Altitude Sickness Information

When trekking in the Himalayas there is always the danger of mild to serious problems related to the high altitude. The symptoms are communally known as Acute Mountain Sickness (AMS).

Failure of the body to acclimatize to the reduced amount of oxygen available above the elevation of 2400-2500m is known as AMS. It is important that trekkers understand they will be affected to a greater or lesser extent when they ascend to over these altitudes. As you climb higher, the atmospheric pressure falls and the amount of available oxygen also decreases. The body will adjust to cope with this by altering the characteristics of your blood in order to utilize better the lower oxygen levels available to it. This process takes time and can differ from individual to individual. In fact, individuals can experience different rates of acclimatization on separate visits. So, having acclimatized well on a previous visit, there is still no guarantee of subsequent quick acclimatization.

The mechanics of acclimatization are not well understood but it has been proved that a number of factors have a positive effect. By far the most important is regulating your rate of ascent when traveling in excess of 2500 meters above sea level. As a general rule, you should not gain more than 300-400 meters a day and have a rest day every third to fourth day. Maintaining good fluid intake and urine output has also been proven to be effective in combating the effects of altitude. The dry air of the mountains tends to dehydrate you so an increased fluid intake. Try to drink at least four liters of well-purified water a day.

Prophylactic medication should not be required to aid acclimatization unless specifically prescribed by a physician skilled in the treatment and prevention of altitude sickness. Fitness may have some effect on speedy acclimatization but being young and fit does not guarantee immunity. The only age concern is for the very young who may not be able to describe their symptoms to their parents. For this reason, it is unwise to take very young children to altitudes above 3500 - 4000 meters. Symptoms of AMS may be mild or severe and the victim can develop severe symptoms very rapidly if the mild effects are ignored.

The initial symptoms of AMS are as follows

# Nausea, vomiting
# Loss of appetite
# Insomnia/sleeplessness
# Persistent headache
# Dizziness, lightheadedness, confusion
# Disorientation, drunken gait
# Weakness, fatigue, lassitude, heavy legs
# Slight swelling of hands and face
# Breathlessness and Breathing irregularity
# Reduced urine output
# Irritability & weakness
# Sleep disturbance

All or some of these symptoms may be present in mild cases of AMS but they can rapidly worsen and become dangerously debilitating. In particular, as the symptoms worsen the victim will often become irrational and difficult to reason with. Their ability to make sensible decisions for themselves is increasingly impaired and their companions may be their only hope of survival. This is a compelling reason for never trekking alone at high altitudes.
In the final stages of altitude sickness, severe problems start to appear which can rapidly lead to loss of consciousness and death if untreated. Two forms of AMS are generally recognized. One or both may be present and either extremely serious.

High Altitude Pulmonary Edema (HAPE)

HAPE is caused by an accumulation of fluid in the lungs. As it progresses, more and more fluid builds up until the victim literally drowns. The symptoms include difficulty breathing and rapid pulse rate even at rest, coughing pink, frothy sputum, and occasionally blueness around the lips.


*Severe headache
* Repeated vomiting
*Blurred & double vision
*Abnormal behaviors
*Sleep disturbance
*Less urine output

High Altitude Cerebral Edema (HACE)

HACE is the most serious of the forms of AMS and is caused by a buildup of fluid around the brain. The previously mentioned symptoms of mild AMS rapidly worsen, particularly the headache along with slurring of speech and ultimately unconsciousness and death. The advance of the problem can be very rapid and death can occur in 12 hours if treatment is not given in time.
If you follow the simple advice of our trained guides, you won’t have to worry about complications from mountain sickness. We design all our tours to ensure that clients are ready for high altitudes and arrange alternative itineraries for those at risk.


  • Chest pain
  • Cough with plenty of sputum & blood
  • Difficulty in breathing during rest
  • Sleep disturbance
  • Less urine output
  • Blue lips/thong’s apex  

The Best Treatment for AMS is Prevention

The following points are very important for preventing the AMS.

  1. Awareness about AMS.
  2. Go up slowly. While walking above 2500m elevation, ascend 300m per day.
  3. Take rest 1 day after every 3 to 4 days walking.
  4. Drink a lot of fluids (3 to 4-liter water per day).
  5. Avoid hypothermia.
  6. Do not carry more than 10 kg in your pack.
  7. Do not use alcohol, sleeping tablets, or smoke.