So, yesterday I went with jbarros and Travis up Throop Peak from Islap Saddle in the Angeles Forest. 9138′ above sea level and a 12 mile round trip from Travis’ truck (which was around 6100′ above sea level, IIRC). I discovered that I have altitude issues above 8000′ or so, and am pretty much useless above 9000′.
The last two hundred feet took like an hour and a half, as I staggered slowly up the hill, collapsing in the shade of each tree I reached for a few minutes of determined breathing and attempting to rid myself of breakfast.
Once I reached the top, I was beyond all ability to function. I managed most of a cup of tea and a couple small chunks of bread with hummus, but it was work… So, they packed up quickly and we made it back down that 200′ in 15 minutes and I was already feeling much better.