Admittedly, it is a unique experience to enjoy a sunrise in the freedom of the mountains. But many underestimate the risk of altitude sickness. Because mountain air is different. At natural altitude, the air pressure decreases with each meter of altitude, and with it the oxygen available to our bodies. At an altitude of 5000 m, the available oxygen is only about 11%. This is almost half of what we have in the lowlands (20.9%). Already from 2500 m above sea level the efficiency is reduced and according to studies already 10% suffer from mild forms of altitude sickness at this altitude. From 5000 m above sea level, it is already more than 90%!