance athletes as an ergogenic resource to improve exercise performance [35]. The plau-sibility besides its theory is based on the capacity of sildenafil, during pulmonary hypoxia, to induce pulmonary vasodilation, reducing pulmonary arterial pressure and hypoxic vasoconstriction, which is real factor limiting oxygen uptake, since pulmonary vasoconstriction reduces blood transit time in the lung capillary network, causing lower arterial oxygen saturations [19,20,24,32,38]. However, at normoxic conditions, the benefits of pulmonary vasodilation induced by sildenafil are not clear, since usually oxygen diffusion at the alveolar barrier is not a severe limiting process.…”

Can sildenafil improve physical performance at altitude? Current scientific evidence

“…However, data are not categorical, both at rest and during exercise. The arterial blood pressure (systolic, diastolic and mean) 1,18,29,31,32 and systolic volume 18,31,32 were almost not affected. Lung function parameters (ventilation, tidal volume, respiratory rate and respiratory exchange ratio) were unaffected by the drug 14,15,18,30 .…”

“…Lung function parameters (ventilation, tidal volume, respiratory rate and respiratory exchange ratio) were unaffected by the drug 14,15,18,30 . Finally, the exercise values such as W peak 1,14,15,18,29,31,32 or VO 2max 14,29 are not conclusive at all to affirm that sildenafil significantly improves performance during exposure to acute hypoxia, regardless its normobaric or hypobaric nature.…”

“…The conclusions were that sildenafil had little or no influence on the supply of oxygen at rest or during exercise since it did not improve the SaO 2 , CO, W peak nor time-trial performance in men and women neither at moderate or high altitude. These authors concluded that the magnitude of sildenafil effects could be determined by the geographical altitude and the subsequent degree of hypoxia, thus proposing that the potential beneficial effects of sildenafil during exercise are unlikely to be obtained at altitudes less than 4000 m. Jacobs et al 32 studied 35 trained subjects (20 men and 15 women, cyclists and triathletes) that performed a W peak test at SL and another in simulated HA (12.8% FiO 2 or 3900 m). Later, they performed three experimental exercise tests (30 min at 55% of altitude-specific capacity + 6 km time-trial) one at SL and two experimental exercise tests at simulated HA after ingestion of either placebo or 50 mg sildenafil with at least 48 h between the tests.…”

Acute Mountain Sickness Prophylaxis

“…There is evidence that sildenafil improves maximal exercise capacity at high altitudes (14,435Y19,028 ft), yet these effects diminish as elevation decreases until no benefit is seen at approximately 13,123 ft or less (9,12,14). Again, while this additional effect may seem attractive as adjunct therapy, the adverse effect profile of PDE-5 inhibitors may limit their practical application.…”