Peru is famous for it’s impressive altitude; many of it’s most popular destinations sit at 8,000 feet above sea level. Cusco, the hub for many treks including the Classic Inca Trail, is 11,600 ft above sea level.Altitude sickness can begin to affect people at 6,500 feet above sea level. Symptoms will usually manifest after 6-10 hours of arrival and can take a day or two to subside.
The symptoms include a headache first, then you may experience a lack of appetite, nausea, or vomiting; fatigue; dizziness; light-headedness; and/or insomnia. Other symptoms include shortness of breath, rapid pulse, drowsiness, and swelling of the face, hands, or feet. Extreme altitude sickness can result in swelling of the brain and fluid accumulation in the lungs, which can be fatal. Keep in mind that these are extreme cases and not commonplace. The vast majority of folks feel lousy or suffer a headache for the first day or two at high altitude. Please refer to the section “What can I do about altitude sickness” for more information.