纳木错，藏语意为"天湖"，是西藏三大圣湖之一。湖面海拔4718米，东西长70公里，南北宽30公里，面积1920平方公里，是西藏自治区最大的湖泊，是我国第二大咸水湖，也是世界上海拔最高的大湖。纳木错是新生代第三纪因喜马拉雅运动陷而成。第三纪末和第四纪初湖面面积很大，全新世以后因西藏气候变干，湖泊面积大为缩减。现存古湖岸线三道，最高一道距现在湖面80米。湖滨地形开阔，分布在广泛的湖滨平原、沼泽地和沙滩。纳木错是深水湖，湖水清澈，透明度大，矿化度低，湖面呈深蓝色。湖水冬季结冰，翌年5月开始解冻。湖中盛产细鳞鱼和无鳞鱼。湖滨平原水草茂盛，有野驴、黄羊、狗熊、狐狸、野兔等野生动物活动。
纳木错是著名的朝圣地。伸入湖心的扎西半岛上有扎西寺（扎西、藏语吉祥的意思），至今仍香烟缭绕，暮鼓晨钟。每当藏历羊年，有数以千计的信徒不畏长途跋涉来到这里朝圣。从拉萨乘车沿青藏公路向北抵当雄向西，当天即可到达纳木错。
This text does not mean to scare you away, but rather to warn you of dangers that you can face with little problems if you take some simple precautions.
Generally altitude over 3,000 meters (9,843 feet) is defined as high altitude. Since most places in Tibet are higher than that level, Acute Mountain Sickness (AMS), also called Altitude Sickness is the biggest health threat to tourists in Tibet. AMS is common at high altitudes due to the decreasing availability of oxygen. It is usual that most people will experience symptoms at different levels at that 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. Many people will experience one or more AMS symptoms upon their arrival in Tibet. The symptoms will usually decrease in severity gradually during the acclimatization. Mild AMS is usual and will not interfere with mild activity.
However AMS can be very serious. The most serious symptoms are 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.
Before visit to Tibet, get as fit and healthy as possible, both physically and psychologically. Visitors having record of heart, lungs and other organ problems or anemia should consult their doctor before making the decision to visit Tibet.
AMS can be lessened or avoided. Proper acclimatization can also ease and reduce AMS symptoms. A gradual ascent will allow your body to acclimatize to higher altitudes and the decreased oxygen supply. Go higher 300 - 400 hundred meters (984 - 1,312 feet) daily and have a rest after every 1,000 meter (3280 feet) ascent. Medication also helps to prevent AMS. Mild AMS symptoms can be cured with proper medication. Once medications do not respond to the symptoms, go to hospital or evacuate immediately to safe altitude!
The following precautions may help to keep AMS away from you:
Since fluid loss usually accompanies the acclimatization process, drink plenty of fluids (3 - 4 liters daily at least) and eat carbohydrate food to maintain properly hydrated;
Do not over exert and maintain light activity right after your arrival;
Stay way from smoking and alcohol and other depressants such as tranquilizers and sleeping pills, which will depress the respiratory drive and oxygen intake.
Always keep in mind the following rules which may ensure you a smooth and enjoyable trip to Tibet:
Any sickness at high altitude is AMS until proven otherwise; Never go higher with symptoms of AMS;
It is significant that you report any symptoms of AMS immediately to other group members in the trip.
What is Acute Mountain Sickness (AMS) And How to Avoid ItThe high altitude and people's reaction to it is one of the difficulties to travel to Tibet. But it is not so serious as you imagined if you know it and get prepared for it.
What is High Altitude?- High Altitude: 1500 - 3500 m (5000 - 11500 ft) - Very High Altitude: 3500 - 5500 m (11500 - 18000 ft) - Extreme Altitude: above 5500 m
When acclimatization lags significantly behind ascent, various symptoms occur. Acute Mountain Sickness (AMS) represents the body's intolerance of the hypoxic (low oxygen) environment at one's current elevation
What kinds of physiologic reactions will occur?- Hyperventilation (breathing fast) - Shortness of breath during exertion - Increased urination - Changed breathing pattern at night - Awakening frequently at night - Weird dreams
The altitudes of different places in Tibet
Tips to avoid AMS- Do exercises to keep you fit before coming to Tibet.- Avoid catching a cold.- Make sure you have a good sleep the night before you flying to Lhasa.- You'd better not to take any activities for the first day in Tibet.- After getting off your airplane in the airport, walk slowly, take some deep breath. Do not do anything severely.- Ascend to higher altitude gradually. DO NOT ASCEND ANY HIGHER if you feel bad.- Prepare some AMS pills according to your doctor's suggestion.
High Altitude Sickness
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.
To prevent acute mountain sickness:
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.
Eat light, high-carbohydrate meals for more energy.
Avoid alcohol as it may increase the risk of dehydration, and don't smoke.
Avoid sedatives.
Don't push yourself when climbing up to passes, rather take plenty of breaks.
Avoid catching cold before you entering Tibet.
Tibet Tour Expert says:
For all of the groups , the authorized doctor from Tibet Tour Expert will come to guest's room to give a regular check. For the people who are affected severely with headache and sleepless, they could get injection in the room or take some Tibetan medicine as per doctor's advices. Many of our clients have been treated and approved for its efficiency.
Who can't go?
Tibet Tour Expert may suggest whose clients who suffered from high blood pressure and severe heart disease not travel to Tibet.
