A few weeks ago now there was an article in the Daily Mail about some scientists from a Belfast University who had done some research on lack of oxygen in pax (not pilots!) whilst flying and had found that levels in the blood drop from 97% before flight to 93% at altitude. If this same thing happened to a patient in hospital (who wasn't flying!) they would immediately be given 'extra oxygen'.
Perhaps there is a problem with low O2 and being gassed and that the former problem is the real culprit.
Anybody got a link to that study as I think it's probably relavent.
Just thinking.
Wow! I've been in the low 90% several times without the need for O2. In fact I can't recall any feeling of unwell. Now being in the 80's is a bit more concerning.