[Hojczyk]

Alititude sickness is nothing to fool around with

Worked in Telluride Colorado at 9,500 and went fishing at 11,000 and it was like I had no lungs left.....

[MtnClimber]

Altitude sickness on Long's Peak is common. I have climbed Long's peak and can see it from my living room window. I have had friends that wanted to climb Long's Peak, but they all got altitude sickness. just above tree line. Here is Keiners Route which they were climbing, the Red is Keiners and blue is the normal descent route:

The highest peak I have climbed was Cerro Aconcagua in the Andes Mountains which is just under 23,000 ft altitude. It has only about 1 month climbing season and the year I climbed it about 7 people died from altitude sickness.