What’s the best acclimatization strategy before trekking the Inca Trail to Machu Picchu?

Spend at least two nights in Cusco (3,400 m) or the Sacred Valley before starting the trek, hydrating well and avoiding alcohol. Consider taking acetazolamide (Diamox) after consulting a doctor, and walk slowly on the first day, allowing your body to adjust. If you develop severe headache or nausea, descend immediately.