High Altitude Sickness

Traveling in a higher altitude is certainly full of adventurous and fun. Whether it's a 4 WD adventures or trekking or mountaineering, the views from the top are just great! The landscapes are picturesque but there are also risks of going to such places. So, it's very important for you to know what a high altitude is and what the symptoms, its prevention and remedies are.

How to avoid high altitude sickness when camping on Mount Everest in Nepal

What is a High Altitude Sickness?

High altitude sickness is also called Acute Mountain Sickness (AMS). The following are the preliminary symptoms likely to occur. But the first four symptoms are likely to be experienced by any traveler during first few days in a high altitude and later you will get acclimatized, if you follow the precautionary measure.

  • Breathlessness or irregular breathing.
  • Dizziness.
  • Disorientation.
  • Weakness, fatigue, lassitude and heavy legs.

If the above symptoms persist or further deteriorate as described below, you really have to stop going ahead and descend immediately to a lower altitude.

  • Persistent Headache.
  • Loss of appetite and weird dreams.
  • Less urine output.
  • Slight swelling of hands and face.
  • Nausea and vomiting.

How high is called "High Altitude"?

Altitude grades are defined as below.

  • High: 8,000 to 12,000 feet.
  • Very High: 12,000 to 18,000 ft.
  • Extreme High: 18,000 and above.

What are the reasons of the High Altitude Sickness?

The main reason of the sickness is the rapid ascent to a higher altitude without proper acclimatization. Rapid ascent means gaining 1000m (3,280ft) or more on a single day. Higher altitude has the deficiency of oxygen level. The oxygen level is the highest in the sea level but as the altitude increases, the number of oxygen molecules available per breath is reduced. At 12,000 feet, the oxygen volume decreases by 40% than in the sea level. In order to properly supply the oxygen to your body, your breathing rate (even while at rest) has to increase. This extra supply of oxygen in your body may increase but not to a sea level concentration. Since the amount of oxygen required for the metabolic activities of our body is the same, the body must adjust to having less oxygen. In addition, for some reasons beyond understanding, 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. As your body may not be adapted to the low supply of oxygen, you will start feeling the symptoms of the sickness and continuing to higher altitudes without proper acclimatization can lead to potentially serious, even life-threatening illnesses.

Who are the victims of the High Altitude Sickness?

There are no clear-cut factors such as age, gender, or physical condition that correlate with the vulnerability to altitude sickness. Some people are more vulnerable while others are not. We would rather say that the chance is almost equal to everybody but you can prevent it or minimize it if you follow the precautionary measures. But certainly, those who are physically weak or have low fitness level, heavy smokers or drug users, the patients of pulmonary and cardiac complaints and those who have never been to a higher altitude before have more chances of getting the sickness. That being said, there has also been a case when our highly experienced mountain guides have fallen sick sometime. One of our experienced trekking guides was caught sickness in Gyantse and shockingly it was his second time within the same year! So, it's only the matter that how careful you are in following the preventive measures.

How to minimize the chance of getting altitude sickness?

You can minimize the chances of getting altitude sickness in three levels.

Physical training at least 2 months prior departure to Tibet

If you do not follow any regular physical exercises, you have to start right away as you start on working on your itinerary. Simple exercises like 1-2 hours walking, jogging, biking or swimming or health club exercises will keep you fit and help build stamina on your body. If possible, stop smoking and drinking alcohol. Have your blood pressure level checked and consult the physician if you have any kind of cardiac and pulmonary complaints.

Proper acclimatization

As mentioned earlier, the major cause of altitude illnesses is going too high too fast. If you take it easy and allow time, your body will adapt to the deficiency of oxygen molecules at a specific altitude. This process is known as acclimatization and generally takes one to three days at that altitude. Here are some tips how you can get acclimatized.

Make sure you have a good sleep the night before you fly into Lhasa or enter Tibetan plateau. If possible, avoid flying or driving to high altitude. Start below 10,000 feet and walk up. If you fly or drive, do not over-exert yourself or move higher for the first 24 hours. If you go above 10,000 feet, do not exceed your altitude gain more than 1,000 feet per day and for every 3,000 feet of elevation gained, take an extra rest day. After getting off the plane, walk slowly, take some deep breath. Do not do anything exertive.

"Climb high and sleep low." This is the maxim used by climbers. You can climb more than 1,000 feet in a day as long as you come back down and sleep at a lower altitude. If you begin to show symptoms of moderate altitude illness, don't go higher until symptoms decrease. If symptoms persist or increase, go down, down, and only down and also stay 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 litres per day, sip by sip, of course no lit liquor!). Urine output should be copious and clear.

Avoid tobacco and alcohol and other depressant drugs including, barbiturates, tranquilizers and sleeping pills. These depressants further decrease the respiratory drive during sleep resulting in a worsening of the symptoms. Eat a high carbohydrate diet (more than 70% of your calories from carbohydrates) while at altitude. Keep munching energy bars, chocolates etc, as they will help you maintain energy level in the body. The acclimatization process is inhibited by dehydration, over-exertion, alcohol and other depressant drugs.

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 an altitude and continue for at least five days at higher altitude. The recommendation of the Himalayan Rescue Association Medical Clinic is 125mg and twice a day (in the morning and night) but you are recommended to consult your physician for the prescription.


(A steroid). This is a prescription drug that decreases brain and other swelling reversing the effects of AMS. Dosage is typically 4mg twice a day for a few days starting with an ascent. This prevents most symptoms of altitude illness. It should be used with caution and only on the advice of a physician because of possible serious side effects. Other medications for altitude illnesses is Ibuprofen which is effective in relieving altitude headache. Nifedipine rapidly decreases pulmonary artery pressure and relieves HAPE. Breathing oxygen reduces the effects of altitude illnesses.

Pressure Chamber or Gamow Bag

The bag is simply a sealed chamber with a pump. The patient is placed inside the bag and it is inflated. Pumping the bag full of air effectively increases the concentration of oxygen molecules and therefore simulates a descent to lower altitude. Keeping the patient 10 minutes in the bag can create an atmosphere that matches to that at 3,000 - 5,000 ft lower. After, 1-2 hours in the bag, the person's body chemistry will have "reset" to the lower altitude. This lasts for up to 12 hours outside of the bag which should be enough time to walk them down to a lower altitude and allow for further acclimatization. We send a Gamov bag in each Mount Kailash trips and other higher altitude trekking.

Garlic Soup cures the altitude sickness!

The famous Sherpa guides of Nepal serves garlic soup to the patient to cure the sickness and the patient later says "It really helped". This is something the specialists have to research.


The information provided here is for general knowledge only and not in any case can be used as the substitute for specific training or experience or medical consultation. We assume no liability for any individual's use of or reliance upon any material contained or referenced herein.