Reading this thread, I was reminded of something I’ve always wondered about, people used to low altitudes require a fair bit of time to acclimate to higher altitudes, is there a consequence to doing the reverse? If you’re born in Nepal, do you suffer after a plane ride to the nearest coast?
I’ve never heard of such a thing. But I have heard that some athletes spent a lot of time at high altitude because their bodies make some adjustments and they perform better (for a while) when they return to low altitude.
No major cosequences. Someone moving to sea level may have greater stamina, but that wouldn’t be an issue unless their an athlete.
FWIW (and honestly it’s probably not worth much), when I flew from St. Louis (elevation ~600ft) to Denver (elevation ~5000ft), I thought for a few minutes while at the Denver airport that I was going to pass out. About an hour later I was on a flight to Sacramento (elevation ~100ft), and as God is my witness, I felt like the sky was closing in on me those first fifteen or so minutes on the ground in Sacramento. Probably all psychosomatic, but there it is.
The main adaptation to higher altitudes is more red blood cells. Hence the interesting shenanigans that endurance athletes get into. It creates a natural blood doping. The downside seems to be a higher risk of some cardiovascular issues due to the higher blood viscosity (which we may assume is the reason we stick with a thinner blood at lower altitudes.)
Some native Tibetans have reported they can detect a difference at sea level, describing lower altitude air as feeling thick or uncomfortable, but it doesn’t seem to impair their abilities to function.
I’ve experienced both: returning to Munich (elevation ca. 500 m) after 10 months in Colorado (elevation 1 500 m), I did feel more stamina.
But when going from Munich to North-Rhine-Westfalia (elevation ca. 40 m), the air does feel thicker, and I get much more tired.