Less oxygen in the air is what causes problems with sleep at high altitudes. In most cases, if your acclimatization transition is going well, you won’t have any issues with your sleep at night. In other words, following the golden rules of high-altitude acclimatization will make your sleep better. Here is a recap of them: Hike slowly! Ideally, your pace should be two times slower than normal walking pace. Choose longer routes. 7-day climbs through Lemosho, Machame and Rongai are enough for most hikers. Do not ignore acclimatization hikes. Following the “go high, sleep low” principle will help your acclimatization. If, however, you have a headache at night or it is difficult to fall asleep, make sure to tell your guide and he will give you the necessary pills.