Taking dexamathasone prophlyactically may improve exercise capacity in some mountaineers, according to Swiss researchers. Dexamathasone, known popularly to climbers as "dex," has been used for years to treat altitude-related symptoms in mountaineers, but has never been tested for its ability to improve exercise capacity at high altitude.
"We have known that both tadalafil and dexamethasone are good for preventing high altitude pulmonary edema (HAPE) and dex for treating symptoms of acute mountain sickness (AMS). But we did not know whether they could also improve exercise capacity at altitude by reducing pulmonary hypertension, one of the important factors in altitude- related exercise limitations," said lead authors Manuel Fischler, MD, of the University Hospital in Zurich, Switzerland, and Hans-Peter Brunner-La Rocca, of the University Hospital in Basel, Switzerland.
The results were published in the August 15th issue of the American Journal of Respiratory and Critical Care Medicine, the journal of the American Thoracic Society.
The researchers recruited 23 mountaineers with a history of HAPE and administered baseline cardiopulmonary exercise tests a low elevation (490 meters, or 1607 feet). Subjects were tested for oxygen uptake kinetics by pedaling a stationary bike at a constant rate for six minutes, and then for exercise capacity by pedaling at 50 percent of their predicted maximum workload for one minute, then increasing output by 25 percent each additional minute until exhaustion, usually after 8 to 12 minutes.
"At low altitude, peak exercise performance of subjects was significantly above age- and gender-adjusted normal values, indicating superior fitness in these subjects," noted Dr. Fischler.
All participants were randomized to take either tadalifil, dexamethasone or placebo, beginning the day before a cable-car ascent from Alagna, Italy, at 1,100 meters (3,609 feet), to 3,200 meters (10,499
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American Thoracic Society