London, Aug 12 (Inditop.com) Taking dexamathasone, popularly known as dex, may improve exercise capacity in some climbers, according to Swiss researchers.
Dexamathasone has been used for years to treat altitude-related symptoms in climbers, 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),” said study co-authors Manuel Fischler and Hans-Peter Brunner-La Rocca of the University Hospital Zurich and University Hospital Basel, both in Switzerland.
“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,” they added.
The researchers recruited 23 mountaineers with a history of HAPE and administered baseline cardiopulmonary exercise tests at low elevation (490 metres, or 1,607 feet).
Subjects were tested for oxygen uptake by pedalling a stationary bike at a constant rate for six minutes, and then for exercise capacity by pedalling 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 Fischler.
All participants were randomized to take either tadalifil, dexamethasone or a placebo, beginning the day before a cable-car ascent from Alagna, Italy, at 1,100 metres (3,609 feet), to 3,200 metres (10,499 feet).
They then ascended on foot to Capanna Gnifetti at 3,650 metres (11,975 feet). After an overnight stay at Capanna Gnifetti, the climbers finally ascended to Capanna Regina Margherita at 4,559 metres (14,957 feet).
A second round of cardiopulmonary exercise tests were performed 4-5 hours after arrival, and echocardiographic examinations were performed the next day.
“Reduced oxygen content in the air is the major limiting factor at high altitude. Reduction in exercise capacity goes in parallel to the reduction in oxygen up to an altitude of approximately 4,000 metres, said Fischler.
The results are slated for publication in the Aug 15 issue of the American Journal of Respiratory and Critical Care Medicine.
