"Arquebus257WeaMag" wrote in message
m...
Im just wondering why pure oxygen is used for high altitude flying
instead of regular air. I thought prolonged exposures to breathing
pure oxygen can be harmfull as you can become oxygen dependant.

http://www.batnet.com/mfwright/hypoxia.html
Hypoxia

Hypoxia is a state of oxygen deficiency in the body which is sufficient to
cause an impairment of function. Hypoxia is caused by the reduction in
partial pressure of oxygen, inadequate oxygen transport, or the inability of
the tissues to use oxygen.

In brief, being drunk is kind of the same as being exposed to high altitude.
In both cases, oxygen to your brain and muscles is reduced.