The sickness which occurs during the ascension of the High altitudes is called AMS which is normally experienced above the 2800 mtrs from sea level. In the Himalaya it is believed that if we do not take certain precautions, we have a high possibility to experience the symptoms which is from mild headache, dizziness, fatigue, shortness or breath, loss of appetite, nausea, disturbed sleep, and a general feeling or malaise. Symptoms are generally starts from 10 to 13 hours after arrival at that altitude and begin to decrease in severity about the third or fourth day

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 3,658 meters, the barometric pressure is only 483 mmHg, so there are roughly 40% fewer oxygen molecules 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 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.

The altitude sickness is common in the high altitude due to the imbalance of the oxygenate air as well as due to the irregular breathing and blood circulation so we all have to take proper measurements and precautions before it arrives to the fatal situation. There are several methods to prevent and to minimize the problems:
-Do exercises to keep you good healthy condition before coming to high altitude,Avoid catching a cold and flue,Make sure you did not have any serious problem with heart and lungs,Less activities for the first several days, walk slowly, drink more water.Ascend to higher altitude gradually, take a preventie medications such as Diamox. Diamox or Acetazolamide allos you to breath faster so it helps to metabolize more oxygen which is helpful at night when respiratory drive is decreased. As the effect starts after about 24 hours, it is recommended to take in time before you reach altitude and continue about 5 days for higher altitude in a quantity of 125 mg twice a day which is morning and night. Diamox is a sulfonamide drug, which is recommended for not taking by sulfa drug allergic people.Dexamethasone or steroid is another prescription drug that decreases brain and other swelling reversing the effect of AMS which is taken 4 mg twice a day before sometime assension. This prevents most symptoms of altitudesickness which should be taken with caution and only on the advice of physician as it may cause serious side effect.