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 arriving in Lhasa.

Symptoms tend to be worse at night and when respiratory drive is decreased. Mild AMS does not interfere with normal activity and symptoms generally subside within two to four days as the body acclimatizes. As long as symptoms are mild, and only a nuisance, ascent can continue at a moderate rate.

The altitudes of different places in Tibet

Do not overexert yourself or more higher for the first 24 hours.

Drink extra fluids. The mountain air is dry and cold and moisture is lost as you breathe. Evaporation of sweat may occur unnoticed and result in dehydration.

Take it easy and don't overexert yourself when you first get up to altitude. But, light activity during the day is better than sleeping because respiration decreases during sleep.

Avoid alcohol as it may increase the risk of dehydration, and don't smoke.

Don't push yourself when climbing up to passes, rather take plenty of breaks.

If you begin to show symptoms of moderate altitude sickness, don't go higher until symptoms decrease.

Avoid catching cold before you entering Tibet.

Prepare some AMS pills according to your doctor's suggestion.

Everyone should have more or less altitude symptoms. However, those who have the following symptoms may not going to Tibet

1. something relating to Tuberculosis, pneumonia, serious tracheitis, bronchitis

2. Serious heart attack, high blood pressure

3. have already got a serious cold