Eli5: what does airplane cabins pressurized to 8,000 ft mean and how does that not feel like breathing at high altitude?

Question

People will visit Denver or New Mexico and feel the altitude at only 6,000 feet or so. They’ll get winded or headaches or other issues till they adjust after a few days.

So how come we breathe without issue on planes if they’re pressurized to 8,000 feet?

In: 11

Answer 1

There are couple of reasons reasons. One is partial pressures, while the cabin is pressurized to 8000ft the amount of O2 is different (higher) than it would be on a mountain at 8000ft. Second is the amount of physical activity in a plane v. outside in those areas, so you are less likely to have the physical demand in a airplane v. the real world.