Machu Pichu is high altitude, but when we visited it some years ago we found out that Cusco is even higher. Had a terrible altitude headache for a day until we went down in altitude by train to Machu Pichu.
My first night in Cusco I ate a big steak and got sick as a dog for the next 12 hours... it was miserable!
I had spent the week prior camping in the Amazon, near Iquitos... so who knows, it could have been a combination of the altitude change and the temperature change.
I live at 8,500 ft elevation, but French alps have a lower tree line due to being farther north.
Anything higher than 7000 feet above sea level makes my heart pound like it is coming out of my chest. I’ll never go to the mountains again, I am a low lander. My home is 50 feet. My husband falls asleep at high elevations, I can’t fall asleep.