Hiking on the Inca Trail is a wonderful experience. Realize that Cuzco the Inca capitol and closest airport, is well over 12,000 feet. The trail goes up from there. It takes quite awhile to acclimate even with coca leaf tea.

If you can travel in the mountains for a week before starting your hiking adventure you will be way ahead. After 3 weeks in the Andes I felt totally normal in LaPaz, Bolivia at almost 13,000 feet.