The hostile slopes of Mt. Everest have given scientists some clues about the problems faced by the victims of lung disease.
Researchers have finished poring over the results of experiments conducted on the world's tallest mountain in 1981 and have published their conclusions in various scientific journals, including Science magazine.
"We now know a great deal more about the way oxygen deprivation affects man and how man adapts to it," said John B. West, a respiratory specialist at the University of California, San Diego.
"We wanted to find out how far you can push the human body," West said. "The most surprising thing we found is the extent the body can adapt. There are very dramatic changes."
West said the thin air of Everest increased breathing rates up to six times normal, changed the thickness of blood, impaired kidney functions and reduced the body's ability to digest food and absorb water.
Brain functions, including memory, coordination and common sense, were reduced at high altitudes, West said.
Victims of serious lung diseases--such as emphysema and chronic bronchitis--may have to deal every day with the lack of air experienced by the team on Everest.
The increased respiration rate triggered several changes in the climbers, including an increase in the number of red blood cells that carry oxygen.
"Although the blood can carry more oxygen," West said, "it thickens the blood and makes it more difficult to pump round the body."
West was part of the 1981 American Medical Research Expedition to the mountain that included 14 scientists and six mountaineers.
The expedition employed 40 Tibetan Sherpas to lug 3,500 pounds of supplies and scientific gear to the 20,700-foot level. West helped man the mountainside laboratory while two Sherpas and three Americans continued to the top of the 29,028-foot peak.