I did the Inca Trek to Machu Picchu a few years ago. Spending a couple of days in Cuzco to acclimate was crucial. So definitely give yourself a few days there (or in a similar city). Also, I echo the comments about the coca leaves. They come in tea form and in candy form and they were super helpful. I wasn't sick at all--except after I drank the thimble of pisco sour from our trek cooks to celebrate before we reached the summit. So stay away from alcohol! 🙂 Peru is beautiful as are the Andes Mountains. I'm excited about your trip. Best wishes! ... View more

@REI-AliciaS I purposely drink a lot of water on long flights, which makes me get up to use the bathroom. That way, it ensures I get some circulation and movement. Also, every four or so hours, I get up and walk to the back of the plane and do a little stretching (reach down to touch my toes and hang for a few; air squats; pulling my arms across my chest to stretch my shoulders). I don't have any good sleep ideas so I'm interested to read suggestions from others! ... View more