[superfries]

Nobody is lasting more than 6-7 minutes without supplemental O2 at 25k feet.

[Inyo-Mono]

Nobody is lasting more than 6-7 minutes without supplemental O2 at 25k feet.

As was said by liege in post 13 "People climb Mt. Everest without supplemental oxygen. Not very many, but it occurs." It is very rare but Reinhold Messner climbed Everst in 1978 without oxygen. Everest is 29,029 feet.

[Mom MD]

Tell that to the people who climb Everest without supplemental oxygen.

[CodeToad]

"Nobody is lasting more than 6-7 minutes without supplemental O2 at 25k feet."

Wanna bet? It's done every day at the various Air Force hyperbaric chambers. Been there a few times myself.