What is Mountain Sickness?

Often starting at an altitude of 10,000 feet, Acute Mountain Sickness (AMS), or altitude sickness, may begin with hangover-like symptoms such as headache and nausea. These initial symptoms generally occur when people ascend too quickly.  It is common to suffer from AMS. For example, at 14,000 ft even after having ascended slowly (ie about 1000 to 1500ft gain in sleeping altitude per day), 30 % of people are stricken by these hangover symptoms.  For most people these symptoms will spontaneously go away after a day or two of rest at the same altitude or, if the symptoms get worse, by descending to a lower altitude.  

Going up too high, too fast has severe, life threatening repercussions.   These complications vary from water in the head - high altitude cerebral edema (HACE) and water in the lungs - high altitude pulmonary edema (HAPE). With HACE you may not be able to walk a straight line and with HAPE you may be short of breath even with minimal exertion. The symptoms may progress from nausea, headache and tiredness to vomiting, lethargy, and finally to coma and death, usually in a few days if  the person does not descend when the symptoms increased.

Dehydration and hypothermia exacerbate the symptoms of AMS.  Danger sets in when someone is in a hurry in the mountains and keeps on ascending in the face of increasing symptoms of headache, nausea and shortness of breath on mild exertion. This is when HAPE and HACE may occur.

How can I prevent Mountain Sickness?

The complications of Mountain Sickness are preventable if people listen to their bodies and follow simple guidelines.

· Pay attention to your body and be aware of the initial symptoms of AMS. Do not ascend with these symptoms.
· Ascend slowly.  Increase your sleeping altitude by only 1000-1500 feet per day.  Try climbing higher during the day and coming down to sleep.  (Climb high, sleep low)
· Descend if the symptoms become severe or if you experience HACE and HAPE.
· Drink 2 liters (2 regular size Nalgene bottles) of water per day in addition to the usual tea and other soft beverages.  This will prevent dehydration, an important potential problem in the Himalayas, which may lead to AMS or mimic AMS. 
· Dress properly for high altitude treks with synthetic under shirts, which unlike cotton shirts does an excellent job in wicking off the sweat; a warm fleece jacket; and a down jacket to prevent hypothermia which can predispose you to AMS and its complications.

The US Embassy-Kathmandu encourages all trekkers to procure emergency evacuation insurance prior to their trip to Nepal.

For further information on prevention and treatment please go to:  www.himalayanrescue.org or visit the offices of the Himalayan Rescue Association.  Kathmandu (Dhobichaur, Lazimpat, north of the Royal Palace, 444-0292 and 444-0293) or  Thamel(444-5505), or/and in Pheriche in the Everest region and in Manang in the Annapurna region.

These organizations are a good source of free lectures and answers for your questions.

Have a safe and enjoyable trek in the Himalayas.