Altitude sickness is also known as acute mountain sickness. Altitude sickness can happen to anyone, no matter your fitness level, age or experience. 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 2500m above sea level, often when mountain climbing but also in cities that stand high above sea level.
Symptoms usually develop within a day of reaching the altitude level. You may feel a gradual headache come on, you may also feel sick, dizzy, tired and disoriented. You may find it difficult to breathe and feel short of breath. Remember that if you feel unwell, it is altitude sickness until proven otherwise.
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 do not fly directly to these levels but climb them 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, and avoid smoking and drinking alcohol, or taking medications such as sleeping tablets.
If you think you are 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 may prescribe acetazolamide tablets, which may help prevent and manage altitude sickness. If after 24 to 48 hours you still don't feel yourself, then it is important that you start to go down by at least 500m a time and reassess. If your symptoms are worsening it is important you seek urgent medical attention.
Altitude sickness can lead to life-threatening conditions that can affect the brain or lungs. High altitude cerebral oedema occurs when a lack of oxygen causes the brain to swell. People often don't realise they are very unwell, and symptoms can develop very quickly. It includes symptoms like headache, nausea, weakness and confusion. High altitude pulmonary oedema is when fluid builds up in the lungs. This takes a few days and can also lead to death. Symptoms include difficulty breathing, chest pain, persistent productive cough and tiredness. There are prescribed medications such as dexamethasone or nifedipine that can help with the symptoms of either of these – they should be taken sooner rather than later. It is always important to seek medical attention as soon as possible.