Acute mountain sickness (AMS) is the effect on the body of being in a high altitude environment. AMS is common at high altitudes, that is above 8,000 feet (2,440 meters). Three-quarters of people have mild symptoms of AMS over 10,000 feet (3,048 meters). The occurrence of AMS depends on the altitude, the rate of ascent, and individual susceptibility.
Mild AMS: Many people experience mild AMS during the acclimatization process (the first 1 to 3 days at a given altitude). Symptoms usually start 12-24 hours after arrival at altitude and include headache, dizziness, fatigue, shortness of breath, loss of appetite, nausea, disturbed sleep, and a general feeling of malaise. These symptoms tend to be worse at night when respiratory drive is decreased.
Mild AMS does not usually interfere with normal activity and symptoms generally subside within 2-4 days as the body acclimatizes. As long as symptoms are mild, and only a nuisance, ascent can continue at a moderate rate. When hiking, it is essential to communicate any symptoms of illness immediately to others on your trip. AMS is considered to be a neurological problem caused by changes in the central nervous system. It is basically a mild form of high altitude cerebral edema.
Mild AMS is usually treated with pain medications for headache and a drug called DIAMOX which allows one to breathe faster and so metabolize more oxygen, thereby minimizing the symptoms caused by poor oxygenation. This is especially helpful at night when respiratory drive is decreased. Since it takes a while for DIAMOX to have an effect, it is advisable to start taking it 24 hours before going to altitude and continue it for at least 5 days at higher altitude.
Article By : Ranabir Aditya