Research by scientists at the Stanford University and the Veterans Affairs Palo Alto Health Care System on participants who were riding stationary bicycles while breathing through masks to simulate the high altitude low-oxygen conditions at 12,700 feet was found to have improved its six kilometers timing by an average of 39% following consumption of Viagra. The erectile dysfunction drug is now being considered by military researchers to help soldiers function better at high altitudes.
As lead author, Anne Friedlander, said, 'It provides a pretty clear advantage to some people.' The research appears in the current issue of the Journal of Applied Physiology.
Viagra (chemical name, sildenafil) causes blood vessels in the penis and lungs to relax. In 1998 it won federal approval as the first erectile dysfunction pill. Last year drug maker Pfizer Inc.
won approval for Viagra, under the new name Revatio, to treat pulmonary hypertension, following which rose its potential as a high altitude performance drug.
Pulmonary hypertension is often a result of exercise in oxygen-poor environments. As blood vessels constrict in the lungs, the heart has to work harder to pump blood through the body.
The research measured the performance of 10 trained cyclists. Each cyclist was tested on a stationary bike at a simulated altitude of 12,700 feet, involving a six-kilometer ride. Placebo of 50-milligram dose of Viagra and a 100-milligram dose was also used.
It was found that the drug responders demonstrated significant improvements in their times with the 50-milligram dose. Their average time was 10 minutes, 48 seconds, compared to 15 minutes when they took a placebo. Increased dose of Viagra did not increase the benefit.
The researchers found that the other six riders did not show any enhanced performance. While the researchers are yet uncertain as to why only four riders responded to Viagra, they observed that these were also the few whose times suffered most at high altitude with only a placebo. Viagra seemed to allow them to make up for lost performance.
Military researchers, will probably initiate testing Viagra's effects on about a dozen soldiers at a military laboratory on Colorado's Pikes Peak, elevation 14,110 this summer according to Charles Fulco, a research physiologist and high-altitude expert at the U.S. Army Research Institute of Environmental Medicine in Natick, Mass.
"If we send a group of guys into the mountains of Afghanistan, they need to be able to deal with the altitude," Fulco said.