Jay, do a test... Borrow a portable bottle from someone... Go out at night
and fly around for 45 minutes at 8500 not using the O2... Then, turn it on
and while looking right at some lights of the ground put the cannula in
your
nose and take a half dozen good sniffs... Unless you are an olympic
caliber
triathelete, you are in for an experience...

I presume the lights get brighter/clearer?

I have noticed that we tend to get more tired when flying at those
altitudes, (kinda nice when the kids nod off!) but I haven't been able to
detect any other side effects. We do keep an eye on our fingernails, and
try to watch each other for signs of hypoxia, but to date haven't seen any.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"