Altitude sickness

Before you set off on a climbing, or trekking, expedition, make sure that you are aware of the risks, symptoms, and treatments for altitude sickness.

Be aware that if you are travelling to a remote part of the world, it may be difficult to get medical care of the same standard as in the UK.

Acclimatisation

Proper acclimatisation is the best way to prevent altitude sickness. Acclimatising, by ascending slowly, will give your body sufficient time to adapt to the change in altitude.

Before booking your trip, you should make sure that there is enough acclimatisation time built into the itinerary to ensure that you are not putting yourself at unnecessary risk of developing altitude sickness.

Sleep at a lower altitude

Once you are above 3,000m (10,000ft)  do not increase your sleeping altitude by more than 300m a night. You can go up higher during the day, but each night you should go back down to a camp that is no more than 300m higher than the previous night's camp.

However, if it is not possible to follow this formula, some travel companies include a day’s rest in the itinerary, with a walk down the mountain in order to help you to acclimatise.

Some holidays offer to climb a mountain, such as Mont Blanc, in a week. However, this ascent rate can result in altitude sickness. It would be better to do it at the end of a two week long holiday after acclimatising by climbing a few lower peaks first.

Medication

As well as being used to treat altitude sickness, acetazolamide (Diamox) and dexamethasone can also be used to help prevent the onset of symptoms.

Acetazolamide

For prevention purposes, the recommended dose of acetazolamide is 125-250mg, twice a day. You should begin taking the medication 1-2 days before starting to ascend, and continue taking it while you are ascending, and for three days after you have reached your highest altitude.

See the ‘treatment’ section for more information about acetazolamide.

Dexamethasone

For prevention purposes, the recommended dose of the steroid, dexamethasone, is 4mg twice a day. The medication is usually taken for about two days, starting from when you begin your ascent. It should help prevent the symptoms of altitude sickness developing.

See the ‘treatment’ section for more information about dexamethasone.

Other preventative advice

As well as acclimatising properly and taking prescription medication, the advice listed below will be useful in helping you to avoid getting altitude sickness.

• If you start to develop the symptoms of moderate altitude sickness (see ‘symptoms’ section), stay at your current altitude until your symptoms improve.
• If your symptoms get worse, immediately go down from your current altitude.
• As different people acclimatise at different rates, make sure that everyone you are travelling with has fully acclimatised before you go any higher.
• Make sure that you keep well hydrated by drinking plenty of fluids (a minimum of 4-6 litres a day).
• While at altitude, eat a high calorie diet.
• Avoid smoking, drinking alcohol, and using medication, such as tranquillisers and sleeping pills while you are at altitude, as they could make any symptoms of altitude sickness worse. Consult your GP if you are unsure.

See the ‘useful links’ section for more advice about how to prevent altitude sickness.