Altitude sickness, also called acute mountain sickness (AMS) and altitude illness, is a disorder caused by being at high altitude where air pressure is low without prior acclimatization (the process of gradual exposure). It is the body's reaction to a lack of oxygen, caused by ascent at a faster pace than acclimatization.
Rising to higher altitudes can also cause fluid to leak from tiny blood vessels (capillaries), resulting in potentially dangerous fluid accumulation in the lungs and/or the brain. If a human continues rising to higher altitudes without adequate acclimatization, there is a serious risk of life-threatening illnesses such as High Altitude Cerebral Edema and High Altitude Pulmonary Edema.
Go up to the sky of 100,000m, the oxygen averages 21% in air. However, the air pressure will be decreased with higher altitude, which leads thin air and lower oxygen pressure. According to the tests, the oxygen pressure is only 58% in altitude of 4270m than it in sea level. Therefore, there is not any change of relative quality of oxygen in atmosphere, but the absolute quality of oxygen is decreased due to the thin air. People will suffer Acute Mountain Sickness in this environment.
According to the atmosphere testing, the temperature will be decreased 1? per 150m ascending. In general, per 1000m ascending of the altitude, the temperature will decrease 6.5?. Therefore, plateau is always colder than other places with the same latitude.
It is lower humidity in high altitude; much water is discharged of our body. According to testing, our body discharges water of 1.5 liters by breathing per day in plateau. Our body discharges the water of 2.3 liters through skin per day.
In high altitude of 3600m, the ultraviolet radiation is three times as it in sea level.