What harm does it do to your health all the year round on the Qinghai-Tibet Plateau?

Plateau has a special natural environment, which is characterized by low pressure, low oxygen, dry and cold climate, high wind speed, and obviously increased solar radiation and ultraviolet radiation. A recent study by Yang Guoyu, the Mental Health Education Center of the Third Military Medical University, entitled "The Influence and Protection of Plateau Hypoxia on Psychological Function" shows that under the plateau environment, with the elevation, the partial pressure of oxygen in the air decreases continuously, and if people stay in this hypoxic environment for a long time, severe hypoxemia may occur. Because human nerve tissue is the most sensitive to the changes of internal and external environment, under the condition of hypoxia, the brain function damage occurs earliest and the damage degree is more serious, and the longer the exposure time, the more serious the damage, especially the impact on cognitive functions such as feeling, memory, thinking and attention is significant and lasting.

The researchers found that the effect of altitude hypoxia on human sensory function appeared earlier, and vision was the most sensitive to hypoxia. At an altitude of more than 4,3 meters, the night vision is obviously impaired, and this damage will not be improved due to the compensatory reaction of the body or the reduction of altitude. The hearing function of human body will also be affected with the increase of altitude. At about 5, meters above sea level, people's high-frequency hearing will be reduced, from 5, to 6, meters, people's middle-frequency and low-frequency hearing will be significantly reduced, and the directional ability of hearing will also be obviously affected, which may also be an important reason for accidents under hypoxia conditions at high altitude. In addition, the sense of touch and pain of the human body will gradually become dull during severe hypoxia, and illusions and hallucinations may occur at extreme heights.

In the aspect of memory influence, because memory is extremely sensitive to hypoxia, people's memory begins to be affected when the altitude is 18 ~ 24 meters. There is a weak memory around 5 meters, and at this time it is impossible to remember two things at the same time; In the future, with the increase of altitude and the aggravation of hypoxia, it will show different degrees of memory damage, from memory decline to complete loss of memory ability. Researchers believe that memory impairment may be related to the functional changes of the cholinergic system in the hippocampus in the brain. Hypoxia mainly affects short-term memory, but generally does not affect long-term memory.

Acute altitude hypoxia will seriously affect people's thinking ability. At an altitude of 15 meters, people's thinking ability began to be damaged, which showed that the newly learned ability of complex intellectual activities was affected; At 3 meters, the thinking ability in all aspects declined, especially the judgment. At 4 meters, poor handwriting, blunt sentences and grammatical errors; Over 7 meters, a considerable number of people can suddenly lose consciousness without obvious symptoms. Researchers believe that the danger of hypoxia on thinking ability lies in the contradiction between subjective feeling and objective damage. For example, lack of oxygen has caused significant damage to the individual's thinking ability, but he often doesn't realize it, and he won't notice it when he does something wrong. He also thinks that his thinking and working ability are "normal". In addition, people's attention will be obviously reduced during acute altitude hypoxia. When the altitude is above 5 meters, it is difficult to concentrate, and they can't concentrate on doing one thing as usual. Moreover, with the increase of altitude and the aggravation of hypoxia, the scope of attention will become narrower and narrower.

The researchers pointed out that the special environmental characteristics of the plateau have obvious influence on the physiological and psychological activities of the body. The best way to combat hypoxia is oxygen supply, such as providing simple portable oxygen supply devices for people who enter the plateau for the first time, which will help to minimize the risk of cognitive decline caused by hypoxia. People have an adaptation process to hypoxia, which usually takes 1 ~ 3 months. Therefore, before entering the plateau for the first time, it is best to be exposed to different heights in a planned and intermittent manner, so that the body has enough time to compensate for environmental changes, so as to alleviate and eliminate various symptoms caused by hypoxia.

How much do you know about plateau hypoxia

Tibet Plateau is known as the roof of the world. The air on the plateau is thin and there is less oxygen, which greatly affects the normal breathing of human beings.

because the air density decreases with the increase of height, that is to say, the higher the altitude, the lower the air pressure. In order to facilitate calculation, the conversion relationship between air pressure and altitude obtained from meteorology is used, and the average value of 76mm mercury column is used to represent sea level pressure, so as to calculate the percentage of air pressure at each altitude to sea level pressure, which is the percentage of oxygen content at this altitude to that in the plain.

Lhasa is 3,649 meters above sea level, with oxygen content accounting for 64% of the plain, and Shiquan River is 4,278 meters above sea level, with a percentage of 59%; Naqu is 457 meters above sea level, accounting for 56%.

coping measures for altitude sickness (high nutrition)

1. Environmental characteristics of the plateau

1. Hypoxia

From the sea level to the altitude of 1, meters, the content of oxygen in the air is 21%. However, the air pressure decreases with the increase of altitude, which leads to thin air, so the oxygen pressure also decreases. It is estimated that at an altitude of 427 meters, the oxygen pressure is only 58% of the sea level. Therefore, although the relative proportion of oxygen in the atmosphere has not changed, the absolute amount of oxygen has become smaller because of the thin air, which leads to hypoxia.

2. Cold

According to meteorological measurement, the temperature will drop by 1 degree every 15 meters above sea level. Generally, the temperature drops by 6.5 degrees every 1 meters above sea level. Therefore, the temperature in the plateau area is colder than other areas at the same latitude.

3. Low humidity

The low humidity in the plateau increases the water discharged by the human body. According to estimates, the water discharged through breathing on the plateau every day is 1.5 liters, and the water discharged through the skin is 2.3 liters, which is twice the sum of all body fluids discharged from the human body in the plain area at the same latitude without including sweating.

4. Strong sunlight radiation

At an altitude of 3,6 meters, the ionizing radiation, ultraviolet intensity and skin penetration in the universe are three times that at sea level. In addition, the reflection of these rays through the snow is also very strong. According to the measurement, snow can reflect 9% of ultraviolet rays back to the ground surface, while the reflectivity of grassland is only 9%-17%. In other words, due to the effect of accumulated snow, the human body will suffer from double radiation of ultraviolet rays.

the environmental characteristics of the plateau are really extraordinary. In this regard, the human body is not passively coping, but should make corresponding adjustments according to the environment. For short-term tourists, the adjustment is temporary, while people who have been living on the plateau for thousands of years have already formed adaptive changes. Let's see what changes people will undergo in the plateau area.

1. Two hours after the blood system

entered the plateau, due to the lack of oxygen, the body began to produce too many red blood cells to adapt to the anoxic environment, and the hemoglobin increased by 1.1 grams per week. After about 6 weeks, the hemoglobin of the body will increase to 1.4 times the original level, that is, about 2 grams. This phenomenon of hyperhemoglobin is very common in plateau areas, but after returning to low altitude areas, hyperhemoglobin will gradually return to its original level, and mild anemia will appear after 3 weeks of continuous decline. Then the hemoglobin level will rise to normal. Therefore, it is not appropriate to return to the plateau about one month after returning from the plateau to the low altitude area, otherwise, people in anemia are more likely to get altitude sickness.

2. Respiratory system

Due to the low oxygen pressure, the human body will hyperventilate and ventilate due to lack of oxygen. In the quiet state of sea level, the human body needs 25 ml of oxygen per minute, that is, 5 liters of air must be inhaled for gas exchange in the lungs. At an altitude of 3 meters, the human body must inhale 7.5 liters of air to meet the body's need for oxygen. At this time, people will feel short of breath, and if they add exercise, they will feel even more exhausted.

However, living on the plateau is beneficial to the control of chronic bronchial asthma, which is similar to the principle of low-pressure oxygen chamber used to treat bronchial asthma, equivalent to the pressure in the area of 2-25 meters high. The plateau has four distinct seasons, low humidity, high ozone content in the air and high solar radiation intensity, which are beneficial to the rehabilitation of asthma patients. In fact, local residents rarely suffer from respiratory diseases.

3. circulatory system

due to lack of oxygen, tourists' general emotional excitement and slight exercise will make their hearts beat faster. When you first arrive at the plateau, your morning pulse (the pulse when you wake up in the morning) is about 2% higher than the sea level. After 1 days, the morning pulse should drop to the original level. Therefore, by measuring the change degree of morning pulse and the time to return to the original level, we can judge the adaptability of human body to plateau. The incidence of coronary heart disease, arteriosclerosis, hypertension, diabetes, obesity and other diseases in plateau area is very low, and the blood cholesterol and triglyceride levels of local people are also very low.

4. Immune system

In plateau environment, T lymphocytes, which play an important role in human immunity, will be damaged, making the body very vulnerable to bacterial infection.

5. Reproductive system

When the male is at an altitude of 4,3m, the number and mobility of sperm are obviously reduced, and the abnormal sperm are increased. But don't worry, it's only temporary. When we return to low altitude, this phenomenon can gradually return to normal.

The incidence of dysmenorrhea and menstrual disorder increases when women are at an altitude of 43m. Spontaneous abortion, premature delivery and congenital malformation are very common, which is one of the reasons why the birth rate of the population in snowy plateau has been relatively low. Of course, these situations are not a problem for tourists.

Third, learn about altitude sickness

After entering the plateau area, the human body will make corresponding adjustments according to environmental changes. However, the short stay of tourists will limit the adjustment range of human body, so altitude sickness may still occur. The following are the key points to identify altitude sickness. Remember, once you find that you may have altitude sickness, the first thing to do is to go to the hospital quickly. Many altitude sickness are very dangerous and must be treated in time.

1. Acute mountain sickness

most often occurs on the first and second days of entering the plateau above 33 meters above sea level, especially in the first 6-9 hours of the first day.

identification points: headache, plus any of the following symptoms: general fatigue, dizziness, insomnia, nausea and vomiting.

2. High altitude pulmonary edema

The mortality rate of untreated high altitude pulmonary edema is 4%.

identification points: those who have two or more of the following conditions: dyspnea at rest, cough, weakness and decreased activity, feeling of blockage in the chest, pale and cyanosis skin, and increased heart rate.

3. Alpine brain edema

The mortality rate of untreated alpine brain edema is 14%.

identification points: having symptoms of acute mountain sickness, unable to walk in a straight line, and having mental abnormality.

4. Chronic altitude sickness

refers to the maladjustment to the plateau environment after a period of adaptation.

identification points: fatigue, headache, dizziness, cyanosis, lack of endurance during exercise, etc.

5. Others

At different altitudes, tourists may have the following symptoms:

15m: their eyesight is weakened in the dark.

15-18 meters: the advanced thinking function is weakened or lacking.

33m: Simple arithmetic becomes very difficult.

46 meters: writing and thinking are affected.

above 55m: 1% of tourists will suffer from laryngitis and tracheitis.

4. Preparation before entering the plateau

1. From the day you decide to travel to the plateau, you should increase the time of anaerobic exercise in your daily life. Anaerobic exercise refers to strenuous exercise with a large amount of exercise, which can make the body have a certain tolerance to hypoxia.

2. Prepare some commonly used medicines. In plateau area, the respiratory system is very susceptible to infection, and antibiotics such as amoxicillin and roxithromycin should be brought. The sanitary conditions in the plateau are limited, and it is easy to suffer from gastroenteritis. You can bring ciprofloxacin or sulfonamides. It is also necessary to prepare acetazolamide, a diuretic, which is the main drug to prevent and treat altitude sickness, and can eliminate paroxysmal nocturnal apnea, improve the quality of nighttime sleep, and reduce the headache when getting up in the morning. Administration method: 125mg twice a day, or 25mg once a day. Take it 24 hours before entering the plateau.

3. The temperature difference between morning and evening in plateau area can reach 15-2 degrees, so you need to bring enough cold-proof clothes.

4. prepare protective articles against ultraviolet rays.

5. If you fly directly into the plateau area, you should get enough sleep one night before sailing in the low altitude area, and don't eat greasy food or drink. If you enter the plateau area by car or train, you should make a good daily trip plan, and it is best to control the rising height at 4-6 meters every day. Every time you reach a new height, you should rest for a few days, so that your physical strength can gradually recover and adapt to the hypoxia environment on the plateau. If you are hiking or riding a bike, you should ask experts to make a scientific climbing plan in advance according to your physical condition.