In reply to chasm: There is a trip being undertaken to Everest Base Camp next year which will be accompanied by medics studying high altitude body function. The participants, who are all paying the full cost of their trip, will have lung function studied every day with the help of exercise bikes.
One of my cycling friends (who is very fit but has never been higher than 3000 metres) is going on this trip, and the oldest participant is an 85 year old man. The idea is to gather information on how a variety of people react to exercise at altitude.