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Altitude sickness is an issue faced by many adventurous trekkers and climbers and it’s not just those climbing mountains like Island Peak (6,189m), or trekking to Everest Base Camp (5365m) as you might expect. Altitude sickness, also known as Acute Mountain Sickness (AMS), can be encountered by anyone reaching heights of 2,500m and above, so it’s even possible for skiers in the Alps to experience it, particularly in higher resorts such as Zermatt (Switzerland) and Val Thorens (France).

It is therefore important that all travellers are aware of altitude sickness and the potential consequences of not recognising and treating symptoms before they develop into anything more serious. While most cases are mild and perfectly manageable, some cases (especially those above 3,500m) can develop into potentially life threatening conditions, so it is vital to recognise the symptoms and treat them promptly.

Symptoms & Prevention


Symptoms of mild altitude sickness are: 

  • Headaches

  • Shortness of breath

  • Decreased energy levels

  • Dizziness

  • Nausea and vomiting

  • Diarrhoea

  • Loss of appetite

  • Trouble sleeping

Symptoms of severe altitude sickness are:

  • Worsening of mild symptoms

  • Confusion and irrational behaviour

  • Uncontrollable coughing

  • Blurred vision

  • Hallucinations

  • Coughing up fluid

  • Convulsions

Without attending specialist altitude centres for extensive testing and training, there is no way to predict who might develop altitude sickness. Strangely, a seasoned climber is just as likely to develop it as someone who has never been at altitude before, and someone who has once been at altitude and not experienced any problems, may the next time find themselves with more severe symptoms.

There is no correlation between the level of fitness and the chance of developing altitude sickness – even the fittest and healthiest of individuals may suffer. And don't be fooled into a false sense of security – just because you have not developed altitude sickness before, doesn’t mean you won’t in the future.


There are a number of things you can do to reduce your chances of developing altitude sickness on a trek:

  • Ascending slowly and taking time to acclimatise is vital. It is recommended to ascend no more than 400m-800m a day, particularly when above 3,000m

  • Keep yourself well hydrated with water and avoid alcohol as much as you can - a minimum of 3 Litres a day is recommended

  • Make sure you keep your energy levels up by eating a high calorie diet

  • Medication - see below


There are numerous medications available, including both pharmaceutical drugs and herbal remedies, that are aimed at preventing altitude sickness or reducing symptoms. Only one of these medications, acetazolamide (commonly known as Diamox), has been proven to be safest and most effective. This is prescription-only medication so you’ll need to visit a travel clinic prior to your trip to obtain it, however our guides also carry some for you to use should you need it. Not everyone uses medication as treatment, many prefer to follow the rules of slow ascent, hydration and even descending to recover before continuing.

Altitude sickness causes chemical changes in the blood and acetazolamide works by balancing these chemical changes, which in turn reduces symptoms. Unfortunately, as with every medication, acetazolamide has side effects. One of the most common side effects is the increased need to urinate, which can be frustrating while trekking.

It is also common to experience tingling sensations in the hands and feet. Tingling sensations can also be a sign of frostbite, so keep your hands and feet wrapped up warmer if trekking in colder climates and check them regularly if you are experiencing this.



Mild altitude sickness can be managed by treating the symptoms. Basic painkillers such as paracetamol or ibuprofen can help alleviate headaches, while promethazine can help reduce nausea and vomiting. Acetazolamide/Diamox can also be used to treat altitude sickness if it is not already being taken as a preventative method. Consult your pharmacy to discuss doses for both prevention and treatment.

If you have developed mild altitude sickness you should not progress to a higher altitude until your symptoms have been adequately managed. If you find your symptoms are getting progressively worse and not improving with treatment, descend immediately and seek medical attention before the condition becomes more serious.

In some cases symptoms can develop into one of two potentially life-threatening conditions: High Altitude Pulmonary Oedema (HAPE) or High Altitude Cerebral Oedema (HACE) – or they can develop together. HAPE is when the lack of oxygen at high altitude causes a build-up of fluid in the lungs; HACE is the lack of oxygen causing a build-up of fluid in the brain. Both can lead to a loss of consciousness and death within hours.

The symptoms of HAPE are breathlessness even when you are resting, a high temperature and coughing up frothy spit. Symptoms of HACE are confusion and stumbling and uncharacteristic behaviour such as laziness, excessive emotion or violence. Oxygen can buy time and acetazolamide should be given if available but immediate descent is essential.

It is important you are honest with your guides as they are experienced and trained to advise you on treatments and any required care. Your safety is the most important thing - if you have any symptoms, communicate them to your team and guides. Don't worry about feeling like you're 'moaning' if you have a headache, if it's a symptom of altitude sickness your guides will be able to advise you of treatment and will continue to monitor your symptoms to ensure you remain safe and healthy. Some people may worry that voicing a symptom would mean the end of the trek - this is not the case. Following the advice of our expert guides, drinking more water or perhaps joining Team Diamox - will have you feeling better and the majority of the time you'll be able to continue on with the trek. In rare circumstances symptoms do unfortunately worsen which means it's time to get you down from the mountain to lower ground where you can recover - this is why it is crucial that you include helicopter evacuation when you obtain your insurance.

To finish...


So to summarise, the advice is simple: ascend slowly, re-hydrate and treat symptoms as soon as they occur. If you feel you're getting worse it's time to descend until you feel ready to continue or use preventative medication. Altitude sickness may seem daunting, but don't let it put you off of a trek of a lifetime! Our guides are all trained, with years of experience, and will make sure you not only have a fantastic experience, but that you're safe and looked after whilst you're at it.

Overall have a great time wherever you are at altitude, but be aware of the signs and symptoms and mentally assess where your body is at that point.

Happy trekking!


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