I spent a night in an altitude sickness clinic in Cusco on my way there! When we’d arrived (I was traveling with a large group for my friend’s wedding) we had some tours planned. They tell you not to hike, not to eat a big meal, and not to drink alcohol. So of course most of us did all three.

I’ve never had problems before even at similar altitudes, but my O2 sat got down to nearly 80 by the time I was put in the ambulance. It wasn’t pleasant.

But, a night hooked up to oxygen and I was fine. The hospital mostly catered to people with altitude sickness (even the locals get it, and it is seemingly random in who gets it and when) and was nicer than my hotel.

I got an ambulance ride there and a night in the hospital. They made me sign a waiver saying I agreed to pay it no matter the cost, and I was thinking about how many organs I’d have to sell to pay for it. Final price: $130. The place was cheaper and nicer than my hotel, and with decent meals and all the oxygen you can huff, so next time I’ll just book it.

Edit: one piece of advice. If you’re going to somewhere with that altitude, get a cheap pulse oxymeter on Amazon first! The hotels don’t have them.

We went to Machu Picchu around 10 years back, and as I'm slightly asthmatic I was a bit worried about the altitude sickness.

I'd read beforehand than coca leaves help prevent it, and made sure I drank lots of coca tea during our time there.

I don't know if it was the coca, but I barely felt the effects of altitude. We even went up the mountain beside the ruins (Huayna Picchu?), and it was no problem at all (at the time I was of medium build, but not particularly fit).

Cocoa tea tastes quite nice anyway, and the locals swear by the stuff - I recommend it.

I found that we were not affected by it at all, apart from occasionally out of nowhere just needing to take a really deep breath every now and then. This would be at really odd moments where I was not really exerting myself - e.g. sitting at the dinner table. We still drunk the cocotea etc though for the "authentic" experience! For what it was worth, we were not especially fit and a bit overweight at the time.

We spent a few days in Cuzco taking it easy to acclimatise. We were more worried about getting sick from taking showers or drinking local water than the altitude. There is some cool blockwork to see in Cuzco too (although it is quite a steep walk up to the citadel)

I visited in December 2017 and was worried about altitude sickness, but was quite rushed the days before the trip and didn’t have a chance to get sickness pills from my doctor.

I personally didn’t feel any symptoms, and neither did my friends. We’re all active and healthy people in their 20s.

The only real impact was reaching a shortness of breath much more quickly: hiking and such was certainly a lot more difficult than I’m used to at sea level. I had the same type of experience ski touring in Colorado; never really feeling satiated from breathing during vigorous activity.

The pass by Mt Salkantay was just over 15K ft at the highest point. I’d been training in Colorado so didn’t get sick, but definitely felt it! One person in our group did get a bit sick, our guide had him huff some kind of tincture. The coca candies/tea helped a bit as well.

Edit to add: the first day in Cuzco is pretty rough though, spent all day lounging and napping. It’s around 11K ft.

Wikipedia says Machu Pichu is only 2,400 meters / 7,900 feet altitude? That's not that high.

I mean, sure, try to acclimate somewhere if you're coming in from sea level, but much of Colorado is at that elevation, and the peaks are above 14,000 feet. Traveling to ski at Telluride is more elevation.

The only thing that made me sick was the anti-altitude medication. That stuff is nasty.

Oh, sure, I got exhausted crossing the Dead Woman's Pass but considering I had just walked up the side of a mountain, that's not so surprising. A week in Arequipa and a week in Cusco before trekking to Machu Picchu is enough to acclimatize your body. If you fly in and take the tourist bus to the snapchat opportunity, things might be different.

One thing I'll assert is that a couple of weeks later I ran my best ever time in a road race.

For anyone contemplating going, it’s worth visiting a doctor for a script to get acetazolamide (trade name Diamox). Heed the advice to eat very little and avoid/reduce alcohol. The number of people we saw ruin their holiday for the sake of a big meal and a couple of beers.

https://en.m.wikipedia.org/wiki/Acetazolamide

On Salkantay (which can be a luxury trip, the facilities are first-rate), you start at Cuzco for a day or two which is a higher elevation than MP. But the pass is ~15k, which takes a few days to hike to on the trail.

Getting over the pass was still a major chore for many in our group. The last 1k uphill was walking 100' and taking a minute break. People who raced up or down got sick.

I didn't, but by the time I visited Machu Picchu I had already spent a couple of weeks at altitude, including climbing a 6,000 m summit.

Altitude sickness is a weird one, I'm a smoker and don't exercise, yet I was affected less than my friends who were all non-smokers and exercise regularly.