Comment by kelnos

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.