The Himalaya begins there, where other mountain areas end. The Everest base camp is situated on base of enormous mountains but still three thousand feet higher then the highest mountain of Europe. Your body can acclimatize to this hight after sufficient adaption only. Haste can be deadly in this hight !!

Your body must acclimatize during the ascent. Plane your route like this, that you don't climb higher than 1.000 feet per day, in a hight over 9.000 feet.

If you don't take enough plenty of time, there can occur symptoms of Acute Altitude sickness(AAS). This symptoms can be slight, that ease after a rest of one day but, if you ignore, you can die.

HOW YOU REALIZE THE ACUTE ALTITUDE SICKNESS

AAS can occur in a hight above 6.000 feet. The first symptoms are headache, extreme tiredness and appetitness. Some people get breathness during their rest. AAS cause an accumulation of liquid in parts of the body, that's not for this area: in brain, lungs or both. Is's a warning to stay in the same elevation when mild symptoms appear, until the symptoms are disappeared. Don't climb up with symptoms of AAS ! Mostly within one or two days you will feel better, than you can continue the trek.

If you stay in the same altitude however the symptoms become more heavy, a descent is inevitable. If the symptomes of AAS intensify, for example incrasing tiredness, headache, nausea and lose one's bearings, this are symptoms of brain odems. If you ignore the symptoms you can fall in faint or die within 12 ours. Increasing of breathness, cough and tiredness are symptoms of lungs odems. Also this can be fatal if you ignore.

It's possible, someone who got AAS, he cannot make the right decision and must be forced to descent. Even someone is prepared to descent, never he should descent allone. Go with him until his condition becomes better, normally after a descent of 900 to 1.500feet. If he feels better he can ascent again.

Summary: If you don't feel good in the hight you have probable slight symptoms of Acute Altitude Sickness. Stay in the same elevation if you feel better. If your condition gets worse in same elevation descent to the last village at least where you have felt better.