8,000 ft (2,400 meters) isn't particularly high. Millions of people live at that altitude. It's extremely common for people to go on a skiing vacation at that altitude or above, up to maybe 4,000 meters, and not need to take any particular precautions.

As to comments here about days resting while progressing to higher altitudes, such as in the Himalayas. A day or two will mostly result in adjustments in the water balance of your blood. It takes about 10 days to two weeks for your bone marrow to start producing additional red blood cells to compensate for the lower level of oxygen in the air.

High level altitude sickness is more complex and relates to multiple factors, including fluid balance, the health of one's vasculature and lungs, etc.

It is certainly the case that populations that have lived at high altitudes in the Himalayas or Andes for thousands of years have evolved adaptations that make such living easier.

Yeah, I spend a decent amount of time during the year at 6500-7000 feet (and live at sea level for the rest of the year). There's always an acclimation period when I first get there, but it's nowhere near as severe as the article suggests. I'm fine going right to the gym or whatever when I get there; I don't need a few days of rest first. In the winter I'll spend hours of the day up at 8000-9000 feet, and yes, I get winded easier, but I'm otherwise fine. I'm in my 40s, so while I'm not old, I'm not young either.

I think the highest up I've ever been for any solid amount of time was 10,500 feet, and sure, I could tell the difference, but it wasn't debilitating or anything remotely like that, and I could do moderate-plus physical activity without anything bad happening.

I've also been up to 15,000 feet (Salkantay Pass in Peru) for a very short time, and definitely felt it. A few people in my hiking group had to take some medicine, and one or two availed themselves of camels. But I would also consider this hike a high-exertion activity; they were fine when we took a break for a while and relaxed.

But I'm just not convinced that most (generally healthy!) people need that much acclimation before doing day-to-day tasks, including regular levels of exercise.

> Millions of people live at that altitude

Millions isn’t that many people :)