Usually, the plateau above 3000 meters above sea level is called medical plateau in medicine. Plateau scientists define 3000 meters as the critical height of human reaction, that is, "the height that does not harm health." The theme that is not harmful to health is altitude sickness caused by hypoxia, and the harm to human body caused by a series of natural factors such as bottom temperature, strong ultraviolet rays, cosmic particle radiation and low humidity caused by altitude rise.

Altitude that is not harmful to health (without medication. This altitude generally does not belong to the category of altitude sickness): 2000 -2700 meters above has a slight benign reaction to a very small number of people. 2700-3000 meters has a slight adaptive response to some people, and people with critical illness should not enter (it is estimated that they will not toss here).

Altitude harmful to health (drugs can be weakened): 3000-3300 meters has mild to moderate persistent altitude sickness for most people, and some reactions are serious. People with chronic diseases or particularly weak health are not allowed to enter! From 3300 meters to 3600 meters, most people have mild to moderate persistent reactions, and some people have serious reactions. People who are weak and have a family history are not allowed to enter! 3600-4000 meters is moderate for most people. Generally, people under the body should be cautious!

Altitude seriously damaging health: 4,000m-5,000m: all of them have moderate or above reactions. Taking medicine first can reduce them to moderate or mild (depending on physical fitness), and don't be too far away from oxygen tanks. Above 5000 meters is designated as ultra-high altitude, which is the critical height of obstacles and the forbidden area of life. Better be careful and take risks! 7000 meters is a dangerous critical height, and the body above 7000 meters cannot be compensated. It's a dead zone in the mountains, so it's best not to go!