Quoted By:
Wikipedia says 6-10k ft...
Two big things... acclimation and hydration.
Avoid alcohol, that can worsen the effects of altitude.
If you're in reasonably good shape, getting up to 5-6k and taking it easy for a day is usually adequate. You're not going to have a huge enough elevation change in a day of hiking to need to acclimate much more than that. Just take it easy the first day or two.
Other thing is hydration... drink water, and a lot of it. You should be pissing several times a day. Dehydration and elevation can make for a really shitty day.
Did a photo shoot a few years ago.
Camera crew was from Chicago, and had just flown out here from another shoot in Atlanta.
I took them up to a mountain pass at 14k+ ft the next day... several of the crew got to experience first-hand what elevation sickness felt like.
Sat them down, told them to relax by the trucks and drink some water (glad I threw the case of bottled water in my truck that morning), reassured them that we had things covered and told them to let me know if they started feeling any worse.
Went down in elevation to ~11k ft, they started feeling a little better, found a spot to set up and shoot, got the photos that landed me on billboards, and by the time we got back into town for lunch (~9k ft) they were all feeling a lot better.
Pic very much related. That was an interesting day showing city slickers around innamountains. "What do you mean cell phones don't work out here?"
