The main problem you might encounter in Cusco is because of the altitude. However, in Machu Picchu you will be at a lower altitude. In general, we recommend:
To drink coca- leave infusions (mate de coca) upon arriving in Cusco. Every public place and hotel have some and even some hotels give it to customers for free.
To drink a lot of water during the excursion.
Tap water in most of Peru is potable, but the chemical and bacteriological content varies from place to place. However, to avoid problems, we recommend you to always drink bottled water.
If you smoke, try to slow down a little bit.
If you feel sick, tell your guide immediately. He is well trained and will be able to help you or to take the necessary measures.
What to bring
Camera.
Boots, tennis shoes or walking shoes with no heels.
A hat or cap.
Rain wear for the rainy season.
Insect repellent.
Sun screen Lotion.
Sun glasses.
A sweaters or a jacket.
A Swimsuit for the hot springs in Aguas Calientes.
