High Altitudes

Trekking to high altitude (generally this means above 2500 metres) involves additional risk not normally associated with lower level treks. This is not something that should prevent you from undertaking a trek in the Himalaya or Andes or any of the world's greater ranges. However, before embarking on such a holiday, it makes sense to learn about the dangers inherent in trekking at high altitude and also the ‘golden rules' to prevent Acute Mountain Sickness (AMS).

Trip selection

For each of our holidays the maximum altitudes attained are listed on the web site and in the heading of the individual Trip Notes. In addition, the altitudes of each camp and each pass are listed in the daily itinerary of the trip dossier. You should read the Trip Notes carefully and use your own judgement to gauge whether your chosen holiday is suitable for your level of experience. If you have any doubts at all you should contact the KE office. Our experienced staff are more than happy to talk about altitude related issues on our holidays.


The human body is capable of adapting to a very wide range of barometric pressures. This adaptation process is known as acclimatisation and it does take time. The most important rule is to gain height slowly and it is generally accepted that the maximum safe altitude gain in any one day is 500 metres once above 2500 metres. Where this is not possible (for example because you are trekking in Bolivia where you have to fly in to La Paz International Airport at 4100 metres, or where there is no place to camp within 500 metres of your last camp), then it is important to have a rest or acclimatisation day at the new altitude before gaining further height. All our itineraries follow this rule. In general the maxim ‘climb high and sleep low' applies. It is perfectly acceptable (and even beneficial to your acclimatisation) to climb higher than 500 metres above your last camp (for example when crossing a high pass) as long as the increase in sleeping altitude remains within the above rule.


There is a correlation between daily fluid intake and successful acclimatisation and you must pay particular attention to hydration during trekking at high altitudes. On treks to 3000 metres and above most people will need to drink between 5 and 6 litres each day to achieve suitable hydration levels and you must adopt a responsible approach to achieving this target.

Acute Mountain Sickness

Before embarking on a trek to high altitude it is important that you familiarise yourself with the signs and symptoms of Acute Mountain Sickness (AMS) and that you report any illness to your tip leader straight away. See the links at the bottom of this page for further reading on AMS.


There are a number of untested herbal remedies which claim to prevent mountain sickness. However, only one drug is currently known to have a useful role in preventing AMS and to be safe for this purpose: acetazolamide (Diamox). We recommend that you carry Diamox in your first aid kit for high altitude treks. Diamox can only be obtained from a medical professional on prescription and it is important that you first consult your own doctor so that you know there are no contra indications with other medicines you may be taking and that you do not have an allergy to acetazolamide. Diamox commonly causes some minor side effects, such as tingling fingers and toes, or a metallic taste in the mouth, but more severe reactions are rare. On trek, the decision whether or not and when, you should take Diamox as with any drug, will rest solely with you. If you intend to take Diamox, you must familiarise yourself with the appropriate dosage and regime prior to coming on the trip. The links at the bottom of this page will provide further information on the use of Diamox as an aid to acclimatisation.

Emergency equipment

For our trips to extreme altitude (those which trek above 5000 metres or where you sleep above 4000 metres), we carry a portable altitude chamber (PAC) and/or bottled oxygen. A PAC is a sealed bag, big enough for a person to comfortably fit inside, which can inflated with a constant air flow and is used to simulate rapid descent.  A person suffering from AMS can be effectively 'brought down' as much as an equivalent of 2000 metres in a matter of minutes inside a PAC bag. All KE High altitude trek leaders are trained in the use of PAC bags. We also carry a PAC and/or bottled oxygen on any trek above 3500 metres where fast descent is not immediately possible.

Travelling to high altitudes is not something you need to be scared of. Every year thousands of people enjoy the most amazing experiences in the world's greatest mountain ranges. Altitude sickness is entirely preventable if you follow very simple rules and procedures. Please make sure you are aware of these before you travel.

More information

For further reading on the above issues we recommend the following websites: