Mountain sickness - 高山症

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Mountain sickness (That isAltitude sickness) Is a person's response to low oxygen conditions at high altitudes (due to lower air pressure in high altitude areas). Your body will react in various ways: some are normal reactions, some are sick reactions. A sick reaction is a danger that can seriously affect your health. If you ignore it or don't deal with it, this reaction can lead to your death.

High altitude sickness is very dangerous for four reasons: it can attack suddenly and get worse quickly, which can be fatal; patients are often not close to where medical assistance can be obtained; it is also difficult for patients to evacuate quickly; In many cases, patients depend on their health because they are doing a lot of physical exercise in dangerous environments.

Alpine sickness is a great danger for mountain sports at high altitudes (4000m to 5000m), a danger for mild mountain sports (such as skiing in areas from 3000m to 4000m, especially in Colorado), or a mild Danger-When you fly to high-altitude cities, especially China's Tibet (Lhasa), Peru (Cusco, especially for the Inca Trail), and Bolivia (La Paz). For medium altitudes (for example, 3500m), the main solution is to spend one or two nights adapting to the environment in lower altitude areas (around 2500m), and maintain a more relaxed attitude in the first few days, instead of flying there. Go hiking or skiing immediately. At higher altitudes, you have to be more careful and climb slowly, which is very necessary. Adapt to needstime, If you are too impatient, it will cause mountain sickness.

In high altitude areas, there are other risks, which are not included here. One is that the weather may be very cold: seecold weather. The other is that there may be danger caused by strong sunlight, because the atmosphere above your head is relatively thin, which is not enough to protect you: seeSun protection measures. Finally, the terrain may pose a hazard, such as an avalanche or just falling from a mountain: seehiking。

learn

The farther and higher the sea level, the lower the air pressure. There are two main problems with your body, high altitude and corresponding low air pressure: the lungs get less oxygen in the air with lower air pressure. Your body will produce more red blood cells to transport oxygen, but this process takes several days, sometimes more than a week, and you may get sick at the same time.

• In a lower air pressure environment, water evaporates faster. This may cause youDehydration。

The changes in height at altitude are complex and very eye-catching. Your body’s difficulty in maintaining a good oxygen supply and controlling related problems is directly related to your altitude and recent changes in altitude. These are the two main factors that cause altitude sickness. The height at which you sleep is also important, because most of the red blood cells needed to improve oxygen management are made while you sleep.

Therefore, this article discussed a lot about rising and falling. Moving further away from sea level is a dangerous activity and you must be vigilant at the time. On the contrary, the drop to sea level is the most important factor in reducing or eliminating various forms of altitude sickness. In addition, this article also talks about a lot of knowledge about adapting to the environment, so that your body has enough time to adapt to higher altitudes. This is essential to avoid problems.

How tall is it?

The highest capital in the worldLa Paz

A small number of people (about 20%) will have some symptoms of altitude sickness if they rise to 2500 meters above sea level and sleep there (this is the cabin pressurization level of most commercial aircraft except Airbus A380 and Boeing 787). However, most people will adjust to 3000 meters relatively easily and may develop symptoms after the first night.

It is much more difficult to adapt to an altitude of 3000-5000 meters, here, if you are traveling at a higher altitude, it must slowly rise and return to a lower altitude to fall asleep. More than 50% of people will get sick if they rise quickly from sea level to 3500 meters without adapting to the environment, and if they rise quickly to 5000 meters, everyone will get sick.

It is believed that it is impossible to permanently adapt to altitudes higher than 5500 meters. Once you adapt to the environment, it may take several weeks to sleep up to 6000 meters, but your health will still gradually deteriorate.

The area over 8000 meters is called the "death area": ​​when you stay at such a high altitude, you will deteriorate significantly, some major systems of your body will shut down, and climbers will only stay there for two or three days . The death rate of altitude sickness above 7000 meters is estimated to be as high as 4% of the population.

If your family is significantly above sea level, you can get definite support when ascending to higher altitudes, but this does not protect you from the plateau problem; it just pushes up the threshold for their incidence. Most of the healthy people living at an altitude of 1500 meters to 2500 meters, the altitude range includes quite a lot of major cities, there are few troubles at 3000 meters or higher, but even so, they face the risk of plateau problems at 5000 meters. .

Risk factors

The incidence of altitude sickness in men is higher than that in women, especially men between the ages of 16 and 25. It is not clear whether there are some unknown biological reasons, or it is simply that the population is most likely to try too much exercise prematurely. It is important to remember that just because you are young and healthy and have not experienced altitude sickness in the past does not mean that you will be immune to it in future climbs. Physical health is not necessarily a good indicator, nor is it strength or health. Although you are healthy and young, you may react to altitude. In fact, health, youth, and health have a hidden risk: their general physical ability makes them believe that they should handle height well, which is not always the case.

On the other hand, poor health is a risk factor: especially heart or respiratory diseases. A healthy heart and lungs have enough time to breathe oxygen into tissues at high altitudes. Of course, if you have physical problems that make your exercise difficult, you have reasons to carefully consider exercise in high altitude areas, which will be even more difficult!

divingWill increase the risk of decompression sickness. If you have recently dived and have not completely removed the nitrogen from your blood, you should not ascend to a higher altitude (or travel on an airplane). For advice on waiting time, seediving。

Place

In addition to climbing and other mountain sports, such as skiing. The main tourist destinations at high altitudes are Bolivia, Peru (Bolivia Plateau), and Qinghai-Tibet Plateau (Qinghai, Tibet). All these destinations are about 3,500 meters above sea level. The altitude of these areas makes the probability of altitude sickness extremely high. Other mountain destinations. For example, Mongolia, Nepal, Switzerland (mostly less than 2000 meters), and even Bhutan (about 2500 meters), most of the residents settle in places with lower altitudes, especially in valleys where the risk of altitude sickness is greatest.

In order to fly to Peru to visitInca Trail、CuscoThe altitude (3400 meters) is extremely high. It is dangerous to visit the Inca Trail immediately, which occasionally leads to death. The safer option is to leave Cusco for the Sacred Valley for one or two nights before returning to Cusco. However, Machu Picchu High (2400 meters) This is not particularly high.

Go by planeLhasa, Stay hereKunming(2000 meters) orXining(2300 meters) A few nights can help you adapt to the plateau environment. Taking the train to Qinghai-Tibet is not recommended, and going from low altitude to high altitude will make you unable to adapt to the plateau environment.

Fly toLa PazYou should live in lower elevation towns (such as Karakoto and Obras) for a few days to get used to the plateau environment.

As far as large cities are concerned, there are more than a dozen cities (with a population of at least 100,000) above 3000 meters above sea level, the most famous of which are La Paz (Bolivia, 3650 meters), Lhasa (China, 3650 meters) and Cusco (Peru, 3400 meters) Ecuador, Colombia, Mexico, Eritrea, Ethiopia, Yemen, Guatemala also have 1-3 major cities at an altitude of 2000-3000 meters. There are also some small cities in Afghanistan and India at high altitudes.

List

The altitude of important tourist destinations is relatively high.

North America

• Colorado
  • Many high-end ski resorts, such as Breckenridge (approximately 3,000 to 4,000 meters)
  • Aspen (2,400 meters)

South America

• Bolivia
  • La Paz (3,650 meters)-the capital city with the highest altitude
  • El Alto (4,150 meters)-one of the highest metropolises
• Colombia
  • Bogotá (2,600 meters)
• Peru
  • Cusco (3,400 meters)
  • Inca Trail: Warmi Wañusqa "Dead Women Pass" (4,200 meters), Paguemeyo (approximately 3,500 meters)
  • Machu Picchu (2,400 meters)

Asia

• Bhutan
  • Thimphu (2,250 to 2,650 meters)
• China Tibet
  • Lhasa (3,500 to 3,650 meters)

High impact

Preventive measures for heights reaching 5360 meters

Altitude has some physiological effects on people in all high-altitude areas. These effects are not symptoms of disease in themselves, although they are signs of increased difficulty in the body at high altitudes.

Hyperventilation

At high altitudes, your breathing rate will increase to compensate for the lower air pressure. You may not notice this: a similar effect occurs during air travel.

Increased urination

Increased urine output is the body’s response to hypoxia. Increased bicarbonate output can increase breathing-which will put you in high altitude areas. More urine output. If your urine output is about the same as in low altitude areas, then you are most likely dehydrated.

Breathe regularly

Due to changes in body chemistry leading to interruption of oxygen and carbon dioxide levels in the blood and hyperventilation at altitude, your body’s "when to breathe" chemical signals can become confused. When you are awake, you will remember to breathe, but when you are sleeping, breathing interruptions are very common: hold your breath for up to fifteen seconds, and then breathe very quickly when you start breathing again.

Knowing that you are not breathing or having difficulty breathing can be surprising when you wake up, or when you find that someone else has stopped breathing. But it is a normal response to height, and almost everyone encounters it. Adapting to the environment will only improve it slightly.

Altitude sickness

KilimanjaroClimber on the top-a mountain that can easily and quickly ascend dangerous highlands

In addition to the less dangerous physical effects, altitude makes you susceptible to actual diseases, some of which are very dangerous. Although you cannot avoid all the effects of the plateau, you should take wise measures to avoid the actual disease, and if it does happen, take it very seriously.

Dehydration

You need to increase your fluid intake at high altitudes. A sign of loss of appetite and nausea can lead to dehydration and headaches. Unfortunately, it is easy to mistake dehydration headaches for acute mountain sickness (AMS) headaches (pictured below) and vice versa. If the headache does not improve after drinking one liter of liquid, it should be regarded as an AMS effect.

Dehydration headaches can also be identified by comparing pulse rates: if the pulse rate rises by more than 20% while standing for five minutes after lying down, more fluid is needed.

Acute mountain sickness

Mountain sickness,aka"Highland syndrome, altitude sickness, altitude sickness"(English:Altitude sickness, acute mountain sickness,abbreviation"AMS"), is the most common unhealthy response to altitude: a series of signs that your body is getting sick and has failed to adapt to higher altitudes.

For your own safety,Assuming altitude, all diseases caused by altitude are mountain sickness. The most common reason people shouldn't drop as quickly as possible is bad assumptions. They believe that acute mountain sickness is a sign of weakness, and their health level means that they cannot have AMS, or mistake their symptoms for flu or other diseases. First assume that acute mountain sickness: it occurs in healthy and strong people. If it turns out that you are indeed sick, then descending to a lower height will make your body heal more easily.

Especially if you have recently risen and you haveHeadachewithAny other symptoms, You have acute mountain sickness. Other signs of acute mountain sickness vary from person to person, including fatigue, dizziness, appetite, loss of appetite, nausea, vomiting, confusion, difficulty walking (known as gait ataxia), rattling, and feeling generally very sick. .

Especially the last three signs indicate that your condition is serious, but you should not wait for the onset of these symptoms before confirming that you have acute mountain sickness: they are fairly reliable indicators of the onset of high altitude cerebral edema (HACE) or high altitude pulmonary edema (HAPE). ).

You and your team should pay close attention to the signs of acute mountain sickness. If you have acute mountain sickness, its symptoms will worsen. People who are very sick may feel confused and don't realize how nauseous they are. Loss of appetite is a particularly good sign: anyone who has been walking or climbing for a day at high altitudes should crave a good meal in the evening.

If you have symptoms of acute mountain sickness, please do not go further. Please consider returning.

If you have signs of high altitude cerebral edema or high altitude pulmonary edema, please return immediately. Your life may depend on it.

High altitude cerebral edema

Climbing Mount Everest

High altitude cerebral edema (HACE) is the terminal stage of acute mountain sickness (in contrast, acute mountain sickness can be considered a mild form of high altitude cerebral edema). When you suffer from high altitude cerebral edema, your brain will swell and stop working normally.

The symptoms of high altitude cerebral edema include many signs of mental failure: confusion, fatigue, and strange behavior. But the most reliable is gait ataxia, you can test it by walking along the toes in a straight line on the ground. Healthy people can easily pass this test, and anyone with balance difficulties will show signs of high altitude cerebral edema.

High altitude cerebral edema is very serious, you may only have a few hours to help people with high altitude cerebral edema. The main treatment is to go down the mountain, but people who experience these symptoms need a lot of help. Dexamethasone is a drug that can be used to relieve symptoms, but it is only a temporary bridge that can provide more time for descent.

Medical research in 2008 showed that the main cause of death of climbers on Mount Everest was high altitude cerebral edema.

Alpine Pulmonary Edema

Alpine Pulmonary Edema (HAPE) is a serious altitude sickness. Sometimes this disease will appear together with acute mountain sickness and high altitude cerebral edema, but sometimes it will appear alone. There are many causes of high altitude pulmonary edema. When you suffer from alpine pulmonary edema, your lungs will fill with fluid. Symptoms include extreme fatigue, dyspnea, collapse, dry cough, bloody pink foamy sputum, and gong sounds in the lungs. It is very common at night.

Alpine pulmonary edema is an extremely serious disease. Suffering from alpine pulmonary edema should be regarded as an extremely serious condition and taken seriously. Nifedipine can relieve the symptoms of high altitude pulmonary edema and buy time for the patient to go to treatment, but it cannot completely treat high altitude pulmonary edema. So it is important to move quickly to low altitude areas.

Cheyne Stokes breathing

At altitudes above 3,000 meters (10,000 feet), some people experience periodic breathing during sleep. This type of breathing is called Cheyne-Stokes breathing. This breathing pattern starts with a few shallow breaths, gradually increases to deep sighing breaths, and then rapidly decreases. The breathing may stop completely for a few seconds, and then the shallow breathing will begin again. When breathing stops, people often become restless and may suddenly feel suffocated when they wake up. This can disrupt sleep patterns and tire climbers.

Acetazolamide helps relieve periodic breathing. This type of breathing is not considered abnormal at high altitudes. However, if it first occurs after illness (except for altitude sickness) or injury (especially head injury), it may be a sign of a serious disorder.

Decompression sickness

Decompression sickness(DCS) is a serious disease that forms nitrogen bubbles in your blood and prevents blood supply to certain parts of the body. Symptoms include persistent tingling or joint pain, fatigue, itching, skin rash, confusion, and collapse. Decompression sickness is caused bySuddenAir pressure changes (effectively increasing the altitude) caused by, for example, the aircraft you are flying loses cabin pressure. Even rapid ascent to most altitudes (for example, by plane) usually does not cause decompression sickness. For those who have recently "scuba diving", with exceptions, they should avoid climbing when the diving altitude exceeds the altitude by 12 to 24 hours, depending on the diving activity. For more information, seescuba divingarticle.

Prevention

Keep hydrated

Remember to hydrate-drink at least one liter of water every day. Drinking a lot of water does not prevent AMS, and the same symptoms (headache, nausea, vomiting, etc.) and severe AMS may occur as electrolyte disorders.

Check blood oxygen level

you can usePulse oximeterTo test your blood oxygen level, which can help you find problems before symptoms appear. This instrument is cheap and easy to buy and has good accuracy. Medical staff in high-altitude areas will have an oximeter on their hands, but you can buy one (or two as a spare) and keep it for yourself.

Gradually adapt to altitude

Everest Base Camp

Adapting to the environment is a process of allowing your body to adapt to lower oxygen levels, by slowly rising to higher altitudes, taking some time to adapt at each altitude. The most important factor is to slowly increase your sleeping altitude (the altitude at which you spend the night). If you are on a hiking or mountain climbing holiday, a typical strategy is to spend the day (or part of the day) at a high altitude and then return to sleep at a low altitude. This also applies to people doing winter sports at high altitudes: skiing on the top of the resort and sleeping on the bottom.

The following are recommended methods to maximize sleep height, which can prevent most people from getting mountain sickness:

• Do not exceed 2400 meters on the first night.
• After 3000 meters, increase your sleep height by 300 meters every night.
• Every 1,000 meters, you should spend the second night at the same altitude. If you increase at the maximum speed suggested above, this will be once every four nights.

Of course, you can increase it more slowly than this speed. Many people who have risen from sea level choose to spend a few nights at an altitude of 2500 to 3000 meters before adapting to higher altitudes.

During the adaptation process, drink a lot of non-alcoholic beverages. Some people find that a vegetarian diet can accelerate adaptation to the environment slightly. Local recipes like Peru's mate de coca (tea extracted from coca leaves) are good, but their effectiveness is questionable.

Avoid rapid ascent

rise rapidlyContrary to adapting to the environment: when you get higher than the recommended altitude, you will rise quickly. This may meanthe climbAnd camping is higher than the recommended value, but you can also passdriveGo to the high altitude area for a faster ascent, and start from the low position from the high altitude to the high altitude is a more rapid ascent. For example, flying from sea level toLhasa, Which is 3700 meters high, which is obviously unwise. Consider spending a week or so at medium altitude. Some possibilities seeLand to Tibet. If you are traveling to Tibet, some living areas are more than 5,000 meters, and some mountains are more than 8,000 meters, so don't leave until Lhasa is fully adapted. If you goAndes, The same is true,Cusco，La PazorInca TrailOther destinations are located above 3000 meters above sea level.

When possible, avoid ascents faster than recommended above, especially any sudden ascents to 3000 meters or higher. Even if you take acetazolamide (pictured below), a rapid rise will make you more likely to get mountain sickness and make it progress to a "faster" "serious disease", so you will have less time to respond And drop.

Be especially vigilant with oxygen equipment: some tourists die of altitude when the equipment fails and are completely immune to the weather.

Consider traveling by road or rail instead of flying directly to high altitudes. But keep in mind that the ground options often involve higher altitudes: for example, the Manali-Leh road will take you from below 2000 meters to 5000 meters. orPhased flight, Parked somewhere at a medium height. If you have to fly about 3000 meters to any destination, at least stop at some intermediate destination on the way for a few days. If you fly to a more moderate altitude above 2500 meters, you still need to spend a few nights at that altitude to reach a higher country.

Please avoid "smoking" and "alcohol" when you take an airplane from a high altitude area to a high altitude area.

treatment

Aconcagua Mountaineers Cemetery

Once symptoms of mountain sickness appear, your first task is to recover. Until the symptoms disappear, you cannot raise the height any further. This can take up to 48 hours, if it takes longer, it drops. You can also drop when symptoms appear, which will make them disappear faster, possibly within a few hours.

If you get worse or show signs of high altitude pulmonary edema or high altitude cerebral edema, you must descend to a lower altitude as soon as possible. If it's night, don't wait until morning if you have a choice. You should go down to at least the last night when you have no symptoms of mountain sickness. You may need to seek hospital care.

People with high altitude pulmonary edema and high altitude cerebral edema often feel confused or tired and may need help descending. Help them!

There are some devices that can be used to treat people with high-altitude alpine pulmonary edema or high-altitude cerebral edema, including high-pressure bags, where the patient can lie in a higher-pressure atmosphere. Also, because the main cause of these diseases is hypoxia, breathing oxygen from the tank will slow their onset and may temporarily relieve symptoms. If the treatment is too dangerous to drop, then any treatment will take some time, but they cannot replace blood.

Patients with decompression sickness need to be hospitalized and treated in a recompression chamber: the drop in sea level is not enough to relieve the symptoms of decompression sickness. As with high altitude pulmonary edema and high altitude cerebral edema, breathing oxygen can temporarily relieve symptoms, which can be rescued. The scuba diving organization can provide further advice.

Acetazolamide

This medicine will stimulate your breathing. The drug was originally designed to treat glaucoma, but the side effects of increased breathing rate and depth have proven to be useful for climbers. It has the effect of increasing the adaptation rate, improving periodic breathing, and helping people recover from mountain sickness faster. There are some side effects. This medicine acts as a diuretic and is prone to dehydration, so it is very important to drink plenty of water. This drug is useful for people who have had mountain sickness in the past; people are forced to ascend (for example, flying into Tibet); anyone with mountain sickness, especially if they choose not to descend. Many climbers also take it as a preventive measure.

Acetazolamide is not an absolute preventive measure, especially in the case of forced ascent. A prescription is necessary, and a doctor should be consulted about the appropriate dosage.

Other medicines

Salmeterol (Serevent), temazepam (Temaze), nifedipine and dexamethasone. Some of these drugs are in capsules sold in China, such as Gao Gao Kang which contains dexamethasone. Some herbal preparations are also said to be used to prevent/treat altitude sickness, such as ginkgo and a combination capsule called Gaoyuanning sold in China. The effectiveness of these preparations has not been scientifically proven, although Gaoyuanning (Chinese military personnel) used Gaoyuanning during the rapid ascent.

It is worth noting that all these drugs have obvious side effects, especially dexamethasone, a powerful steroid drug. Visitors are advised to consult a doctor before obtaining these drugs. Foreign tourists should purchase any necessary medicines in their home countries and pay attention to the ingredients contained in the medicines.