Acclimatization in Tibet

Nestled amid the daunting Himalayas and the Kunlun mountain ranges, Tibet is known for offering some spellbinding views of nature. However, traversing through such high altitudes becomes a difficult task with the lack of oxygen and the trekker can suffer from conditions like dizziness, vomiting, or sleeplessness. While some visitors are able to deal easily and quickly with these altitudes others may find themselves feeling quite sick.

When the traveler moves up to a high altitude quickly, flying or driving directly from sea level, altitude sickness may be a common occurrence. The result in such cases is clear and  the climber’s condition quickly gets worse. So, before planning a tour to Tibet, it is necessary that you inform yourself well about altitude sickness and how you can best take care of your body.

Altitudes and Acute Mountain Sickness

Here are the scales of Altitude:

8,000 – 12,000 feet (High)   [2,438 – 3,658 meters]
12,000 – 18,000 feet (Very High)   [3,658 – 5,487 meters]
18,000 feet and above (Extremely High)   [5,500+ meters]

I find most of our visitors can go up to 8000 feet easily without experiencing any problems with altitude. With the decreased availability in oxygen, the rate of breathing becomes higher as the body is trying to breathe faster to take in more oxygen. However, at 8,000 feet oxygen levels in the blood remain the same as when doing household chores at sea level so we don’t have too much to worry about generally at such altitudes unless there is a severe pre-existing medical condition.

While every body adjusts to altitude differently, the symptoms of  Acute Mountain Sickness (AMS) generally start to show above the altitude of 10,000 feet. So it is best to try to take 2-3 days adjusting to the altitude around 10,000 feet before ascending higher.

AMS becomes severe as the elevation becomes higher. Try to avoid going to such high altitudes directly from sea level. The traveler’s condition can get worse when they sleep, since the body’s respiration decreases during sleep.
If you can acclimatize properly that is great but if not- move back down. There are preventive AMS medicines which can be taken but make sure you consul a doctor first as there might be side effects or allergic reactions to these.

You can also take test for Ataxia (a lack of coordination due to decreased brain function). Ask the potentially affected person to walk in a straight line, placing his toe to his heel and so on. If that person fails that simple test, start moving down immediately because this is a pretty good sign that AMS has advanced into a moderate or severe condition.

What Causes Altitude Illnesses

The concentration of oxygen at sea level is about 21% and the barometric pressure averages 760 mmHg. As altitude increases, the concentration remains the same but the number of oxygen molecules per breath is reduced. At 12,000 feet (3,658 meters) the barometric pressure is only 483 mmHg, so there are roughly 40% fewer oxygen molecules available per breath. In order to properly oxygenate the body, your breathing rate (even while at rest) has to increase. This extra ventilation increases the oxygen content in the blood, but not to normal sea level concentrations. Since the amount of oxygen required for activity is the same, the body must adjust to having less oxygen. In addition, for reasons not entirely understood, high altitude and lower air pressure causes fluid to leak from the capillaries which can cause fluid build-up in both the lungs and the brain. Continuing to higher altitudes without proper acclimatization can lead to potentially serious, even life-threatening illnesses.


The major cause of altitude illnesses is going too high too fast. 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. For example, if you hike to 10,000 feet (3,048 meters), and spend several days at that altitude, your body acclimatizes to 10,000 feet (3,048 meters). If you climb to 12,000 feet (3,658 meters), your body has to acclimatize once again. A number of changes take place in the body to allow it to operate with decreased oxygen.

  • The depth of respiration increases.
  • Pressure in pulmonary arteries is increased, “forcing” blood into portions of the lung which are normally not used during sea level breathing.
  • The body produces more red blood cells to carry oxygen
  • The body produces more of a particular enzyme that facilitates
  • The release of oxygen from hemoglobin to the body tissues.

10 Guidelines for Better Acclimatization

Following are some tips for better acclimatization:

1.) Slowly gain altitude

If you go above 10,000 feet (3,048 meters), only increase your altitude by 1,000 feet (305 meters) per day and for every 3,000 feet (915 meters) of elevation gained, take a rest day.

2.) Keep your body properly hydrated

Acclimatization is often accompanied by fluid loss, so you need to drink lots of fluids to remain properly hydrated (at least 3-4 quarts per day). Urine output should be copious and clear. Keep on drinking enough Oral Rehydration Salts,  water, and other beverages like juice, soup, and milk. In the place of plain water, drink garlic flavored water. You can keep pieces of garlic in your water bottle and this will help regulate the oxygen levels back to normal. Too much black tea and coffee is a no-no because these things dehydrate you.
Also avoid over hydration.
Do not force yourself or anyone else to drink water if they are not feeling thirsty. This might lead to vomiting or even worse.

3.) Avoid sleeping at high altitudes

The respiration rate in one’s body declines when a person sleeps. Thus, it is recommended spend a full day at high altitudes and then descend to lower altitudes in the evening hours. The mantra for mountaineers is “Climb high and sleep low”.  It is very important to make sure you are sleeping as low as possible even if you were up high in the day.

4.) Do not over exert yourself

It is advisable that you should avoid unnecessary exertion. Do not indulge in any excessive mental or physical activity as it may lead to heavy breathing and even headaches and nausea. Even simple tasks like walking slowly can be exhausting with the lack of available oxygen so limit your activity and make sure you are getting lots of rest.  If you happen to be hiking, walk at a slow, consistent pace.  I have seen lots of young guys try to impress their macho friends and end up throwing up because they pushed a little too hard and it caught up with them.

5.) Avoid alcohol and drugs

When traveling at altitude it is best to hold off on the consumption of alcohol, anti-depressant drugs, tobacco, and smoking.
Also avoid anti-depressant medications such as sleeping pills, tranquilizers, and barbiturates. Consumption of these substances can lead to respiratory problems during sleeping, thus worsening your condition at altitude.

Remember:  Save the celebration beer for your return journey after you have already ascended and descended and when you are back below 10,000 feet!

6.) Keep your body warm

Always keep your body warm by wearing layers with synthetic, down, or wool fibers. Make it a point that your clothes are always dry by changing your socks and undergarments daily (especially before bed). It is best to wear wicking fibers like polyester long underwear to keep the fabric next to your skin warm and dry.  When at high altitudes the best way to stay warm is to stay dry so the freezing temperature does not suck heat from your body with moisture.  Also make sure you pee before you go to bed as the excess water in your body requires unneeded heat and energy to keep it warm.

7.) Consume enough carbohydrates

When you are at high altitudes, it is best that you eat a diet that is high in carbohydrates. Our body absorbs 70% of its calories from carbohydrates. Also, consume simple foods that are not likely to upset your stomach.

8.) Avoid sleeping in the day time

It is best if you completely avoid sleeping in day time. If you do feel sleepy, you can indulge yourself in a little nap but if you do so, try to sleep in upright position. This helps keep the blood in your head (and prevents headaches) and aids in better respiration.
Lay your back against the wall or the back of the bed and try to sleep in that position. Another option is just in trying to keep your head at a higher level than the rest  of your body. Where possible try to use a pillow or a fleece to prop your head above your shoulders.

9.) Pack preventive medicine for AMS

As you plan a tour to Tibet, it is advisable that you should consult your doctor about  suitable AMS preventive medicines for yourself and those accompanying you. Also be sure to ask your doctor about any potential side effects or any other likely allergies.  Most high altitude medicine like Diamox increases your oxygen absorption in your blood and needs to be taken at least a few days before traveling to altitude.

10.) If possible, pack a small Oxygen cylinder

If it is possible, you can pack a small Oxygen cylinder to take care of the symptoms of AMS. Using oxygen will surely help but it is advisable that before using the kit, consult your doctor about the amount of oxygen that has to be inhaled during the trip (ie: the flow rate and the percent of oxygen used in the bottle).  In the case of an emergency, regularly and slowly breathing bottled oxygen can help a lot in alleviating high altitude sickness.

And, of course, the best remedy to altitude sickness is always to descend to a lower altitude as fast as possible.  Even a change of 100o feet in altitude can make a big difference in how you are feeling.


Symptoms of AMS (Acute Mountain Sickness) 
The following is a list of symptoms and possible cures for the different levels of AMS:

Mild AMS

Symptoms: Headache, faintness, tiredness, shortness of breath, loss of appetite, vomiting, troubled sleep, and a feeling of sickness

Possible cure: Medication and/or descend


Moderate AMS

Symptoms: Reduced coordination (ataxia), Severe headache (not relieved by medicine), other mild level symptoms with increased effect

Possible cure: Advanced Medication and/or Immediate Descent around 305-610 m


Severe AMS

Symptoms: Inability to walk, declining mental status, and fluid build-up in the lungs

Possible cure: Emergency Evacuation, Oxygen, Gamow Bag (a portable Hyperbaric chamber) Immediate Descent around 610-1,220 m


Preparing for High Altitude

Elevated Trips is a tour operator on the Tibetan Plateau.

At Elevated Trips our views are elevated but so are our knowledge and professional care in the mountains.

One thing that defines our business  as “Elevated” are our high quality trips to high altitudes.

People ask me all the time, “Is traveling at high altitude safe?”

My answer is:  Yes!  If you acclimate slowly (which we do on our trips( and do everything you need to adequately prepare before hand.  Here are some tips from an article by Dr. Paul Anderson, an expert on high altitude medicine, on how to travel well in altitude and what to do if you should encounter mild to sever altitude sickness…


What is High Altitude? What elevations are we actually talking about?

High Altitude – (1500m-3500m/ 4921-11,483 ft) – this is where most of our Elevated Trips adventures go, with the exceptions to some trips to Everest Base Camp region

Very High Altitude – (3500m-5500m/ 11,483 – 18,045)

Extreme Altitude – (>5500m/ >18,045ft)


Preparing for Safe Travel to High Altitude

By Paul Anderson, M.D. Co-investigator – ASAP study

Millions of people travel to high-altitude every year for recreation and for work. Twenty percent of those traveling to altitudes below 5500 m/18,000 ft are affected by some form of altitude illness. This number rises to fifty percent above 18,000 ft. While most cases of altitude illness are mild and self limiting, some cases can become life threatening. If you are planning a trip to altitudes above 1500 m/5000 ft. knowledge is the best prevention for altitude illness. This brief outline serves as merely an introduction to this important topic. Additional resources available at the end of this page (or links provided elsewhere in this website) are highly recommended reading for those traveling to high altitude.

Altitude Related Illnesses

High Altitude Illnesses (HAI) include Acute Mountain Sickness (AMS), High-Altitude Pulmonary Edema (HAPE), and High-Altitude Cerebral Edema (HACE). The symptoms of AMS are typically felt by most people when they arrive at a new altitude, but the symptoms are usually self limiting (e.g. 1st 3-5 days at high altitude). The exact mechanisms of AMS remain unclear, however symptoms tend to be the most prevalent 1-2 days after arrival at elevation. The most common symptoms include a headache, gastrointestinal upset, feelings of fatigue, dizziness, and sleep disruption. The more life threatening condition of HAPE includes symptoms of shortness of breath at rest, persistent coughing, exercise intolerance, and possibly the production of pink frothy sputum. HACE is defined as the presence of AMS symptoms with difficulty walking (ataxia), mental status changes, or severe lethargy. If you notice any of these symptoms in yourself or a member of your group, it is critical to stop and evaluate your situation. Descent is usually the first priority when altitude illness occurs.

What General Health Precautions should I take before traveling to High Altitude?

During decades of research, altitude physiologists have identified fairly reliable prevention strategies for avoiding altitude illnesses. However, individuals who perform well on one outing at a given altitude may become ill on another venture to a similar climate. If you are planning to travel to High Altitude there are certainly some general health precautions that will reduce your chances of experiencing a high-altitude syndrome like AMS, HAPE, or HACE.

Get Organized—Plan your trip itinerary to allow for proper ascent schedules. If you are planning a vacation (e.g. skiing or trekking), allow for an extra day or two during the trip so that members of your group can adjust to the effect of new altitudes. For those planning strenuous alpine ascents, remember that difficult terrain can frustrate attempts to adhere to ascent schedules and terrain and weather can severely limit evacuation options. These factors must be included in your plan. Again, descent forms the primary treatment for most altitude illness, so consider egress routes when planning more challenging ascents. Regardless of your location, give some consideration to what you will do if you or a member of your party becomes ill from altitude.

Get Fit—Being physically fit is not regarded as a preventative factor by most experts in altitude physiology.  Even the most highly trained athletes suffer the effects of altitude illness. Nevertheless, if you are physically fit you stand a better chance of being more resilient in the midst of any illness. If you are required to participate in your own rescue or the evacuation of another team member, you will likely be much more effective if you are in excellent physical shape.

Get Checked Out— A visit to a medical provider familiar with the demands of altitude travel is helpful before your trip, especially if you have ongoing medical conditions. You should address any acute medical issues such as sinus infections, bronchitis, or chest pain with your doctor before you leave on your trip. Individuals with Heart and Lung disease should be examined carefully as altitude places tremendous strain on the cardiovascular system. Sleep disorders can also pose significant problems at altitude since sleep is significantly disrupted during the acclimatization process. Musculoskeletal conditions can also present problems for traveling efficiently and performing effectively at altitude. A clinician who knows your health conditions and understands the demands of altitude can help you prepare for your trip. Medications useful to you at altitude as well as immunizations for travel to remote areas can also be provided at your pre-trip visit.

Get Hydrated—Dehydration decreases the body’s ability to acclimatize to high altitude. Unfortunately many travelers arrive at their destination dehydrated after long plane-flights, bus trips, or automobile journeys. Excessive caffeine and alcohol ingestion are common during travel and produce a general state of low blood volume. Even before your trip begins, drinking 2-3 liters of water per day can prepare your body for arrival at higher elevations. Keep a 1 liter water bottle with you when traveling and drink as regularly as is feasible, given your mode of transportation. Reducing caffeine and alcohol consumption before your trip will also decrease your chances of arriving at altitude in a dehydrated state.

Get Medications—You should be sure to have an adequate supply of your regular medications when you begin your trip. While most travelers choose to acclimatize to altitude naturally, many people choose to take prescription medications that help the body adjust to high altitudes, such as acetazolamide (Diamox) and dexamethasone. Others suggest supplements such as gingko balboa may be helpful. The specific benefits of these medications/supplements and their side effects are discussed below. Altitude medications are more highly recommended for rapid travel (i.e. by plane) to very high altitude (3500m-5500m/ 11,483 – 18,045 ft) and may not be required for travel to lower elevations.

Get Rested—Domestic and international travel itineraries often disrupt normal sleep schedules and generate feelings of fatigue. Arriving tired and dehydrated at altitude creates room for altitude illness to develop if travelers immediately begin high-exertion activities such as skiing, hiking or climbing. Many travelers find medications such as Zolpidem (Ambien) helpful if they struggle to sleep while traveling to the start of their trip. Alternatively, plan a rest day or two once you arrive at your destination

Get Educated—The best treatment for altitude illnesses is to avoid getting sick in the first place. While there is no flawless way to prevent altitude sickness, most experts agree that knowledgeable travelers are less likely to experience serious conditions such as HAPE and HACE. You should know the symptoms, ascent guidelines, and treatment methods for altitude illnesses. You can also carry with you small books on mountain first aid that have excellent sections on altitude illnesses. Most individuals who have problems at altitude either lack basic knowledge about high-altitude regions, ignore/rationalize away obvious symptoms, or fail to provide the proper treatments for party members who become ill.

What Medications are Effective in Preventing High Altitude Illnesses?

Prevention: Recent consensus statements on the strength of evidence for various preventive medications are available through the internet. Please see the link below for excellent references and one recent summary article. What follows is a summary drawn from this helpful consensus article.

For further reading, health related professionals may wish to investigate the excellent references at the end of the document.


1. Acetazolamide:

Fairly effective in preventing many cases of altitude illness. The indications for using Acetazolamide include a) rapid ascent to sleeping elevations > 3000 m, b) significant gains in elevation during an expedition (e.g. moving from 4000 m to 5000 m, and c) previous difficulty during travel to high altitude. Acetazolamide has side effects that many find unpleasant causing some travelers to avoid this medication. Consult with your prescribing physician before taking this medication.

2. Dexamethazone:

Dexamethazone has been shown to be effective in preventing altitude illness in many individuals. Some will take it in conjunction with Acetazolamide, or alone. Consensus statements indicate that this medication should be reserved for individuals who cannot tolerate Acetazolamide.

3. Other medications:


Methazolamide, Spironolactone, Nifedipine (useful in treating HAPE, not in preventing AMS) and Sildenafil all seem to have some beneficial effect in some altitude travelers, but scientific research has yet to affirm them as strongly as Acetazolamide and dexamethazone.

Are there any natural supplements that help prevent Altitude Illness?

Gingko Bilboa has been shown to improve circulation and reduce blood pressure in a similar way to Sildenafil (Viagra). Studies have not demonstrated that Gingko is any better than placebo, but some individuals still find this a helpful herbal agent in preventing altitude illness

Other recommendations include high doses of Vitamin C and other anti-oxidant agents which may help reduce the circulating volume of free radicals during acclimatization. Scientific evidence for these interventions is somewhat limited, yet these vitamins may function as excellent support for the irregular diet and lifestyle produced by many travel itineraries.

Some substances controlled in the United States may alleviate the symptoms of altitude illness. Coca leaves (coca de mate) are commonly used to make tea or are chewed directly by many high altitude workers and travelers in Central and South America. These remedies are consumed at the travelers own risk.

One fine summary of herbal remedies exists at:


What Guidelines Exist for Safe Travel in High Altitude Regions?

Group Travel: Traveling with a group is an excellent way to reduce the likelihood of altitude illness. Solo travelers may have a more difficult time recognizing AMS symptoms in themselves and may be more likely to rationalize away their symptoms in order to reach a goal. The use of a buddy system (each member of your group has a buddy to watch them throughout the day) is very effective in recognizing AMS symptoms early. While groups increase the number of people who can potentially become ill, they probably decrease the likelihood that serious illness will occur.

Gradual Initial Exposure: Graded ascent to high altitude is preferred over rapid exposure to high altitude. For example, trekking to elevations over 3500 m over a number of days decreases your risk of AMS when compared with flying to the same elevation. Ascend to altitude slowly when possible. If you are rapidly exposed to altitudes > 3500 m (e.g. LaPaz, Bolivia) consider taking Acetazolamide according to accepted therapeutic regimens. Once you arrive at 3500 m, you should take 2-3 days to rest and allow your body to adjust to the new altitude. This involves non-strenuous activities like walking, touring the local town, or sightseeing.

See the linked YouTube video for more on these acclimatization schedules.

Ongoing Exposure: After 2-3 days spent at altitudes around 3500 m, travelers should increase their sleeping elevation no more than 600 m per day. Gaining more elevation during the day is acceptable so long as overexertion is avoided and the sleeping elevation does not exceed 600m. In addition, an extra night of acclimatization is recommended every 300-900m gain in sleeping elevation. As noted, terrain may frustrate adherence to these schedules, but groups must make their best attempts to approximate these guidelines. (excellent)

What Should I do if someone gets Altitude Illness?

Most healthy people will sustain some mild measure of altitude illness on arrival at altitude, such as a headache, problems sleeping, mild shortness of breath, or fatigue. If these symptoms fail to resolve with a rest day, hydration, and over the counter medications, your group must pay attention, and perhaps initiate treatment.

Treating severe AMS (Acute Mountain Sickness)

1. Discontinue ascent and rest.
2. Acetazolamide 125 mg by mouth every 12 hours until symptom free
3. Dexamethasone 4 mg by mouth every 4-6 hours for two doses. Do not continue ascent until after 18 hours after the last dose and symptom free. This can be used by itself or with Acetazolamide.
4. Give Oxygen, if supplemental oxygen is available.
5. Descend if symptoms persist more than 24-48 hours or if the patient’s condition worsens.

Treating HAPE (High-Altitude Pulmonary Edema)

1. IMMEDIATE descent (almost always with assistance) is imperative, and should not be delayed unless descent poses a greater danger to the parties involved (i.e. weather, terrain). Even modest elevation losses can be helpful.

2. In addition to descent, administration of dexamethasone 8 mg IM/PO loading dose followed by 4 mg IM/PO Q 6 hours should be given immediately.