Reading the altitude

San Pedro sits at 2,400 metres, which sounds modest until you notice you are out of breath tying a shoe. The high excursions go to 4,300 and above. The gap between those two numbers is the whole design problem of an Atacama week.

So the first two days are deliberately unimpressive. A low valley, a short walk, an early night. Guests sometimes tell us, politely, that they could do more. They could. They would also spend the fourth day in a room with a headache, and the fourth day is the one with the lagoons.

The rules we actually enforce: no alcohol on the first night, water past the point of thirst, and every high morning starts before six so that we are back down by noon.

Altitude is not a fitness test and it does not respect training. The fittest person in the group is as likely to feel it as anyone else — often more so, because they push through the early signal instead of mentioning it.

Mention it. The guide carries oxygen and a pulse oximeter and has driven someone down at two in the morning more than once. Nobody has ever been made to feel dramatic for saying they felt off.