When the body slowly adapts to lower oxygen levels the process is called acclimatisation.
Different people acclimatise at different speeds, so no rule works for everyone, but there are good guidelines.
Over 3,000m go up slowly, sleeping no more than 300m higher at the end of each day. Going higher during the day is ok as long as you go down to sleep (“walk high – sleep low”). If you go up higher and can’t descend – take a rest day to allow your body time to ‘catch up’.
This may seem very slow, and some people will comfortably be able to go up much faster, but in a group someone will always be the slowest to acclimatise – and the timetable should be made to keep them healthy. A rest day scheduled after every 2 to 3 days will also help.
Driving or flying to high altitude means more people will suffer from AMS.
It is really sensible to find out about the height of your planned route before you travel. Better still, make a drawing to show the height that you will sleep at each night. If you don’t know – ask. There’s no better way to spot the days which are likely to cause altitude illness.
