Another indication for "the little blue pill"?
Jun 30, 2007 11: 14 EST
Recently published data from Belgian researchers lends more weight to the work that's been coming in over the past few years: Viagra isn't just for bedtime anymore. We've long been aware that sildenafil (popularly known by its trade name Viagra) is a potent pulmonary artery vasodilator, making it very useful for prevention and treatment of HAPE. But these researchers conclude that it can be useful to improve exercise performance in the otherwise well -- read on in this abstract:
The phosphodiesterase-5 inhibitor sildenafil has been reported to improve hypoxic exercise capacity, but the mechanisms accounting for this observation remain incompletely understood. Sixteen healthy subjects were included in a randomized, double-blind, placebo-controlled, cross-over study on the effects of 50-mg sildenafil on echocardiographic indexes of the pulmonary circulation and on cardiopulmonary cycle exercise in normoxia, in acute normobaric hypoxia (fraction of inspired O2 , 0.1), and then again after 2 weeks of acclimatization at 5000 m on Mount Chimborazo (Ecuador). In normoxia, sildenafil had no effect on maximum VO2 or O2 saturation. In acute hypoxia, sildenafil increased maximum VO2from 27 ± 5 to 32 ± 6 mL/min/kg and O2 saturation from 62% ± 6% to 68% ± 9%. In chronic hypoxia, sildenafil did not affect maximum VO2 or O2 saturation. Resting mean pulmonary artery pressure increased from 16 ± 3 mmHg in normoxia to 28 ± 5 mmHg in normobaric hypoxia and 32 ± 6 mmHg in hypobaric hypoxia. Sildenafil decreased pulmonary vascular resistance by 30% to 50% in these different conditions. We conclude that sildenafil increases exercise capacity in acute normobaric hypoxia and that this is explained by improved arterial oxygenation, rather than by a decrease in right ventricular afterload.
To read the entire article:
Vitalie Faoro, et al.
Effects of Sildenafil on Exercise Capacity in Hypoxic Normal Subjects. High Altitude Medicine & Biology
Jun 2007, Vol. 8, No. 2 : 155 -163
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