( Sildenafil (Viagra) significantly impro...)Viagra improves high altitude exercise performance up to 45% for some

Ten cyclists who took sildenafil at altitude collectively lowered the time it took to cover six kilometers by 15% compared to placebo trials at altitude. The cyclists also significantly improved stroke volume (the volume of blood moved out of one ventricle of the heart per beat) and cardiac output (stroke volume times heart rate) compared to the placebo trial. Sildenafil also minimized the decline of arterial oxygen saturation of the arteries when the cyclists were at simulated altitude of 12,700 feet.

But the researchers discovered that these improvements occurred largely because some people achieve major gains with sildenafil at altitude while others improve much less or not at all. The responders improved 39% in the time trial performance at altitude compared to their performance at altitude with a placebo. Some in the responder group improved as much as 45%, according to a study in the Journal of Applied Physiology published by The American Physiological Society. Non-responders improved an insignificant 1%.

The study, "Sildenafil improves cardiac output and exercise performance during acute hypoxia but not normoxia," by Andrew R. Hsu, Kimberly E. Barnholt, and Nicolas K. Grundmann, Veterans Affairs Palo Alto Health Care System; Joseph H. Lin and Stewart W. McCallum, Stanford University Medical Center; and Anne L. Friedlander, Veterans Affairs Palo Alto Health Care System and Stanford University appears in the June issue of the Journal of Applied Physiology.

Drug expands the blood vessels
Sildenafil citrate is best known as Viagra, a drug used to treat erectile dysfunction. The drug was originally developed to relieve high blood press
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Source:American Physiological Society