As we ascend above 2,500m, our bodies have to acclimatize to the decreasing amount of oxygen available. Failure to acclimatize results in acute mountain sickness (AMS). 
 
The onset of AMS is signaled by the symptoms listed under mild AMS. If these symptoms are further neglected then it can develop to HACE (High Altitude Cerebral Edema that is the accumulation of water in the brain) and HAPE (High Altitude Pulmonary Edema that is the accumulation of water in the lungs). But no worries. Our leaders are highly trained to monitor and treat AMS properly. On our high altitude treks and expeditions we do carry a Portable Altitude Chamber and intensive first aid kit as an extra safety precaution. Please follow your leader's instruction if he advises you to descend as this would be the best thing to do. In case of emergency situations, we organize helicopter evacuation. 
 
Proper acclimatization is very important and our routes are planned specifically to allow a gradual gain in altitude with many of our treks having extra days to allow for acclimatization. By slowly gaining height we reap the benefits of a gradual gain in fitness and acclimatization. We offer advice about acclimatization and with the sensible approach we take on all of our treks, anyone who is fit and healthy should be able to cope with it. 
 
The best treatment of AMS is prevention.

• The higher you go the slower your rate of ascent should be
• As much as the terrain and other factors permit, follow these guidelines for safer acclimatization:
• Above 2,500m: 300m of ascent or less per day, with a rest day every three or four days
• Above 4,000m: do not exceed 150m per day, with a rest day every three or four days
• The daily ascent recommended is the difference between sleeping locations. You may go higher during the day as long as you sleep lower down
• Avoid over-exercising and exhaustion while acclimatizing, and especially while experiencing symptoms of AMS
• Avoid dehydration. Keep your urine clear and plentiful by drinking up to four liters of liquid or more per day. Use half strength rehydration solution
• Avoid alcohol and salt
• Avoid medications such as sleeping tablets, sedatives, strong painkillers and antihistamines, which depress the respiration and increase the risk of AMS, especially while sleeping.
• Use the 'buddy system' to keep an eye on each other
• Flying or driving to high altitude increases the risk of developing severe AMS. Consider using Diamox , first dose the day before you ascend, and continue for four or five days

One or a combination of any of the following may occur 

• Headache (often relieved by mild painkillers)
• Dizziness
• Loss of appetite
• Nausea and/or vomiting
• Tiredness, fatigue
• Irritability
• Disturbed Sleep

Rest at the same (or lower) altitude until the symptoms clear (this usually takes one to three days)

• Follow the advice given under prevention in previous page
• Check the victim regularly, especially during the night
• Ensure adequate liquid intake. Keep the urine pale and plentiful
• Use ibuprofen or paracetamol for headache
• If the symptoms of mild AMS persist, especially if the sleep is disturbed, give Diamox 125 to 250 mg morning and night and continue this for four days, or for the rest of the time at altitude if the symptoms return
• Place the victim in a Portable Altitude Chamber ( PAC) if available, for an hour or more until the symptoms clear
• Examine the victim for severe AMS( HAPE and HACE) and repeat the examination if their condition gets worse
• If symptoms become worse after resting at the same altitude or signs of severe AMS appear, descend.