> Bodies acclimate.

Absolutely -- and at different rates.

I have had severe asthma since puberty. After a decade of suffering, good drugs arrived around the turn of the century, and I've been well controlled since and I've been pretty active.

But I am better at altitude. I have narrow obstructed tubes in my lungs. Thinner air flows through them more easily. The higher I am (on land, obviously) the more easily and efficiently I can breathe.

In the old days, asthma clinics were located up mountains for this reason.

I like spending time at altitude. Thinner air means more oxygen for me, which means I feel better and can be more active.

If I could live 3-4 km up all the time, without vast expense in somewhere tiny, I would.