Acute Mountain Sickness(AMS) is common at high altitudes, and depends on the elevation, the rate of ascent and individual susceptibility. Most visitors to Tibet will suffer from at least some symptoms that will generally disappear through acclimatization in several hours to several days.

Symptoms tend to be worse at night and include headache, dizziness, lethargy, loss of appetite, nausea, breathlessness and irritability. Difficulty sleeping is another common symptom, and many travelers have trouble sleeping for the first few days after arrival at Lhasa.

An altitude over 3,000 meters (9,843 feet) is usually defined as high altitude. Since most places in Tibet are higher than this level. Acute Mountain Sickness (AMS), also called Altitude Sickness is the biggest health risk to tourists travelling in Tibet. AMS is common at high altitudes due to the decreasing availability of oxygen. Most people will suffer differing degrees of symptoms at high elevation. The occurrence of AMS is dependent on the altitude, the ascent rate and individual physical condition. Symptoms of AMS include headache, nausea, dizziness, fatigue, shortness of breath, loss of appetite and disturbed sleep. Most people will experience one or more AMS symptoms upon their arrival in Tibet. The symptoms will usually gradually decrease in severity during acclimatization. Mild AMS usually will not interfere with mild activity.

However AMS can be very serious, with the most serious symptoms being High Altitude Pulmonary Edema (HAPE) and High Altitude Cerebral Edema (HACE), which can be fatal. Symptoms of HAPE include weakness, shortness of breath, even at rest, impending suffocation at night, and a persistent productive cough with white, watery, or frothy fluid. Symptoms of HPCE may include headache, ataxia, weakness, hallucinations, psychotic behavior, coma and loss of memory. Both approach and strike at night and can be fatal! Immediate descent is the surest treatment.

AMS can be lessened or avoided with proper acclimatization, which will also ease and reduce AMS symptoms. A gradual ascent will allow your body to acclimatize to higher altitudes and the decreased oxygen supply. Go no higher 300 - 400 hundred meters (984 - 1,312 feet) daily and have a rest after each 1,000 meter (3280 feet) ascent. Medication also helps to prevent AMS. Mild AMS symptoms can be treated with proper medication. If medication does not relieve the symptoms, go to hospital or evacuate immediately to safe altitude!

The following precautions may help to prevent or lessen the effects of AMS:
Before you go to Tibet
* Seek advice from people who have similar experiences. The most important thing is that you should never be nervous or worried about your trip. Regard the trip to Tibet like a trip to any other cities. You should always be optimistic.

* If you have respiratory problems, we advise you to postpone your trip till you are fully recovered.

* A thorough physical examination is necessary. If you have problems like anemia or hypertension, or suffer from heart problems and other illness of lungs, liver or kidney, you should not go to Tibet.

* You need to bring enough water or drinks and fruits. Snacks with high caloric content, like chocolate, will come in handy.

When you are in Tibet
* Rest right after your arrival. You should not do anything strenuous on the first day. Brisk walking and running are not advised. We suggest that you neither smoke nor drink alcohol. Do not eat too much for dinner.

* It happens quite often that people feel short of breath. If it is not serious, please do not rely on oxygen equipment all the time so that you can acclimatize yourself to the high altitude as early as possible.

* Do not take showers or bathes too frequently especially on your first night in Tibet. This will help you avoid catching severe colds.

* If you feel chilly or feel very uncomfortable, you need to tell your guide about this. Your guide could send you to the best hospital available in the area.

Preventive Medication
Diamox (Acetazolamide) have been found helpful. It allows you to breathe faster so that you metabolize more oxygen, thereby minimizing the symptoms caused by poor oxygen supply. Since it takes a while for Diamox to have an effect, it is advisable to start taking it 24 hours before you go to altitude and continue for at least five days at higher altitude. The recommendation of the Himalayan Rescue Association Medical Clinic is 125 mg, twice a day (morning and night) but you are recommended to consult your physician for the prescription.

Hongjingtian
Tibetan herbs are still good preventive and treatment effects for AMS. Honjingtian (Rhodiola Eoccinea) may help sleep at high altitude and thus increase oxygenation at night.

Who can't go to Tibet?
Suggest who suffered from high blood pressure and severe heart disease not travel to Tibet.