Q1: My understanding is that we can acclimatise to altitude more easily the more times we go on an expedition. Is it true, and any recognised reading available?
Q2: I've read that we lose acclimatisation at the same rate we gained it.
"10 days after returning to sea level, we have lost 80 percent of our adaptations." http://www.elbrus.org/eng1/high_altitude1.htm
Whilst I felt that I have, is there any evidence of retaining an increased "base level" of acclimation for a long period?