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Altitude Sickness

Dr Roger Henderson
Reviewed by Roger HendersonReviewed on 29.04.2024 | 3 minutes read

Altitude sickness is also known as acute mountain sickness and can happen to anyone, no matter what your fitness level, age or experience of climbing is. It affects your breathing and your ability to take in oxygen. This can be life-threatening. It happens when you travel to a higher altitude too quickly, typically greater than 2,500m above sea level, often when mountain climbing but also if travelling to cities that are high above sea level. (It isn’t possible to get altitude sickness in the UK because no mountain in the country is anywhere near 2,500m above sea level).

What are the symptoms of altitude sickness?

Symptoms usually develop within 6 to 24 hours of reaching the 2,500m altitude level and initially feel like a bad hangover so you may feel a gradual headache starting as well as feeling sick, dizzy, tired and disoriented. You may also find it difficult to breathe and feel short of breath, and the symptoms are often worse at night. Remember that if you feel unwell, it is altitude sickness until proven otherwise.

Can I prevent altitude sickness?

Of course, avoiding travelling to altitudes of 2500m above sea level is one way of preventing altitude sickness. But if you can't avoid it, it's important that you don’t go directly to these levels but go slowly (500m at a time) over 24 to 48 hours to allow your body time to adjust. Drink plenty of water throughout your journey and avoid strenuous exercise. Be sure to incorporate time for an appropriate amount of rest – aim to have a rest day for every 600 to 900m you go up - and avoid smoking and drinking alcohol, or taking medications such as sleeping tablets.

How can I manage altitude sickness?

If you think you’re experiencing altitude sickness, you shouldn't continue climbing but instead, stop and rest where you are. Stay at that level for 24 to 48 hours until your symptoms have gone. It is very important to rest properly and not exercise or over-exert yourself whilst you are unwell. Again, you should drink plenty of fluids to avoid dehydration and avoid smoking or drinking alcohol.

There are medications available that can help manage your symptoms. Headaches can be helped with painkillers such as ibuprofen or paracetamol. Sickness can be helped with anti-sickness medications. Both of these are available from your local pharmacy.

A travel clinic or a private GP may prescribe acetazolamide tablets (they’re not available on the NHS for altitude sickness when travelling abroad) which may help prevent and manage altitude sickness. If after 24 hours you don't feel any better, then it’s important that you start to go down by at least 500m a time and reassess your symptoms. If your symptoms are worsening it’s very important you seek urgent medical attention.

What are the complications of altitude sickness?

Altitude sickness can lead to life-threatening and sometimes fatal conditions that can affect the brain or lungs.

High altitude cerebral oedema (HACE) occurs when a lack of oxygen causes the brain to swell. Unfortunately, people often don't realise they’re very unwell, and symptoms can develop very quickly including headache, nausea, weakness and confusion.

High altitude pulmonary oedema (HAPE) happens when fluid builds up in the lungs. This takes a few days and can be fatal, with symptoms including difficulty breathing, chest pain, persistent productive cough and tiredness.

Prescribed medications such as dexamethasone or nifedipine are available that can help with the symptoms of either of these serious problems and should be taken sooner rather than later. It is always important to seek medical attention as soon as possible.

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Dr Roger Henderson
Reviewed by Roger Henderson
Reviewed on 29.04.2024
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