Mountain air. Altitude sickness, myths and reality Oxygen deficiency at what altitude

At an altitude of several kilometers, a person begins to feel a lack of oxygen in the blood - he develops altitude or mountain sickness. Experienced climbers warn – this is no joke! Oxygen starvation can lead to irreversible health consequences, so when going to the mountains, do not forget about the first aid kit and safety equipment. Interestingly, this illness can be detected not only by poor health, but also by changes in behavior. But first things first.

What is altitude sickness

Among themselves, climbers call altitude sickness by affectionate nicknames: mountain climber or acclimator. However, a diminutive name in slang does not make the disease less dangerous. Altitude sickness is hypoxia (oxygen starvation of body tissues) when raised to a height of 2.5 thousand meters. This problem is also manifested by a lack of carbon dioxide (hypocapnia) and other changes in human organs. When planning to conquer the next peak, take a professional high-altitude climber and a medical worker into your group. These people can save your life.

At what altitude does oxygen starvation begin?

High blood pressure at an altitude of 3000 meters is the first symptom of altitude sickness, according to statistics, which can occur earlier - from 2000 meters above sea level, here everything depends on individual conditions (the physical form of the climber, chronic diseases, ascent speed, weather conditions and other factors) . The first signs can be felt at an altitude of 1500 meters; above 2500 meters oxygen starvation manifests itself in full force.

Symptoms

Let's look at the symptoms of oxygen starvation when climbing to altitude. Depending on the number of meters traveled, the symptoms of altitude sickness intensify. At first, a person attributes everything to fatigue, however, the higher you go, the more difficult it is to ignore the symptoms of altitude sickness. At an altitude of 1500 meters, the pulse quickens and there is a slight increase in blood pressure. At the same time, the level of oxygen in the blood remains within acceptable limits.

Above 2500 meters, the symptoms begin to quickly “gain momentum”, especially when it comes to high-speed acclimatization. If the ascent to the mountains is carried out in a short time of up to 4 days, then climbers talk about a technically difficult route. At this stage, participants experience problems with the nervous system. A person may experience irritation and increased aggression towards other participants.

If there is a change in behavior, it is recommended to check the cardiovascular system. The pulse will be increased to 180 beats per minute or more. The heart works intensively, trying to supply the body with the necessary amount of oxygen. At this altitude, breathing problems will begin. The number of breaths during acclimatization in one minute will exceed 30 times. The presence of such symptoms indicates a diagnosis of altitude sickness.

Signs

At an altitude of more than 3500 meters, the signs of oxygen starvation will intensify. Problems with sleep will begin: pathologically rare breathing caused by hypocapnia. At the same time, a lack of carbon dioxide will provoke a decrease in the number of breaths during sleep, and this leads to an increase in hypoxia. As a result, short-term suffocation and respiratory arrest may occur during sleep. Neurological disorders will increase, the climber will begin to see hallucinations and be in a state of euphoria.

Symptoms of altitude sickness may worsen with intense physical activity. However, small loads can be useful under hypoxic conditions. They enhance metabolic processes in the body, thereby reducing oxygen starvation. At an altitude of over 5800 meters, the body begins to suffer from a lack of water - dehydration, a deficiency of potassium, magnesium and other trace elements occurs. If we add to this climatic conditions, such as strong winds and sudden changes in temperature, then a long stay here is impossible for unprepared people.

If you climb 8 km into the mountains, it is dangerous to stay here for more than two days without acclimatization. This applies even to experienced trained climbers who have not lost their reserves along the way. The 8,000 meter mark is called the “death zone.” This means that energy consumption exceeds its intake into the body through food, air, and sleep. Without a reserve of strength, a person dies. Death from altitude in medicine was confirmed by the depressurization of the aircraft at an altitude of 10 km: without additional oxygen, passengers died.

Causes of altitude sickness

The cause of altitude sickness is a lack of oxygen and carbon dioxide, which is accompanied by difficult hiking conditions. The climber's breathing becomes faster and deeper. The heart undergoes increased stress during this period: it increases the number of blood cycles over a certain period of time. Result: increased heart rate. The liver, bone marrow and other organs begin releasing red blood cells, which leads to an increase in hemoglobin. Changes also occur in the muscles due to the load on the capillaries.

Lack of oxygen leads to poor brain function. Hence - clouding of consciousness, hallucinations, behavioral disturbances, etc. Hypoxia also affects the gastrointestinal tract. Climbers lose their appetite, suffer from vomiting and abdominal pain. Impaired liver function leads to fever. At a body temperature of 38 degrees, the body requires twice as much oxygen, which is already in short supply. In this case, the expedition member must be urgently evacuated down.

Stages

The development of altitude sickness and the mechanism of manifestation of symptoms are conventionally divided into stages. In many ways, this classification depends on the height of the climb, the physical training of the climber, the time spent at a particular height, the region and even the gender of the climber. For example, a height of 7 km in the Himalayas feels like 5 km on Elbrus. Interestingly, women tolerate hypoxia more easily. Conventionally, altitude climbers divide altitude sickness into the following stages:

• Stage 1. The first symptoms appear. This occurs at a low altitude of 2000-3000 meters. An upset stomach, mood swings, poor sleep, and shortness of breath appear. The climber loses his appetite. If at the end of the day there is a desire to eat all the reserves, it means that acclimatization is occurring. This is a good reaction to height.
• Stage 2. Height – 4-5.5 km. Altitude sickness manifests itself in a throbbing headache, severe nausea, and vomiting. There is forgetfulness, clouding of consciousness, loss of concentration, drowsiness, blurred vision, loss of fluid in the body.
• Stage 3. Height – 5.5-6 km. The headache continues to be tormented, which is not suppressed even by potent analgesics. The vomiting does not stop, but a new symptom is added: cough. The climber loses orientation and coordination of movements.
• Stage 4. Altitude 6 km. Climbing can cause swelling of the brain and lungs. Urgent descent down!

Varieties

Altitude sickness can present with its own symptoms for every climber. Individual characteristics make themselves felt at different heights. This is especially true for altitudes above 5000 meters. Therefore, it is better not to cross this line without an experienced climber and medic. Please note that death from altitude sickness occurs very quickly, so getting caught up in the excitement can be life-threatening.

Treatment of altitude sickness

Inexperienced climbers, when faced with acclimatization at altitude, can develop pulmonary and cerebral edema, which is especially dangerous without proper medical care in mountainous areas. Remember that acute altitude sickness can only be cured by descending, and the following remedies will help relieve symptoms:

• Imodium or its analogues for intestinal disorders;
• Acetazolamide or Diacarb to lower blood pressure;
• analgesics for headaches;
• strong tea that relieves drowsiness.

Treatment of pulmonary edema

What to do if the worst thing happens - pulmonary edema? Urgently hospitalize the patient downstairs, otherwise death cannot be avoided. On the way, every half hour, give him a nitroglycerin tablet under his tongue and give him a Lasix injection. If you have a fever, you can use any drug that reduces the temperature. Give the drink one sip at a time, do not give salty food, keep the patient in an upright position.

Treatment of cerebral edema

You can avoid the consequences of cerebral edema only by starting an immediate, rapid descent. On the way, the patient needs to take two Diacarb tablets, then one tablet twice a day. You will need to give an injection of Dexamethasone (3 ml), injections of which must be repeated every 6 hours. For fever, any suitable remedy, for example, Paracetamol, will do. Do not give a lot to drink, do not put it in a horizontal position.

The name itself "mountain sickness" already suggests that this disease develops in people at high altitudes.

Why is this happening?

As the altitude increases the body stops receiving the required amount of oxygen. This happens not only because there is less oxygen at altitude. It's all about low air pressure and a correspondingly reduced oxygen pressure, which is why the blood flowing through the lungs does not have time to capture a sufficient amount of this gas. At sea level, blood is 95% oxygenated. At an altitude of 8.5 km. saturation drops to 71%.

You don't have to be a professional climber or skier to get altitude sickness. Any person who travels - by plane, car, bicycle, cable car or simply in hiking boots, having climbed to a height 1000m or higher above sea level is at risk of encountering this problem. Moreover, sometimes such travelers, unaccustomed to high altitudes, develop an extremely severe, acute form of mountain sickness - high-altitude pulmonary edema, i.e. a potentially fatal accumulation of fluid in the lungs.

Mountain sickness can affect young and old, men and women, trained and untrained people, beginners and veterans of high-altitude climbing. If you are planning on climbing to the top, you just need to take some precautionary measures to avoid serious health problems that await you in the mountains at an altitude of more than 2.5 km.

Some people adapt quickly to lack of oxygen, but others fail. Altitude sickness can affect anyone. Usually people adapt to an altitude of 3000m within a few days, but acclimatization to higher altitudes can take several weeks.

What are the symptoms of altitude sickness?

If you experience shortness of breath, nausea and headaches when climbing mountains, know that these are the first symptoms of the disease. Drinking plenty of fluids and painkillers will help. More severe complications of mountain sickness may include:

• pulmonary edema- a dangerous condition in which a large amount of fluid accumulates in the lungs;
• cerebral edema, which develops 24-96 hours after rising to high altitude, and symptoms resemble alcohol intoxication;
• retinal hemorrhage, which may be accompanied by the appearance of a small blind spot in the field of view.

By the way, people who constantly live at altitude develop chronic mountain sickness, which very often manifests itself as heart failure. Nitroglycerin is effective in this case. Still, not everyone can live at altitude!

The intensity of development of mountain sickness depending on altitude

Although different people adjust to heights at different rates, the general recommendation is: at an altitude of more than 3 km, the ascent should be made no faster than 500 meters per day. This figure can be reduced to 250-300 meters if the group includes beginners who are in the mountains for the first time, or older people.

Experts say a good way to prevent altitude sickness would be to spend the night at a lower altitude to adapt to some extent. But what if you don't have the time or patience for this? You need to drink more fluids, avoid alcohol and conserve your energy on your first day in the mountains. To prevent altitude sickness, it is recommended to drink 3-4 liters of water per day.

Stop at the first symptoms of illness!

Stay at the same height until any symptoms disappear. Only when they completely pass, consider that you have acclimatized and can continue climbing.

ATTENTION! In all cases of severe mountain sickness, when a person, despite stopping the climb, does not feel better or gets worse and worse, this rule is violated! Immediate descent required!

Basically, if you are unsure of yourself, it is always wise to start descending when symptoms appear. In fact, once you come down, your condition will improve faster.

If anyone in the group begins to look unwell and unsteady, consider that person to be in significant danger and in need of immediate assistance. And it is always important to remember that if one of your companions complains of headaches or other symptoms of altitude sickness, you should stop climbing until they feel better.

Providing assistance with mountain sickness

If, despite the measures taken, any of the participants in the high-altitude trek exhibit symptoms of mountain sickness, it is necessary:

• for headaches take citramon, pyramidon (no more than 1.5 g per day), analgin (no more than 1 g per single dose and 3 g per day) or their combinations (triad, quintuplet);
• for nausea and vomiting- aeron, sour fruits or their juices;
• for insomnia- Noxiron, when a person has difficulty falling asleep, or Nembutal, when sleep is not deep enough.

First of all, this applies to biologically active substances (phenamine, phenatine, pervitin) that stimulate the activity of nerve cells. It should be remembered that these substances create only a short-term effect. Therefore, it is better to use them only when absolutely necessary, and even then during the descent, when the duration of the upcoming movement is not long. Overdose These drugs lead to exhaustion of the nervous system and a sharp decrease in performance. An overdose of these drugs is especially dangerous in conditions of prolonged oxygen deficiency.

If the group has decided to urgently descend a sick participant, then during the descent it is necessary not only to systematically monitor the patient’s condition, but also to regularly give injections of antibiotics and drugs that stimulate human cardiac and respiratory activity (lobelia, cardamine, corazol or norepinephrine).

Tips and instructions

Altitude sickness(miner, acclimukha - slang) - a painful condition of the human body that has risen to a significant altitude above sea level, which occurs as a result of hypoxia (insufficient oxygen supply to tissues), hypocapnia (lack of carbon dioxide in tissues) and is manifested by significant changes in all organs and systems of the human body. body.

If treated incorrectly or taken incorrectly (delay in evacuation down), mountain sickness can even lead to the death of the sick person. Sometimes very quickly.

Since not every sports group has a medical professional, in this article we will try to make the symptoms of mountain sickness “recognizable” and the treatment tactics understandable and reasonable.

So at what altitudes should you expect mountain sickness to develop?

At altitudes of 1500-2500 m above sea level, slight functional changes in well-being are possible in the form of fatigue, increased heart rate, and a slight increase in blood pressure. After 1-2 days (depending on the athlete’s training) these changes, as a rule, disappear. Blood oxygen saturation at this altitude is practically within normal limits.

When climbing quickly to an altitude of 2500-3500 m above sea level, the symptoms of hypoxia develop very quickly and also depend on the training of the athletes. When planning a very short period of time for acclimatization of a group, which is now far from uncommon, if after a training climb on the 3-4th day of ascent, a sports group already enters a technically difficult route, the participants may experience symptoms from the nervous system - inhibition on the route, poor or slow execution of commands, sometimes euphoria develops. A calm and modest athlete suddenly begins to argue, shout, and behave rudely. In this case, it is very important to immediately check the indicators of the cardiovascular system - hypoxia will be manifested by an increase in heart rate (more than 180), an increase in blood pressure (this can be determined by the strength of the pulse wave on the wrists), an increase in shortness of breath (shortness of breath is considered an increase in the number of breaths more than 30 for 1 minute). If these symptoms are present, the diagnosis of mountain sickness can be made for sure.

At an altitude of 3500-5800 meters blood oxygen saturation will be much less than 90% (and 90% is considered normal), so manifestations of mountain sickness are more common, and the development of its complications is also often observed: cerebral edema, pulmonary edema.

During sleep, the patient may experience pathological rare breathing (so-called “periodic” breathing, caused by a decrease in the level of carbon dioxide in the blood), mental disorders, and hallucinations. A decrease in carbon dioxide in the body leads to a decrease in the frequency of inhalations during sleep due to a decrease in the activity of the respiratory center of the brain (when a person is awake, the number of inhalations is regulated by consciousness), which further increases hypoxia. This usually manifests itself in the form of attacks of suffocation or even temporary cessation of breathing during sleep.

During intense physical activity, symptoms of altitude sickness may worsen. However, a little physical activity is useful, as it stimulates anaerobic metabolic processes in the body and neutralizes the increase in hypoxia in organs and tissues. The need to move in order to overcome it was mentioned by many high-altitude athletes (Reinhold Messner, Vladimir Shataev, Eduard Myslovsky).

Extreme heights include the level above 5800 m above sea level, prolonged stay at such an altitude is dangerous for humans. High levels of ultraviolet radiation, strong, sometimes hurricane-force winds, and temperature changes quickly lead to dehydration and exhaustion of the body. Therefore, those who climb to such a height must be very hardy and trained to the effects of hypoxia, and must consume a sufficient amount of water and high-calorie, quickly digestible foods during the ascent.

At altitudes above 6000 m complete acclimatization is even more difficult, in connection with this, even many trained high-altitude climbers noted numerous signs of mountain sickness during their stay at high altitudes (fatigue, sleep disturbances, slow reaction, headache, impaired taste, etc.).

At altitudes above 8000 m a non-acclimatized person can be without oxygen for no more than 1-2 days (and then only in the presence of general high fitness and internal reserves). The term “Death Zone” (lethal zone) is known - a high-altitude zone in which the body, to ensure its own vital functions, spends more energy than it can receive from external sources (nutrition, breathing, etc.). An extreme confirmation of the lethality of altitude is information from aviation medicine - at altitudes of about 10,000 m, a sudden depressurization of the aircraft cabin leads to death if oxygen is not immediately connected.

How does mountain sickness develop?

Most processes in our body occur with the help of oxygen, which, when inhaled, enters the lungs, then, as a result of gas exchange in the lungs, penetrates the blood, and, passing through the heart, is sent to all organs and systems of the human body - to the brain, kidneys, liver, stomach, as well as muscles and ligaments.

As altitude increases, the amount of oxygen in the surrounding air decreases and its amount in the human blood decreases. This condition is called hypoxia. In the case of slight hypoxia, the body responds to a decrease in oxygen levels in tissues, first of all, by increasing heart rate (increasing pulse), increasing blood pressure, and releasing more young red blood cells from the hematopoietic organs - depot (liver, spleen, bone marrow), which capture additional oxygen, normalizing gas exchange in the lungs.

In the mountains, especially high ones, other factors are added to the decrease in oxygen content in the air: physical fatigue, hypothermia, and dehydration at altitude. And in case of accidents, there are also injuries. And if in such a situation you do not influence the body correctly, physiological processes will take place in a “vicious circle”, complications will arise, and the life of the climber may be in danger. At altitude, the speed of pathological processes is very high; for example, the development of pulmonary or cerebral edema can cause the death of the victim within a few hours.

The main difficulty in diagnosing mountain sickness is due, first of all, to the fact that most of its symptoms, with a few exceptions (for example, periodic intermittent breathing), are also found in other diseases: cough, difficulty breathing and shortness of breath - in acute pneumonia, abdominal pain and digestive disorders - in case of poisoning, disturbances of consciousness and orientation - in case of traumatic brain injury. But in the case of mountain sickness, all of these symptoms are observed in the victim either during a rapid rise to altitude, or during prolonged stay at altitude (for example, when waiting out bad weather).

Many conquerors of eight-thousanders noted drowsiness, lethargy, poor sleep with symptoms of suffocation, and their health immediately improved with a rapid loss of altitude.
Common colds, dehydration, insomnia, overwork, and drinking alcohol or coffee also contribute to the development of altitude sickness and worsen well-being at altitude.

And simply the tolerance to high altitudes is very individual: some athletes begin to feel a deterioration in their condition at 3000-4000 m, others feel great at a much higher altitude.

That is, the development of mountain sickness depends on individual resistance to hypoxia, in particular on:

• gender (women tolerate hypoxia better),
• age (the younger the person, the worse he tolerates hypoxia),
• general physical fitness and mental state,
• speed of rise to altitude,
• as well as from past “high-altitude” experience.

The geography of location also influences (for example, 7000 m in the Himalayas is easier to endure than 5000 m on Elbrus).

So how does an athlete’s body react to a significant decrease in oxygen content in the surrounding air?

Pulmonary ventilation increases - breathing becomes more intense and deeper. The work of the heart increases - the minute volume of circulating blood increases, blood flow accelerates. Additional red blood cells are released from blood depots (liver, spleen, bone marrow), resulting in an increase in hemoglobin content in the blood. At the tissue level, capillaries begin to work more intensively, the amount of myoglobin in the muscles increases, metabolic processes intensify, and new metabolic mechanisms are activated, for example, anaerobic oxidation. If hypoxia continues to increase, pathological disorders begin in the body: insufficient oxygen supply to the brain and lungs leads to the development of severe complications. A decrease in oxygen levels in brain tissue first leads to disturbances in behavior and consciousness, and subsequently contributes to the development of cerebral edema. Insufficient gas exchange in the lungs leads to reflex stagnation of blood in the pulmonary circulation and the development of pulmonary edema.

A decrease in blood flow in the kidneys leads to a decrease in the excretory function of the kidneys - first a decrease, and then a complete absence of urine. This is a very alarming sign, because a decrease in excretory function leads to rapid poisoning of the body. A decrease in oxygen in the blood of the gastrointestinal tract can manifest itself as a complete lack of appetite, abdominal pain, nausea, and vomiting. In addition, when the level of oxygen in tissues decreases as a result of impaired water-salt metabolism, dehydration of the body progresses (fluid loss can reach 7-10 liters per day), arrhythmia begins, and heart failure develops. As a result of liver dysfunction, intoxication quickly develops, body temperature rises, and fever in conditions of lack of oxygen increases hypoxia (it has been established that at a temperature of 38°C the body's need for oxygen doubles, and at 39.5°C it increases 4 times).

Attention! If the temperature is high, the patient must be brought down immediately! A “miner” can add a catastrophic “minus” to any pathology!

Worsening the state of health and the effects of cold:

• Firstly, in the cold, inhalation is usually short, and this also increases hypoxia.
• Secondly, at low temperatures, other colds (sore throat, pneumonia) may be associated with pulmonary edema.
• Thirdly, in the cold, the permeability of cell walls is impaired, which leads to additional tissue swelling.

Therefore, at low temperatures, pulmonary edema or cerebral edema occurs and develops faster: at high altitudes and in extreme cold, this period, even death, can be only a few hours instead of the usual 8-12 hours.

The rapid onset of death is explained by the fact that processes develop according to the principle of a “vicious” circle, when subsequent changes aggravate the cause of the process, and vice versa.

As a rule, all complications in the development of mountain sickness develop at night, during sleep, and by morning there is a significant deterioration in the condition. This is due to the horizontal position of the body, decreased respiratory activity, and increased tone of the parasympathetic nervous system. Therefore, if possible, it is extremely important not to put a person suffering from altitude sickness to sleep at altitude, but use every minute to transport the victim down.

The cause of death with cerebral edema is compression of the brain matter by the cranial vault, wedging of the cerebellum into the posterior cranial fossa. Therefore, it is very important to use both diuretics (reducing brain swelling) and sedatives (sleeping pills) at the slightest symptoms of brain damage, because the latter reduce the brain’s need for oxygen.

In pulmonary edema, the cause of death is respiratory failure, as well as obstruction of the airways (asphyxia) by foam formed during swelling of the lung tissue. In addition to this, pulmonary edema during mountain sickness is usually accompanied by heart failure due to overflow of the pulmonary circulation. Therefore, along with diuretics that reduce swelling, it is necessary to give cardiac drugs that increase cardiac output and corticosteroids that stimulate the heart and increase blood pressure levels.

In the functioning of the digestive system, when dehydrated, the secretion of gastric juice decreases, which leads to loss of appetite and disruption of the digestive processes. As a result, the athlete sharply loses weight and complains of discomfort in the abdomen, nausea, and diarrhea. It should be noted that digestive disorders during mountain sickness differ from diseases of the digestive tract, primarily in that the other participants in the group do not observe signs of poisoning (nausea, vomiting). Diseases of the abdominal organs such as perforation of an ulcer or acute appendicitis are always confirmed by the presence of symptoms of peritoneal irritation (pain appears when pressing on the abdomen with a hand or palm, and sharply intensifies when the hand is withdrawn).

In addition, as a result of impaired brain function, a decrease in visual acuity, a decrease in pain sensitivity, and mental disorders are possible.

Symptoms

According to the time of exposure to hypoxia on the body, there are acute And chronic forms of mountain sickness.

Chronic mountain sickness observed in residents of high mountain areas (for example, the village of Kurush in Dagestan, 4000 m), but this is already the sphere of activity of local doctors.
Acute mountain sickness occurs, as a rule, within a few hours, its symptoms develop very quickly.
In addition, they distinguish subacute form of mountain sickness, which lasts up to 10 days. Clinical manifestations of acute and subacute forms of mountain sickness often coincide and differ only in the time of development of complications.

Distinguish light, average And heavy degree of mountain sickness.
For mild mountain sickness characterized by the appearance of lethargy, malaise, rapid heartbeat, shortness of breath and dizziness in the first 6-10 hours after rising to altitude. It is also characteristic that drowsiness and poor sleep are observed simultaneously. If the rise to altitude does not continue, these symptoms disappear after a couple of days as a result of the body’s adaptation to the altitude (acclimatization). There are no objective signs of a mild form of mountain sickness. If these symptoms appear within 3 days after rising to altitude, the presence of some other disease should be assumed.

At moderate mountain sickness characterized by inadequacy and a state of euphoria, which are subsequently replaced by loss of strength and apathy. Symptoms of hypoxia are already more pronounced: severe headache, dizziness. Sleep is disturbed: patients have trouble falling asleep and often wake up from suffocation, they are often tormented by nightmares. With exertion, the pulse increases sharply and shortness of breath appears. As a rule, appetite completely disappears, nausea appears, and sometimes vomiting. In the mental sphere, there is inhibition on the route, poor or slow execution of commands, and sometimes euphoria develops.
With a rapid loss of altitude, your health immediately improves before your eyes.

At severe mountain sickness symptoms of hypoxia already affect all organs and systems of the body. The result is poor physical well-being, rapid fatigue, heaviness throughout the body, which prevents the athlete from moving forward.
The headache increases, and with a sudden change in body position, dizziness and lightheadedness occur. Due to severe dehydration of the body, severe thirst worries, there is no appetite, and gastrointestinal disorders appear in the form of diarrhea. Possible bloating and pain.
During night sleep, breathing is disturbed (intermittent breathing), hemoptysis may occur (hemoptysis differs from bleeding in the presence of foamy sputum; gastric bleeding, as a rule, is never associated with a cough, and the blood coming from the stomach has the appearance of “coffee grounds” due to for interactions with hydrochloric acid of gastric juice).
When examining the patient: the tongue is coated, dry, lips are bluish, the skin of the face has a grayish tint.
In the absence of treatment and descent, mountain sickness leads to serious complications - pulmonary and cerebral edema.
With pulmonary edema in the chest, mainly behind the sternum, moist rales, gurgling, and bubbling appear. In severe cases, coughing may produce pink, frothy sputum from the mouth. The pressure drops, the pulse increases sharply. If treatment is not started immediately, the patient can die very quickly. Be sure to give the sick person a semi-sitting position to relieve the heart and breathing, give oxygen, and administer intramuscular diuretics (diacarb, furosemide) and corticosteroids (dexomethasone, dexon, hydrocortisone). To facilitate the work of the heart, you can apply tourniquets to the upper third of the shoulders and hips for 15-20 minutes. If the treatment is carried out correctly, the condition should improve quickly, after which an immediate descent should begin. If treatment is not carried out, as a result of heart overload, heart failure quickly joins pulmonary edema: the skin turns blue, severe pain appears in the heart area, a sharp drop in blood pressure, and arrhythmia.

High altitude cerebral edema differs from traumatic brain injury, first of all, by the absence of asymmetry of the face, pupils and facial muscles and is manifested by lethargy and confusion, up to its complete loss. At the very beginning of development, cerebral edema may manifest itself as inappropriate behavior (anger or euphoria), as well as poor coordination of movements. Subsequently, the symptoms of brain damage may increase: the patient does not understand the simplest commands, cannot move, or fix his gaze. As a result of cerebral edema, difficulty breathing and cardiac activity may occur, but this occurs some time after loss of consciousness. Brain edema is relieved by fractional (repeated) administration of diuretics (diacarb, furosemide), mandatory administration of sedatives or hypnotics that reduce the brain's need for oxygen, and mandatory cooling of the victim's head (lowering the temperature by several degrees reduces cerebral edema and prevents the development of complications!) .

Prevention of altitude sickness

Climbers and mountain tourists planning climbs and hikes in the mountains should understand that the likelihood of mountain sickness in participants is reduced by:

• good informational and psychological preparation,
• good physical fitness,
• quality equipment,
• correct acclimatization and well-thought-out climbing tactics.

This is especially important for high altitudes (over 5000 m)!

- Good informational and psychological preparation
Be boring in the best sense of the word. Find out thoroughly why mountains are dangerous, why heights are dangerous. Nowadays there is no problem finding any information on the Internet. And if you need an individual consultation with a specialist, then AlpIndustry employees are at your service.

- Good general physical preparation (GPP)
Prevention of mountain sickness consists, first of all, in the advance creation of a good sports form of the athlete during the preparation phase for events in the mountains. With good general physical fitness, the athlete is less tired, better able to withstand the effects of cold, all his organs are prepared for high loads, including in the presence of oxygen deficiency. In particular, for athletes planning to climb high altitudes, it is necessary to include anaerobic training in the training cycle (running uphill, running with breath holding).

Victor Yanchenko, guide and head of our office in the Elbrus region, on the top of Elbrus.
One of the most experienced guides on Elbrus. More than 200 ascents to Elbrus.

- High-quality equipment
“The right” clothes, purchased in stores focused on mountain sports (“AlpIndustry”), bivouac equipment, equipment to ensure movement in the mountains - all these are factors that will save you from the cold (or heat, which can sometimes “ reach" in the sun with no wind), will allow you to move quickly and economically, will provide a reliable and protected bivouac and hot food. And these are factors to counteract altitude sickness.
The “equipment” section should also include planning for the correct selection of products: light, easily digestible, high in calories, with good taste. By the way, when choosing products, it is advisable to take into account the taste preferences of each group member.
When climbing at high altitudes, it is necessary to take multivitamins (preferably with a complex of microelements), antioxidants: tinctures of ginseng, golden root, Rhodiola rosea, ascorbic acid, riboxin (it is advisable to carry out additional fortification of the body in advance, 1-2 weeks before leaving for the mountains ). Taking drugs that affect the pulse rate (potassium orotate, asparkam) in the mountains is not advisable due to the occurrence of various forms of cardiac arrhythmias. Be sure to take products to normalize the water-salt balance (rehydron) in your first aid kit or drink slightly salted water.
Well, you shouldn’t forget about other medications in the first aid kit, just as you shouldn’t forget to consult with your doctor about its composition.

- Correct acclimatization and well-thought-out climbing tactics
Directly in the mountains, it is important to have good and properly carried out acclimatization, moderate alternation of ascents to heights and descents to the overnight location with constant monitoring of the well-being of group members. In this case, you should gradually increase both the height of the base camp and the height of the “peak” ascent points.
You can encounter a situation where an “athlete”, tired of the office, finally escapes into nature - to the mountains, in this case - and decides to relax and “to sleep better” take a dose of alcohol.
So here it is:
The tragic consequences of such “relaxation” in history, even not so long ago, are known: this does not contribute to acclimatization at all, but on the contrary.

Alcohol, even in small doses, is strictly contraindicated in conditions of hypoxia, as it depresses respiration, impairs interstitial fluid exchange, increases the load on the heart and increases oxygen starvation of brain cells.

If the disease does occur...

If, when climbing to a height, one of the group members feels unwell, then in the case of mild to moderate illness, it can be overcome by a smoother acclimatization, without forcing it. That is, go down - come to your senses - go up higher, look at how you are feeling, maybe even spend the night - go down. And so on.

But the main thing is not to miss the symptoms of another disease (see above).

If the disease is severe, the victim must be immediately taken down, as the condition can worsen greatly in a matter of hours, and the descent can become dangerous not only for the victim, but also for other members of the group. Maybe even at night...

Treatment of acute mountain sickness, therefore, begins with the immediate descent of the sick participant to a lower altitude. The best remedy for increasing hypoxia is to increase the oxygen content in the air along with medications.

The following are required when transporting a patient with mountain sickness:

• drinking plenty of water,
• administration of diuretics,
• in case of a sharp drop in pressure or deterioration in general condition, intramuscular injection of corticosteroids.

(Adrenal cortex hormones - corticosteroids - have an adrenaline-like effect: they increase blood pressure, increase cardiac output, and increase the body’s resistance to disease).

Taking 1-2 aspirin tablets can have some effect during hypoxia - by reducing blood clotting, it promotes better oxygen delivery to the tissues, but aspirin can be taken only in the absence of bleeding or hemoptysis.

Alcohol under conditions of hypoxia is strictly contraindicated - we have already talked about this, but in case of illness - we emphasize: CATEGORICALLY!

Thus, the following will help save the life of a person suffering from mountain sickness:

• firstly, correct and quick diagnosis of the symptoms of the disease,
• secondly, the use of modern medications to reduce hypoxia and prevent the development of severe complications,
• thirdly, the immediate descent of the sick participant in the ascent to a safe height for health.

Attention! The group leader is obliged be well aware of the use of medications in the group first aid kit and their contraindications! Consultation with a doctor is required when purchasing!

Attention! Group members must have an appropriate level of health (approved by a doctor) and notify the manager in case of chronic diseases and allergies!

Attention! We must not forget about one more important point. It may turn out that the strength and skills of your comrades will not be enough to evacuate you safely and quickly. And so that your loved ones and friends do not have to raise funds for a helicopter or the work of professional rescuers, DON'T FORGET ABOUT THE CORRECT INSURANCE POLICY!

Remember that when preparing for the climb, you need to pay special attention to the person you are going up the mountain with.

This could be a private guide, working illegally or semi-legally, who will offer a “sweet” price for his services. And in this case, if something goes wrong on the climb, then who will be responsible for your life, safety and resolution of conflict situations?

Prices for active tours from officially operating tour operators are not much higher than from clubs and private guides. And by choosing a company that operates legally on the market, you get a number of advantages:

• Routes and programs carefully designed by professional guides.
• The guarantor of fulfillment of obligations to you is not an individual, but a company that values ​​​​its reputation and has financial and legal responsibility to its clients.
• Official payments; a complete package of documents and instructions allowing you to cooperate on equal terms and in legal security.
• Guides and experts undergo strict selection for professional training and ability to work with clients. By the way, AlpIndustry, together with the FAR (Russian Mountaineering Federation), is the organizer of the international school of mountain guides in Russia. Education at the School is conducted according to the International Standard IFMGA/UIAGM/IVBV. Our country is supervised by the Association of Canadian Mountain Guides (ACMG). And school graduates work in the AlpIndustry Adventure Team.

In any case, the choice is yours.
Have a good and safe climb!

Adventure Team "AlpIndustry" on Mera Peak

Description:

Altitude sickness (high-altitude hypoxia) is a painful condition associated with oxygen starvation due to a decrease in the partial pressure of oxygen in the inhaled air, which occurs high in the mountains, as well as when flying on aircraft that are not equipped with a pressurized cabin (for example, paragliders, hang gliders, hot air balloons ), starting from about 2000 meters and higher above ocean level.

A type of altitude sickness is the occurrence of which, along with a lack of oxygen, also plays a role in such additional factors as physical fatigue, cooling, dehydration, ultraviolet radiation, severe weather conditions (for example, hurricane winds), sudden temperature changes during the day (from + 30 C during the day to −20 C at night), etc. But the main pathological factor of mountain sickness is hypoxia.

A person is able to adapt to high-altitude hypoxia; athletes use these types of adaptation in order to improve their athletic performance. The limit of possible adaptation is considered to be heights of 8000 meters, after which death occurs.

Causes of altitude sickness:

The altitude at which mountain sickness develops varies due to the influence of numerous factors, both individual and climatic.

The following individual factors influence the development of mountain sickness:
individual resistance of people to lack of oxygen (for example, among mountain residents);
gender (women tolerate hypoxia better);
age (young people do not tolerate hypoxia well);
physical, mental and moral state;
level of training;
speed of climb;
degree and duration of oxygen;
intensity of muscle effort;
past “high-altitude” experience.

The following factors provoke the development of mountain sickness and reduce tolerance to high altitudes:
presence of alcohol or caffeine in the blood;
insomnia, overwork;
psycho-emotional stress;
hypothermia;
poor quality and irrational nutrition;
violation of the water-salt regime, dehydration;
excess body weight;
respiratory and other chronic diseases (for example, tonsillitis, chronic purulent dental diseases);
blood loss.

The following climatic factors contribute to the development and faster progression of mountain sickness
Low temperatures - with increasing altitude, the average annual air temperature gradually decreases by 0.5 C for every 100 m (0.4 C in winter, 0.6 C in summer). In winter, at equal altitudes, the incidence is more frequent than in summer. Sudden temperature changes also have an adverse effect.
Humidity - At high altitudes, due to low temperatures, the partial pressure of water vapor is low. At an altitude of 2000 m and above, air humidity is two or more times less than at sea level in the same area.

At high mountain altitudes, the air becomes almost dry (the partial pressure of saturated water vapor is negligible). On the one hand, this leads to increased loss of fluid from the body through the skin and lungs and, consequently, to dehydration. On the other hand, more humid air in a maritime climate has a significantly higher thermal conductivity (thermal conductivity is almost linearly related to the molecular weight of molecules, for water, 18 g/mol, for air - a mixture of gases, 29 g/mol), therefore, contributes to the harmful effects of low temperatures. temperatures; as well as water vapor displaces oxygen from the alveoli of the lungs, lowering its already low content.
Wind - high in the mountains, the wind can reach hurricane force (over 200 km/h), which overcools the body, exhausts us physically and mentally, and makes breathing difficult.

Symptoms of altitude sickness:

The acute form of mountain sickness occurs when non-acclimatized people move quickly (within several hours) to high altitudes, usually to an altitude of more than 3500 m. Its clinical symptoms develop rapidly. In the subacute form of mountain sickness, they do not develop as quickly and last longer (up to 10 days). The clinical manifestations of both forms of mountain sickness are generally the same.

Acute mountain sickness.

Easy degree.

Symptoms of mild mountain sickness appear within 6-12 hours (and sometimes earlier) after ascending to a new altitude. At higher altitudes, its symptoms are detected earlier. For many, they initially manifest themselves in a deterioration in well-being and some lethargy. At first, a beginner feels unwell in the mountains, a rapid heartbeat, lightheadedness, slight shortness of breath during physical exertion, drowsiness, and at the same time has trouble falling asleep. After 3-4 days, these phenomena, if you do not rise higher, usually disappear. There are no clear objective clinical and neurological symptoms of this form of mountain sickness.

All of the above symptoms are not specific and can be the result of many other diseases. Nevertheless, it is considered correct to assume acute mountain sickness if a non-acclimatized person who has risen to an altitude of more than 2500 m begins to have a headache and at least one of the above symptoms appears. If the above symptoms appear after 36 hours of good condition, then the presence of another disease must be excluded.

Average degree.

At altitudes of 2500-3500 m, some people may experience signs of: high spirits, excessive gesticulation and talkativeness, accelerated speech rate, causeless fun and laughter, carefree, frivolous attitude towards the environment. Subsequently, the euphoric state is replaced by a decline in mood, apathy, melancholicity, and interest in the environment becomes dull.

At altitudes of 4000-5000 m, your health worsens. Moderate and even strong development develops. Sleep becomes restless, anxious, with unpleasant dreams; some people have difficulty falling asleep and often wake up from a feeling of suffocation (periodic breathing). With physical effort, breathing and heart rate immediately increase, and dizziness appears. Appetite decreases and vomiting occurs, which can be intense and can lead to vomiting. The taste changes: you want mainly sour, spicy or salty foods (which is partly explained by dehydration and a violation of the water-salt balance). Dry throat causes thirst. Possible from the nose.

Severe degree.

At altitudes of 5000-7000 m and above, health is rarely good, more often it is unsatisfactory. There is a general feeling of weakness, fatigue, and heaviness throughout the body. Moderate and sometimes severe pain in the temples, frontal, and occipital parts of the head does not stop. Dizziness occurs with sudden movements and bends or after work. A person falls asleep with great difficulty, often wakes up, and some suffer from insomnia. A person suffering from altitude sickness is unable to perform physical activity for a long time due to (“breathing of a cornered dog”) and heartbeat, performance decreases, for example, at an altitude of 8000 m, 15-16% of performance capacity remains from that produced at sea level.

The dryness in my throat is increasing, I feel thirsty all the time. The tongue is coated. Many people are concerned about dryness. Appetite is usually reduced or absent. The number of cases of nausea also increases when eating. Pain in the abdomen and gastrointestinal disorders, bloating are often observed. The breathing rhythm during night sleep is disrupted (Cheyne-Stokes breathing). The skin of the face, especially the lips, acquires a pale, often bluish, tint as a result of insufficient oxygen saturation of arterial blood, which loses its scarlet color. The temperature rises by 1-2 C, and... Cases of bleeding from the nose, mouth, lungs (hemoptysis), and sometimes stomach bleeding are becoming more frequent.

Under certain conditions, starting from 4000 m, dangerous forms of mountain sickness may occur, caused by a breakdown of adaptation mechanisms and the development of more serious pathologies: pulmonary edema and cerebral edema.

High altitude pulmonary edema.

Symptoms of high-altitude pulmonary edema usually appear within 2-3 days of staying at high altitude. Liquid emerges from the capillaries of the lungs, which, entering the lumen of the alveoli, interferes with gas exchange, as a result, hypoxia intensifies and the disease progresses. If left untreated, it can take a matter of hours from the first onset of symptoms to death from suffocation. Its development is facilitated by previous diseases of the respiratory and circulatory system, chronic or acute respiratory tract infection (for example, tonsillitis, bronchitis, pneumonia, chronic purulent dental diseases), excessive physical activity performed before stable adaptation has occurred.

High-altitude pulmonary edema is the most common cause of death among all mountain-specific diseases. At 2700 m the incidence of high altitude pulmonary edema is 0.0001% and increases to 2% at 4000 m.

There are 3 stages in the development of high-altitude pulmonary edema:

First stage.

Occurs against the background of symptoms of severe acute mountain sickness:


symptoms of depression of the respiratory center are observed - rapid pulse and breathing, difficulty coughing, the wings of the nose first participate in breathing, teeth are clenched;
chills, fever;
skin is moist, pale;

The following specific symptoms are also characteristic of pulmonary edema:
dry cough, sore throat;
complaints of compression below the sternum, chest pain;
symptom of “vanka-stand up”: due to weakness, the patient tries to lie down, but due to suffocation he is forced to sit down;
Temperature 38-39 °C. If pulmonary edema develops without pneumonia, the temperature can be 36-37 °C.

Second stage.

Usually, 8-12 hours after the first symptoms, the second stage of pulmonary edema occurs:
the patient can no longer stand;
cough with foamy sputum;
the pulse is rapid, blood pressure constantly rises;
breathing is noisy, wheezing is heard when listening;
symptom of “vanka-stand up” or semi-sitting position;
thirst.

Third stage.

Develops after another 6-8 hours and 4-8 hours before death:
signs of significant dehydration: increased thirst;
severe headache;
temperature increase;
motor restlessness;
wheezing heard at a distance;
bloody sputum, pink foam from the nose and mouth;
suffocation; , pressure can reach 150-170/90-100.

Without proper treatment, a drop in pressure, coma, occurs.

High altitude cerebral edema.

High-altitude cerebral edema can be considered an extreme manifestation of acute mountain sickness. Fluid comes out of the capillaries of the brain, and it increases in volume. In this case, the cerebellar tissue is wedged into the spinal cord trunk, the vital centers located in it are destroyed, and death occurs.

There are 3 stages of cerebral edema:

First stage.

Occurs against the background of symptoms of severe acute mountain sickness:
the patient stands on his feet, but does not move independently;
absence of urine for more than 8-10 hours;
symptoms of depression of the respiratory center are observed - rapid pulse and breathing, difficulty coughing, the wings of the nose first participate in breathing, teeth are clenched;
chills, fever;
skin is moist, pale;
cyanosis: blue nails, lips, nose, ears.

Due to changes in the brain, specific symptoms appear:
the head is filled with lead, noise in the head, headaches of a bursting nature;
increased vomiting;
impaired coordination (ataxia): the gait, as well as the patient’s behavior in general, most closely resembles a state of alcohol intoxication; the person cannot walk in a straight line without staggering;
lethargy, drowsiness, detachment, apathy;
the patient fulfills requests under control and immediately stops fulfilling them until a second reminder;
Unlike pulmonary edema, the patient can lie down.

Second stage.

Usually, 8-12 hours after the onset of the first symptoms, the second stage of cerebral edema occurs:
increased headaches, insomnia, thirst;
speech disorders;
changes in behavior: a person ceases to be like himself, irrational behavior (aggression, attempted suicide). Moreover, the patient may not understand what is happening to him, and actively resist attempts to lower himself, being in a state of euphoria, rush upward;
stupor, lethargy, detachment, apathy;
changes in the pupils: dilation, disappearance of light reaction, gaze fixation, asymmetry.

Third stage.

After another 6-8 and 4-8 hours before death, the third stage begins:
signs of significant dehydration: thirst;
headache gets worse;
temperature increase;
motor restlessness;
increased changes in the pupils, dilation of the fundus veins;
numbness of the limbs;
depression of consciousness, stupor, lethargy, the victim becomes lethargic, drowsy, answers questions in monosyllables and not immediately, and may be disoriented in the surrounding environment.

At the end of the third stage, loss of consciousness, cessation of breathing and cardiac activity occurs.

Treatment for altitude sickness:

For treatment the following is prescribed:

Light and medium degree.

It must be emphasized that a mild degree of mountain sickness, despite the unpleasant sensations, is usually only a condition that physically limits a person without any lasting consequences. Basics of treating mild symptoms of mountain sickness:
Rest;
Liquids (juices, teas);
Weak analgesics (aspirin, ibuprofen, paracetamol);
medications for nausea (aeron, sour fruits - apples, oranges, lemons, apricots) and vomiting (intramuscular administration of metoclopramide (Raglan));
If necessary, prescribe acetazolamide 125-250 mg twice daily for 3 days.

Under favorable circumstances, symptoms usually disappear after 2-4 days.

Severe degree.
The most effective method of treatment is to lower the victim down. Every opportunity for independent movement of the victim should be fully used, which does not allow apathy, indifference and hypothermia to develop.
In extreme cases, an oxygen mask should be used (preferably mixed with carbon dioxide: O2 + 5-7% CO2). It is effective to use a portable hyperbaric pressure chamber (compression chamber), which is a sealed bag into which air is pumped by a hand pump or compressor.
Acetazolamide 125-250 mg twice daily for 3 days.
Dexamethasone 8 mg orally, then 4 mg every 6 hours during the day.
The temperature should be reduced to 37 °C with antipyretic drugs.
Narcotic analgesics (promedol, morphine) and alcohol should not be used.

Treatment of pulmonary edema.
The most important method of combating pulmonary edema is immediate descent. Descending even a few hundred meters can lead to improvement.
The use of a portable hyperbaric chamber is effective. In extreme cases, an oxygen mask should be used.
The victim must be placed in a semi-sitting position.
If systolic blood pressure (“upper”) is more than 90 mm Hg. Art., then 2-3 ampoules of furosemide must be administered intramuscularly.
Nifedipine is effective for the prevention and treatment of high-altitude pulmonary edema (initially 10 mg orally, then 20 mg of slow-release nifedipine every 12 hours).
Place a nitroglycerin tablet under the tongue (if systolic blood pressure is more than 90 mm Hg). Nitroglycerin can be given again after 20 minutes no more than 3 times.
Place venous tourniquets on the thighs so that the pulse in the arteries can be felt below the place where they are applied. This will create a blood depot in the lower extremities and prevent it from returning to the heart. True, this method should be used only during the rapid descent of the victim down, in order to gain some time. After all, after an hour and a half, the tourniquets will have to be removed, and a sharp flow of blood to the heart driven by hypoxia can cause acute heart failure.
If possible, aminophylline should be administered intravenously (10 ml. 2.4% in 100 ml. isotonic solution).
If the patient clearly produces pink, foamy sputum, breathe through gauze moistened with alcohol to reduce foaming in the pulmonary alveoli.

Under stationary conditions, when maintaining consciousness does not play a role, morphine should be used; it reduces the pressure in the pulmonary artery.

Important: you need to know that no medicinal manipulations should serve as a delay for going down.

Pulmonary edema can very quickly develop against the background of inflammatory diseases of the respiratory tract (tonsillitis, pneumonia), therefore, when signs of these appear, a person must be taken down, while simultaneously providing symptomatic medical assistance.

Treatment of cerebral edema.
If symptoms of high-altitude cerebral edema appear, you should immediately begin descent. A delay can lead to the death of the patient. If symptoms appear in the evening, you cannot wait until the morning to come down. It is necessary to evacuate at least to the altitude at which the person last felt well, and preferably up to 2500 m. As a rule, if you start descending in time, the symptoms quickly and completely disappear.
We need to start supplying oxygen.

Medicines for cerebral edema play a rather auxiliary role, but, nevertheless, they should not be neglected. To reduce symptoms and facilitate evacuation, dexamethasone is used (initially 8 mg, then 4 mg every 6 hours orally or parenterally).

In case of cerebral edema, both vasodilators (nitroglycerin, nifedipine, trental) and blood pressure-increasing drugs (caffeine, adrenaline) should not be used: any increase in pressure or vasodilation will increase cerebral edema. The use of diuretics is now also not recommended.

The disappearance of symptoms does not occur immediately after descent, and the patient should be transferred under the supervision of medical workers.

Until recently, it was believed that heavier gases predominate in the atmosphere adjacent to the earth's surface, and lighter gases far from it.

Numerous studies conducted in recent years have not confirmed this assumption. It was also not confirmed by analysis of air samples taken at an altitude of 70 kilometers using special rockets.

The results of the analysis of these samples and other studies have shown that the composition of air in layers of the atmosphere remote from the earth remains almost unchanged and the percentage of oxygen in it is the same as at the surface of the earth.

Since the barometric pressure of the air decreases as it moves away from the ground, the pressure of each component of the air separately decreases, that is, the partial pressure of oxygen, nitrogen and other gases that make up the air decreases.

The partial pressure of oxygen at an altitude of 10 kilometers is almost 4 times less than at the surface of the earth, and is only 45 millimeters of mercury instead of 150 at sea level.

The rate of oxygen penetration into blood vessels by diffusion is determined not by its percentage in the air, but by partial pressure. That is why, despite the fact that the oxygen content in the air at high altitudes is 21 percent, the amount of oxygen becomes less and less as we move away from the ground and people find it difficult to breathe. At an altitude of about 5 thousand meters, where the partial pressure of oxygen drops to 105 millimeters of mercury, a person already experiences heaviness in the head, drowsiness, nausea, and sometimes loss of consciousness. This condition is characteristic of oxygen starvation, which is caused by a low oxygen content in the air compared to its normal content at sea level.

A decrease in the partial pressure of oxygen to 50-70 millimeters of mercury causes death.

When flying at high altitude, the pilot wears an oxygen mask.

This is why without artificially adding oxygen to the air that pilots breathe during high-altitude flights, it would be impossible to reach the modern flight ceiling.

At an altitude of 4.5-5 thousand meters, pilots have to use breathing masks, into which a little oxygen is added from a can to the inhaled air. As the flight altitude increases, the amount of oxygen added to the mask increases. This ensures normal breathing for the aircraft crew.

Divers also use oxygen for breathing when working underwater. In an atmosphere of suffocating gases, firefighters use oxygen masks, into which air from the environment does not enter at all.

The main consumers of oxygen in nature are flora and fauna. But plants and animals consume oxygen only for breathing, while humans also use it to satisfy their domestic needs and in industry.