Altitude and Acclimatisation

Acute Mountain Sickness (AMS) is a non-fatal but unpleasant condition, typically of headache, nausea, poor appetite, dizziness, poor sleep and overall malaise.   It is rare below 2,500-metres but common above 3,000-metres, especially when people go too high, too quickly or ignore symptoms.

We aim to reduce AMS by ascending slowly, especially on those trips that attract people who have not been to high altitude before.  This might not work for everyone in the time available for the trip and, in some places, big height gains are forced by the topography or by the location of campsites/ lodges or water.  When appropriate and where practicable, we add extra days for acclimatisation and take a rest before or after any big ascents. 

We publish acclimatisation profiles and risk assessments for most trips on our website, showing daily altitude gains.  At the pre-trip weekend, you learn about AMS; prevention, recognition and treatment.

Diamox is a drug that lessens AMS symptoms and assists acclimatisation. It does not mask symptoms (unlike other drugs that may be used to treat more severe forms of altitude illness).

Diamox can have unpleasant side-effects. Some people might be allergic to it. If you are considering taking it, based on previous poor acclimatisation or on the altitude profile of the trip, please consult your GP. You and your GP may find this article useful.