On Aug 16, 5:20 am, wrote:
Boeing funded a clinical trial to actually determine the effects of
being at an 8000 foot altitude for extended periods, and the results
were published last year in the New England Journal of Medicine. It's
an interesting read: here's the URL Many peer reviewed journal
articles require membership in an appropriate group (usually involving
fees) to be read: this one is freely available.,

http://content.nejm.org/cgi/content/abstract/357/1/18

For what it's worth, the number of subjects involved, and the
inclusion/exclusion criteria were fairly limited ( a couple of
hundred people, not nearly enough to uncover rare but important
conditions that could impact health) but the population probably is
representative of those holding Class III medicals or better. It's
fair to say nothing surprising was uncovered, except to learn that
such a study had not been done long ago.

It reminds me of the old adage that we should drink 8 glasses of water
a day. That's something that has actually been debunked in a recent
study.

Of the gazillion times I've flown, once I had a
problem equalizing ear drum pressure, that was
quite uncomfortable. I guess the *rate of change*
of barometrics is a subjective unknown, as it does
require a rate of adaptation.
Ken