Acute Mountain Sickness(AMS)


As all our Annapurna/Everest Treks go above 2,000 meters, Nepal Trek Ways schedules are carefully designed to minimize the effects of Altitude. We ascend slowly, for safe acclimatization. Headaches and breathlessness (The first symptoms of Mountain Sickness) are common at altitude and are, in themselves, nothing to worry about. In rare cases, this may develop into Acute Mountain Sickness(AMS),so the Guide keeps a close watch on everybody, as he/she is trained to recognize the symptoms .If anyone shows signs of severe headaches, nausea, lethargy or in extreme cases, ataxia (loss of co-ordination) and serious breathlessness at rest, they will be evacuated to a lower altitude immediately. The Guide’s decision to descent is final. The worst effect of altitude is worrying about Altitude! As long as you maintain your body fluids with at least 3-4 liters per day, ascend according to the itinerary, and are adequately fit, you will most likely to have no problems apart from the normal breathlessness on hills. Please inform your guide if you have any symptoms and/or if you are taking medication. Your Group Leader/guide can give you more advice, or you can consult the Himalayan Rescue Association in Kathmandu or any trekking book on our Reading List.

Acute Mountain Sickness (AMS)

Many people are concerned about altitude sickness. This problem, often known as acute mountain sickness (AMS), is a particularly important medical consideration while trekking in Nepal and Tibet. AMS rarely occurs lower than 2800 meters (9520ft) and only minor symptoms occur below 3000 meters (9,800ft). AMS occurs when the body does not adapt well to the lack of oxygen present at higher altitudes. At 5490 meters (18,000ft), there is just half the oxygen available as there is at sea level, while there is only a third available at the summit of Mount Everest. The itineraries of the treks of Nepal Trek Ways are designed to reduce the risk of altitude sickness as much as possible, although individual susceptibility to altitude sickness seems to be genetically determined.

Related Oxygen Rate at Different Altitude:

In Meters  In Feet

8.850         29.035    33%

8.000         26.247    36%

7.000         22.966    41%

6.000         19.865    47%

5.500         18.045    50%

5.200         17.061    52%

5.000         16.404    53%

4.500         14.764    57%

4.000         13.123    60%

3.500         11.483    64%

3.000         9.843     68%

2.500        8.202      73%

1.000        3.281      88%

Sea Level 100%

What happens to the body during altitude illness?

* The body tries to adapt to having less available oxygen by increasing the rate and depth of breathing, as well as the heart rate.

* Fluids accumulate in between the cells in the brain, the lungs or both, creating mild to severe symptoms.

* Mild symptoms include headache, loss of appetite, nausea, fatigue, insomnia and dizziness. These symptoms are usually resolved by spending one or two extra nights at the same altitude. If symptoms worsen, descent to lower altitudes is warranted.

* If you are resting at the same altitude and your symptoms worsen, then it is also necessary to descend.

* More serious symptoms of AMS include increased tiredness, severe headaches, vomiting, loss of coordination, shortness of breath and coughing fits.

* These extremely dangerous symptoms are called high altitude cerebral edema (or HACE). They can lead to unconsciousness and death within 12 hours.

* Increasing shortness of breath, cough and tiredness may also be signs of high altitude pulmonary edema or HAPE. This condition can rapidly prove to be fatal if ignored.

* Respiratory depression (the slowing down of breathing) can be caused by various substances, and may be a problem at altitude.

The following substances can do this, and should never be used by someone who has symptoms of altitude illness:

* Alcohol

* Sleeping pills (acetazolamide is the sleeping tablet of choice at altitude)

* Narcotic pain medications in more than modest doses

To prevent AMS and respiratory depression, drink at least three liters of liquid a day and avoid getting cold.

Altitude sickness can to a certain extent be prevented by acetazolamide (Diamox SR), 750mg per day. Some experts suggest a two-day trial of acetazolamide before the trip. Please seek the advice of your personal physician. Please note that taking Diamox SR does not mean that you can ignore advice about proper acclimatization.

To recap, serious symptoms of altitude sickness include:

* A severe, enduring headache, which is not cured by ordinary painkillers

* Nausea and repeated vomiting

* Irritating dizziness or actual difficulty with balance and direction

* Visual disturbances with flickering vision and problems judging distance

* Pressure in the chest, rapid breathing and pulse rate, crackles in breathing and shortness of breath

* Swelling beneath the skin (edema), typically around the eyes

* Swollen ankles and hands

* Confusion

* Convulsions

In the presence of these symptoms, medical attention must be sought immediately in conjunction with descent to the lowest possible height.

We have guides trained at the High Altitude Medical Training Center. Our staff is very experienced in dealing with the effects of higher altitudes. As they are natives of Nepal, they easily acclimatize and therefore can care for their clients.

They are equipped with necessary medical supplies and will assist with basic first aid treatment. We design our tours to ensure clients are ready for high altitude, and arrange alternative itineraries for those at risk.

For more information, please contact your doctor or hospital or contact us arrange High Altitude expert Doctors or visit their clinic in Kathmandu.

How can I prevent Mountain Sickness?

The complications of Mountain Sickness are preventable if people listen to their bodies and follow simple guidelines: • Pay attention to your body and be aware of the initial AMS symptoms of AMS. Do not ascend with these symptoms. • Ascend slowly. Increase your sleeping altitude by only 1000-1500 feet per day. Try climbing higher during the day and coming down to sleep. (Climb high, sleep low) • Descend if the symptoms become severe or if you begin to experience HACE and/or HAPE. • Drink 2 liters (2 regular size Nalgene bottles) of water per day, in addition to the usual tea and other beverages. • Dress properly for high altitude treks, with synthetic under shirts for removing sweat, a warm fleece jacket, and a down jacket to prevent hypothermia, which can predispose you to AMS and its complications.

Nepal Trek Ways encourages all trekkers to procure emergency evacuation insurance prior to their trip to Nepal.

What is Altitude?

Altitude is height above mean sea level. If the sea level in a certain place is 100 feet and you are 250 feet above the ground, your altitude above sea level would be 350 feet, and your altitude above ground level would be 250 feet. We all enjoy the tremendous view from a high summit, but there are risks in going to high altitude, and it’s important to understand these risks. Given time, your body can adapt to the decrease in oxygen molecules at a specific altitude. This process is known as acclimatization and generally takes 1-3 days at that altitude.

How long does acclimatization last?

It varies, but if you were at altitude for a month or more your improved work rates can persist for weeks meaning you still feel fit upon returning to altitude. You still should not ascend faster than normal if you return to sea level for a few days, otherwise you are susceptible to HAPE.

If you have been to 5000m/16,404ft then go down to 3500m / 11,483ft for a few days, returning rapidly to 5000m/16,404ft should cause no problems, i.e. having been to Lobuche and Kala Pattar, and then rested for two days in Namche you should be able to ascend to Gokyo quickly without problems

Sleeping at altitude

Many people have trouble sleeping in a new environment, especially if it changes every day. Altitude adds to the problems. The decrease of oxygen means that some people experience wild dreams with this often happening at around 3000m. Compound this with a few people suffering from headaches or nausea, a couple of toilet visits, a few snorers and periodic breathers, and it takes someone who sleeps like the proverbial log (or very tired trekker) to ignore all the goings on at night in a large dormitory. Smaller rooms are a definite improvement, and tents, although not soundproof are still manage to be relatively peaceful.

Altitude Sickness Information

Individual rates of acclimatization vary enormously but ascending very rapidly and staying there will always result in problems. Altitude sickness often known as Acute Mountain Sickness (A.M.S.) in general may occur when people ascend too quickly normally in altitudes of over 3000 meter. We ensure minimal risk by building in rest days into our trekking itineraries. Most people will feel some affect of altitude, shortness of breath and possibly light headed, which is fairly common. Acute mountain sickness is very different and normally involves a severe headache, sickness and loss of awareness. In almost every potential case there are enough warning signs to take appropriate action.

Our experienced and well trained guides will advise you about any health issues and also altitude sickness while you are on trekking, so you should not worry about it. Before leaving for the trip we suggest to consult with your Medical Doctor and get advice. The following information gives you an idea about high altitude sickness and how to minimize the effects.


Thousands of Trekkers come to the Himalaya annually, many on very limited budgets, so the horror stories of bad treks, stomach problems and A.M.S. are mostly true. In the past, tea-house trekking could be hazardous, only undertaken by the brave or the foolhardy! However the facilities are now greatly improved and to a large degree, standardized. It need not be a uncomfortable alternative anymore, if you follow the guidelines we have given you about personal hygiene, rubbish disposal and environmental protection. It’s the little things that make the difference; before you clean your teeth on the trek, think about where the water has come from! It will not be 5star, but, you would not have come to Nepal to trek if you were expecting that! But you have chosen, very sensibly, to travel with a company with many years service experience of taking the fears out of trekking. We can’t control the weather, but we do work constantly to give you the holiday of a lifetime, by controlling the food you eat and your rate of ascent and monitoring your safety and well-being at all times.

A little bit of common sense, patience and tolerance goes a long way. So, while we are always ready to assist you in having the holiday of your life-time, the old adage about ‘Getting back what you put in’ is especially true here. A trekking holiday doesn’t appeal to everyone and

honestly, half way up the first hill you may wonder why you’re not on a beach somewhere. However, at the first sight of the mighty Mountains and the environment you will know why you chose Nepal and why trekking is the ultimate holiday. It is a time to reflect, take photographs make new friends among vastly different people, to sit in the sun and gaze up at soaring peaks of ice and rock, to relax and have fun in the company of great people.

Nepal is a developing country and sometimes things happen on time but mostly they don’t. Nepal Trek Ways appreciates that this is your Holiday and that you want things to happen when they are supposed to, but we can’t control the weather! While we will do our best to rectify the situation, please understand that delays are commonplace in this part of the World. We are sure you will appreciate this and accept this and it as part of the whole Nepal experience. Leave your watch at home and take things as they come. You will quickly become accustomed to the relaxed pace and are likely to reassess your usual frantic schedule! Enjoy your trek.