High Altitude Precautions

Arrival: Changing time zones knock people, add the stress of winding up at work and many people arrive feeling slammed, needing a holiday. This is the time you are most likely to get sick; try to take it easy, and definitely take multi-vitamin tablets. If traveling from America the flights are particularly long with annoying stopovers and a brutal time change; we recommend arriving a day earlier to recover. For India if the trek begins in Leh then fly up there one day earlier..

High Altitude Medical Advice For Travelers: It's okay to get altitude illness, but it's not okay to die from altitude illness. Trekking in the Himalayas brings people to high altitude for longer periods of time than in most other situations, and the risk of dying from altitude sickness is consequently higher in this region. Trekking in Himalayas affords the opportunity to acclimatize gradually.

Human bodies have built-in adjustment mechanisms that can optimize performance at altitudes. This process is known as acclimatization. The power of acclimatization can be demonstrated by the following examples. If a person were transported suddenly to the summit of Mt. Everest (29,128 feet; 8848 mt.), person would lose consciousness in a few minutes, and most likely die within an hour or two due to acute hypoxia. However, over 60 people have climbed to the summit of Mt. Everest without using supplemental oxygen after acclimatization for many weeks. This fact demonstrates how profound the process of acclimatization can be.

AMS - Acute Mountain Sickness
Commonly called altitude sickness, this has the potential to affect all trekkers from 2500m and higher. Your body needs days to adjust to smaller quantities of oxygen in the air - at 5500m/18,044ft the air pressure is approximately half that of sea level, ie there is half the amount of oxygen (and nitrogen).

For treks below an altitude of about 3000m/10,000ft it is not normally a problem. AMS is caused by going up high too fast and can be fatal if all the warning signals are ignored. Note that it is not the actual altitude, but the speed at which you reach higher altitudes which causes the problems.

Altitude sickness is preventable. Go up slowly, giving your body enough time to adjust. These are the 'safe' rates for the majority of trekkers: spend 2-3 nights between 2000m/6562ft and 3000m/10,000ft before going higher. From 3000m sleep an average of 300m/1000ft higher each night with a rest day every 900-1000m/3000ft. Ultimately it is up to you to recognise the symptoms, and only ascend if you are relatively symptom-free.

Normal symptoms at altitude
Don't expect to feel perfect at altitudes of more than 3000m. These are the normal altitude symptoms that you should expect BUT NOT worry about. Every trekker will experience some or all of these, no matter how slowly they ascend.

  • Periods of sleeplessness

  • The need for more sleep than normal, often 10 hours or more.

  • Occasional loss of appetite

  • Vivid, wild dreams at around 2500-3800m in altitude

  • Unexpected momentary shortness of breath, day and night

  • Periodic breathing that wakes you occasionally - consider taking Diamox.

  • The need to rest/catch your breath frequently while trekking, especially above 4000m

  • Your nose turning into a full-time snot factory

Mild Symptoms

You only need to get one of the symptoms to be getting altitude sickness, not all of them.

  • Headache - common among trekkers. Often a headache comes on during the evening and nearly always worsens during the night. Raising your head and shoulders while trying to sleep sometimes offers partial relief. If it is bad you may want to try taking a painkiller: aspirin (dispirin), Paracetamol, Ibuprofen (Aduil) or acetamenophen (tylenol). Never take sleeping tablets. You could also take Diamox: see below. Headaches arise from many causes, for example, dehydration, but if you develop a headache assume it is from the altitude.

  • Nausea (feeling sick) - can occur without other symptoms, but often nausea will develop with a bad headache. If you are better in the morning take a rest day, or if you still feel bad descend.

  • Dizziness (mild) - if this occurs while walking, stop out of the sun and have a rest and drink. Stay at the closest teahouse.

  • Lack of appetite or generally feeling bad - common at altitude due to too rapid an ascent.

  • Painful cough or a dry raspy cough.

In other words anything other than diarrhea or a sore throat could be altitude sickness. Assume it is, because if you have a headache from dehydration, ascending further is not dangerous, but if its due to AMS, the consequences could be very serious. You cannot tell the difference, so caution is the safest course.

Do not try to deceive yourself and accept that you body needs more time to adapt.

Serious Symptoms:

  • Persistent, severe headache.

  • Persistent vomiting

  • Ataxia - loss of co-ordination, cannot walk in a straight line, looks drunk

  • Losing consciousness - cannot stay awake or understand things very well

  • Liquid sounds in the lungs

  • Very persistent cough

  • Real difficulty breathing

  • Rapid breathing or feeling breathless at rest

  • Coughing blood or pink goo or lots of clear fluid

  • Marked blueness of face and lips

  • High resting heart beat - over 120 beats per minute

  • Severe lethargy and drowsiness

  • Mild symptoms rapidly getting worse

Ataxia is the single most important sign for recognizing the progression from mild to severe. This is easily tested by trying to walking a straight line, heel to toe. Compare with somebody who has no symptoms. 24 hours after the onset of ataxia a coma is possible, followed by death, unless you descend.


Take as far down as possible, even if it is during the night. (In the Everest region: if you are above Pheriche, go down to the HRA post there. From Thorung Phedi or nearby: take to the Manang HRA post.) The patient must be supported by several people or carried by a porter - his/her condition may get worse before getting better. Later the patient must rest and see a doctor. People with severe symptoms may not be able to think for themselves and may say they feel OK. They are not.

Food Poisoning
This comes on suddenly and severely, usually from both ends - vomiting and diarrhea. It happens about 4 to 8 hours after eating the contaminated food. Luckily it usually lasts less than 24 hours and recovery is quick, although you may feel weakened. There are no drugs that can help - the body just has to eject all the contaminated food and rid itself of the poison. Rest and, once the first severe bout or two is over, drink plenty of fluids. Oral dehydration solutions are helpful.

While trekking lower down in the valleys it is hot and you sweat a lot so it is important to replace the fluids you lose. At altitude the problem is worse, you are still sweating and the air is dry and thin meaning you must breathe a lot harder. With every breath you breath out water vapour. It is very important then to drink a lot. Dehydration make you feel tired and lethargic and can give you a headache. The symptoms are similar to AMS so the easiest way to avoid confusion is to always keep hydrated.

The basic rules are; drink as much and as often as you like, (that does not include alcohol!) even if it seems like a lot. This can include soups and lots of tea, but even with a lot of liquid food, you should drink a lot of water too. Many people find that with dinner they often drink more than a litre of water, catching up on what they should have drunk during the day. A great guideline is the expression: A happy mountaineer always pees clear!

The easiest way to check that you are not becoming dehydrated is to look at your urine; if it is very yellow or orange you should drink more, but if it is almost clear then you have been looking after yourself well. Using this as a guideline some trekkers find that, although they don't feel thirsty, their urine is definitely yellow. This means drink more, even if you have to consciously think about it.
Since you spend most of your time walking, blisters are really worth avoiding. First use boots that have been worn in if possible. Test your boots by carrying a pack up and down hills - along level ground there is far less stress on your feet.
Normally you can feel a blister developing - some rubbing, or a hot spot, or a localized pain. Stop and investigate, even if it occurs during the first 5 minutes, or just in sight of the top of the hill; immediate action is best. The trick is to detect the symptoms before the blister develops. Put tape on or investigate what may causing the problem.

Blister Treatment - If you develop a blister then there are several approaches. If it is not painful then perhaps surround it (not cover it) with some light padding, eg moleskin, and see how it feels. If it is painful and causing problems then pierce it - clean the skin and sterilize the needle; holding the needle slightly above a candle or match flame for a second or two is effective. Do not cut away the blister skin until after a few days when it is dried out and no more use for protecting the delicate skin underneath. You can put protective tape over the top with some cotton wool to protect the blister, and some people even put the tape straight over the blister, with no protection.

If you have had a previous history of blisters or think that you are likely to get them take preventative action first! Use moleskin, a strong waterproof zinc-oxide tape or similar, and tape up troublesome areas first. Tape before you take your first step and be religious about checking, and replacing, the tape.