I've been to Machu Picchu three times now, and each time I notice how challenging it is for visitors to adapt to the high altitude on the Inca Trail. Last year I met a group of travelers who had to turn back because they were feeling really unwell - it was pretty sad to see them having to leave. I've learned a thing or two about acclimatizing and avoiding altitude sickness, so maybe some of you can benefit from my experience.
