Machu Picchu sits at 2,430 metres (7,970 feet) — well below the altitude threshold where most people get sick, but still high enough to notice on the stairs if you’ve just flown in from sea level.
Cusco, where most travelers arrive first, is the bigger problem: at 3,400 metres (11,155 feet) it’s roughly 1,000 metres higher than the citadel. Spending two to three days in Cusco or the lower Sacred Valley before heading up has two benefits — you acclimatise, and when you reach Machu Picchu it actually feels like coming down.
Mild altitude symptoms (headache, light nausea, broken sleep) are common and resolve within 48 hours. Drink more water than you think you need, go easy on alcohol the first night, and if you want pharmaceutical help, acetazolamide — prescribed in advance — is the standard preventative.
Once at the ruins, the stairs and the sun do most of the work; take breaks on the terraces as needed.
For transfers and tickets that bake in acclimatisation time, see Peruways.
