London, Aug 12 - 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.