Mountain sickness is no joke! Altitude sickness Oxygen content at altitude.

May 29 marks exactly 66 years since the first ascent of the highest mountain in the world - Everest. After many attempts by different expeditions in 1953, New Zealander Edmund Hillary and Nepalese Sherpa Tenzing Norgay reached the world peak - 8848 meters above sea level.

To date, more than nine thousand people have already conquered Everest, while more than 300 have died during the ascent. Will a person turn around 150 meters before conquering the summit and go down if another climber becomes ill, and is it possible to climb Everest without oxygen - in our material.

Conquer the summit or save someone else's life

There are more and more people wishing to conquer the highest peak of the world every year. They are not afraid of the price of climbing, measured in tens of thousands of dollars (only one climbing permit costs $11,000, as well as the services of a guide, Sherpas, overalls and equipment), nor the risk to health and life. At the same time, many go completely unprepared: they are attracted by the romance of the mountains and the blind desire to conquer the peak, and this is the hardest test of survival. For the spring season 2019, there are already 10 people on Everest. According to media reports, a total of 20 people died in the Himalayas this spring, which is more than in all of 2018.

Of course, there is a lot of commerce in extreme tourism now, and climbers with many years of experience also note this. If earlier the queue for climbing Everest had to wait for years, now getting permission for the next season is not a problem. This spring alone, Nepal has sold 381 lifting licenses. Because of this, many hours of queues of tourists formed on the approaches to the top of the mountain, and this is at heights that are critical for life. There are situations when oxygen runs out or there are not enough physical resources of the body to stay in such conditions, and people can no longer walk, someone dies. In cases where one of the members of the group became ill, the rest have a question: leave him and continue on his way to achieve the goal for which they have been preparing all their lives, or turn around and go downhill, saving the life of another person?

According to mountaineer Nikolai Totmyanin, who has made more than 200 ascents (including five ascents of eight-thousanders and 53 ascents of seven-thousanders), it is not customary in Russian groups in mountain expeditions to leave a person who cannot go further. If someone becomes ill and there are big health risks, then the whole group turns around and goes down. This happened more than once in his practice: it happened that he had to deploy the entire expedition 150 meters from the goal (by the way, Nikolai himself climbed to the top of Everest twice without an oxygen tank).

There are situations when it is impossible to save a person. But just leaving him and continuing to move, knowing that he could die or spoil his health - this, according to our concepts, is nonsense, simply unacceptable. Human life is more important than any mountain.

At the same time, Totmyanin notes that it is different on Everest, since commercial groups from different countries are gathered there: “Others, for example, the Japanese, do not have such principles. Everyone is there for himself and is aware of the measure of responsibility that he can stay there forever ". Another important point: non-professional climbers have no sense of danger, they do not see it. And being in extreme situation when there is little oxygen, the body is limited to any activity, including mental. “In such a situation, people make inadequate decisions, therefore, it is impossible to entrust a person with a decision on whether to continue moving or not. This should be done by the leader of the group or expedition,” sums up Totmyanin.

oxygen starvation

What happens to a person at such a height? Imagine that you yourself decided to conquer the summit. Due to the fact that we get used to high atmospheric pressure, living in a city almost on a plateau (for Moscow, this is an average of 156 meters above sea level), getting into a mountainous area, our body experiences stress.

This is because the mountain climate is, first of all, low atmospheric pressure and more rarefied air than at sea level. Contrary to popular belief, the amount of oxygen in the air does not change with height, only its partial pressure (voltage) decreases.

That is, when we breathe rarefied air, oxygen is not absorbed as well as at low altitudes. As a result, the amount of oxygen entering the body decreases - a person experiences oxygen starvation.

That is why when we come to the mountains, often instead of the joy of clean air overflowing our lungs, we get headaches, nausea, shortness of breath and severe fatigue even during a short walk.

Oxygen starvation (hypoxia)- the state of oxygen starvation of both the whole organism as a whole and individual organs and tissues, caused by various factors: breath holding, disease states, low oxygen content in the atmosphere.

And the higher and faster we climb, the worse the health consequences can be. At high altitudes, there is a risk of developing altitude sickness.

What are the heights?

• up to 1500 meters - low altitudes (even with hard work there are no physiological changes);
• 1500-2500 meters - intermediate (physiological changes are noticeable, blood oxygen saturation is less than 90 percent (normal), the likelihood of mountain sickness is low);
• 2500-3500 meters - high altitudes (mountain sickness develops with a rapid ascent);
• 3500-5800 meters - very high altitudes (altitude sickness often develops, blood oxygen saturation is less than 90 percent, significant hypoxemia (decrease in oxygen concentration in the blood during exercise);
• over 5800 meters - extreme heights (pronounced hypoxemia at rest, progressive deterioration, despite maximum acclimatization, permanent stay at such heights is impossible).

altitude sickness- a painful condition associated with oxygen starvation due to a decrease in the partial pressure of oxygen in the inhaled air. Occurs high in the mountains, starting at about 2000 meters and above.

Everest without oxygen

The highest peak in the world is the dream of many climbers. Awareness of the unconquered hugeness 8848 meters high has excited minds since the beginning of the last century. However, for the first time people were on its top only in the middle of the twentieth century - on May 29, 1953, the mountain finally submitted to the New Zealander Edmund Hillary and the Nepalese Sherpa Tenzing Norgay.

In the summer of 1980, a man overcame another obstacle - the famous Italian climber Reinhold Messner climbed Everest without auxiliary oxygen in special cylinders, which are used on climbs.

Many professional climbers, as well as doctors, pay attention to the difference in the sensations of the two climbers - Norgay and Messner, when they were at the top.

According to the memoirs of Tenzing Norgay, "the sun was shining, and the sky - in all my life I have not seen the sky blue! I looked down and recognized the places memorable from past expeditions ... On all sides around us were the great Himalayas ... I had never seen such a sight and never I will not see again - wild, beautiful and terrible.

And here are Messner's memories of the same peak. “I’m sinking into the snow, heavy as a stone from fatigue… But they don’t rest here.

What is the reason for such a significant difference in the description of their triumphant ascent of the two climbers? The answer is simple - Reinhold Messner, unlike Norgay and Hillary, did not breathe oxygen.

Inhaling at the top of Everest will bring three times less oxygen to the brain than at sea level. That is why most climbers prefer to conquer peaks using oxygen tanks.

On eight-thousanders (peaks above 8000 meters) there is a so-called death zone - a height at which, due to cold and lack of oxygen, a person cannot stay for a long time.

Many climbers note that doing the simplest things - tying shoes, boiling water or getting dressed - becomes extraordinarily difficult.

Our brain suffers the most during oxygen starvation. It uses 10 times more oxygen than all other parts of the body combined. Above 7500 meters, a person receives so little oxygen that there may be a violation of the blood flow to the brain and its swelling.

brain swelling - pathological process, manifested by excessive accumulation of fluid in the cells of the brain or spinal cord and intercellular space, an increase in brain volume.

At an altitude of more than 6000 meters, the brain suffers so much that temporary bouts of insanity can occur. Slow reaction can be replaced by excitement and even inappropriate behavior.

For example, the most experienced American guide and climber Scott Fisher, most likely, having received cerebral edema, at an altitude of more than 7000 meters asked to call him a helicopter for evacuation. Although in a normal state, any, even not very experienced climber, knows perfectly well that helicopters do not fly to such a height. This incident occurred during the infamous climb of Everest in 1996, when eight climbers died during a storm on the descent.

This tragedy was widely known due to the large number of dead climbers. The victims of the ascent on May 11, 1996 were 8 people, including two guides. On that day, several commercial expeditions climbed to the top at the same time. Participants of such expeditions pay money to the guides, who, in turn, provide maximum safety and comfort for their clients on the route.

Most of the participants in the 1996 climb were not professional climbers and were heavily dependent on supplemental oxygen in cylinders. According to various testimonies, 34 people simultaneously went to the summit that day, which significantly delayed the ascent. As a result, the last climber reached the summit after 16:00. The critical time for the ascent is considered to be 13:00, after this time the guides are required to turn the clients back in order to have time to go down while it is light. 20 years ago, neither of the two guides gave such an order in time.

Due to the late rise, many participants did not have oxygen for the descent, during which a strong hurricane hit the mountain. As a result, after midnight, many climbers were still on the side of the mountain. Without oxygen and due to poor visibility, they could not find their way to the camp. Some of them were rescued by professional climber Anatoly Bukreev alone. Eight people died on the mountain due to hypothermia and lack of oxygen.

About mountain air and acclimatization

And yet, our body can adapt to very difficult conditions, including high mountains. In order to be at an altitude of more than 2500-3000 meters without serious consequences, ordinary person one to four days of acclimatization is required.

As for altitudes above 5000 meters, it is practically impossible to adapt to them normally, so you can only stay at them for a limited time. The body at such heights is not able to rest and recover.

Can the health risks of being at altitude be reduced and how can this be done? As a rule, all health problems in the mountains begin due to insufficient or improper preparation of the body, namely the lack of acclimatization.

Acclimatization is the sum of adaptive-compensatory reactions of the body, as a result of which a good general condition is maintained, weight is maintained, normal working capacity and psychological state are maintained.

Many doctors and climbers believe that the best way to adjust to altitude is to climb gradually - make several ascents, reaching ever greater heights, and then descend and rest as low as possible.

Imagine a situation: a traveler who decides to conquer Elbrus, the highest peak in Europe, starts his journey from Moscow from 156 meters above sea level. And in four days it turns out to be 5642 meters.

And although adaptation to altitude is genetically inherent in us, such a negligent climber faces several days of heart palpitations, insomnia and headaches. But for a climber who plans to climb at least a week, these problems will be minimized.

While a resident of the mountainous regions of Kabardino-Balkaria will not have them at all. In the blood of highlanders from birth, there are more erythrocytes (red blood cells), and the lung capacity is on average two liters more.

How to protect yourself in the mountains when skiing or hiking

• Gradually gain altitude and avoid sudden elevation changes;
• If you feel unwell, reduce the time of skiing or walking, make more stops for rest, drink warm tea;
• Due to the high ultraviolet radiation you can get a retinal burn. To avoid this in the mountains, you need to use Sunglasses and headdress;
• Bananas, chocolate, muesli, cereals and nuts help fight oxygen starvation;
• Alcoholic drinks at altitude should not be consumed - they increase dehydration of the body and exacerbate the lack of oxygen.

Another interesting and, at first glance, obvious fact is that in the mountains a person moves much more slowly than on the plain. In normal life, we walk at a speed of about 5 kilometers per hour. This means that we cover a distance of a kilometer in 12 minutes.

To climb to the top of Elbrus (5642 meters), starting from a height of 3800 meters, a healthy acclimatized person on average will need about 12 hours. That is, the speed will drop to 130 meters per hour compared to normal.

Comparing these figures, it is not difficult to understand how seriously altitude affects our body.

Tenth tourist dies on Everest this spring

Why the higher the colder

Even those who have never been in the mountains know one more feature of the mountain air - the higher, the colder. Why is this happening, because closer to the sun, the air, on the contrary, should warm up more.

The thing is that we feel heat not from the air, it heats up very badly, but from the surface of the earth. That is, a ray of the sun comes from above, through the air and does not heat it.

And the earth or water receives this beam, heats up quickly enough and gives off heat upwards, to the air. Therefore, the higher we are from the plain, the less heat we receive from the earth.

Inna Lobanova, Natalia Loskutnikova

Mountains attract people with their beauty and grandeur. Ancient, like eternity itself, beautiful, mysterious, bewitching the mind and heart, they do not leave anyone indifferent. Breathtaking views of mountain peaks covered with never-melting snow, slopes covered with forests, alpine meadows are pulling back everyone who has ever spent a holiday in the mountains.

It has long been observed that people in the mountains live longer than in the plains. Many of them, living to a ripe old age, retain good spirits and clarity of mind. They get sick less and recover faster after illnesses. Women of the middle mountains retain the ability to bear children much longer than women of the plains.

Breathtaking views of the mountains are complemented by the purest air, which is so pleasant to breathe in deeply. Mountain air clean and filled with aromas of healing herbs and flowers. It does not contain dust, industrial soot and exhaust gases. They breathe easily and it seems that you can not breathe in any way.

Mountains attract a person not only with their beauty and grandeur, but also with a steady improvement in well-being, a noticeable increase in efficiency, a surge of strength and energy. In the mountains, the air pressure is less than in the plains. At an altitude of 4 kilometers, the pressure is 460 mmHg, and at an altitude of 6 km - 350 mmHg. With an increase in altitude, the air density decreases, and the amount of oxygen in the inhaled volume decreases accordingly, but paradoxically, this has a positive effect on human health.

Oxygen oxidizes our body, contributes to aging and the occurrence of a host of diseases. At the same time, without it, life is impossible. Therefore, if we want to significantly extend life, we need to achieve a reduction in the flow of oxygen into the body, but not too little and not too much. In the first case, there will be no therapeutic effect, and in the second case, you can harm yourself. Such a golden mean is the mountain air of the middle mountains: 1200 - 1500 meters above sea level, where the oxygen content is approximately 10%.

At present, it has already been clearly established that there is only one factor that prolongs a person's life in the mountains - this is mountain air, the oxygen content of which is lowered and this has a highly beneficial effect on the body.

The lack of oxygen causes a restructuring in work various systems body (cardiovascular, respiratory, nervous), causes the reserve forces to turn on. This, as it turned out, is very effective, inexpensive, and most importantly for everyone. affordable way recovery and health promotion. When the amount of oxygen in the inhaled air decreases, a signal about this is transmitted through special receptors to the respiratory center of the medulla oblongata, and from there it goes to the muscles. The work of the chest and lungs intensifies, the person begins to breathe more often, respectively, the ventilation of the lungs and the delivery of oxygen to the blood improve. There is an increase in heart rate, which increases blood circulation, and oxygen reaches the tissues faster. This is facilitated by the release of new red blood cells into the blood, and, consequently, the hemoglobin contained in them.

This is what explains beneficial effect mountain air on the vitality of a person. Coming to the mountain resorts, many notice that their mood improves, vitality are activated.

But if you climb higher into the mountains, where the mountain air contains even less oxygen, the body will react to its lack in a completely different way. Hypoxia (lack of oxygen) will already be dangerous, and the nervous system will suffer first of all, and if oxygen is not enough to maintain the brain, a person may lose consciousness.

In the mountains, solar radiation is much stronger. This is due to the high transparency of air, since its density, the content of dust and water vapor in it decreases with height. solar radiation kills many harmful microorganisms living in the air and decomposes organic matter. But most importantly, solar radiation ionizes the mountain air, contributing to the formation of ions, including negative oxygen and ozone ions.

For the normal functioning of our body in the air we breathe, both negatively and positively charged ions must be present, and in a strictly defined ratio. Violation of this balance in any direction has a very adverse effect on our well-being and health. At the same time, negatively charged ions, according to modern scientific data, are necessary for a person as well as vitamins in food.

In rural air, the concentration of ions of both charges on a sunny day reaches 800-1000 per 1 cubic cm. In some mountain resorts, their concentration rises to several thousand. Therefore, the mountain air has a healing effect on most living beings. Many of the centenarians of Russia live in the mountains. Another effect of rarefied air is an increase in the body's resistance to the damaging effects of radiation. However, on high altitudes the share of ultraviolet radiation increases sharply. Impact ultraviolet rays on the human body is very large. Possible skin burns. They adversely affect the retina of the eye, causing sharp pain and sometimes temporary blindness. To protect the eyes, it is necessary to use goggles with light-protective glasses, and to protect the face, wear a hat with wide brim.

AT recent times in medicine, methods such as orotherapy (treatment with mountain air) or normobaric hypoxic therapy (treatment with rarefied air with a low oxygen content) are gaining popularity. It is well established that with the help of mountain air it is possible to prevent as well as treat the following diseases: occupational diseases associated with lesions of the upper respiratory tract, various forms allergic and immunodeficiency states, bronchial asthma, a wide group of diseases of the nervous system, diseases of the musculoskeletal system, diseases of the cardiovascular system, diseases of the gastrointestinal tract, skin diseases. Hypoxic therapy excludes side effects both without drug method treatment.

According to the degree of impact of climatic and geographical factors on a person, the existing classification subdivides (conditionally) mountain levels into:

Lowlands - up to 1000 m. Here a person does not experience (compared to the area located at sea level) the negative effect of a lack of oxygen even during hard work;

Middle Mountains - ranging from 1000 to 3000 m. Here, under conditions of rest and moderate activity, no significant changes occur in the body of a healthy person, since the body easily compensates for the lack of oxygen;

Highlands - over 3000 m. These heights are characterized by the fact that even at rest in the body of a healthy person, a complex of changes caused by oxygen deficiency is detected.

If at medium altitudes the human body is affected by the whole complex of climatic and geographical factors, then at high mountains, the lack of oxygen in the tissues of the body, the so-called hypoxia, is of decisive importance.

Highlands, in turn, can also be conditionally divided (Fig. 1) into the following zones (according to E. Gippenreiter):

a) Full acclimatization zone - up to 5200-5300 m. In this zone, due to the mobilization of all adaptive reactions, the body successfully copes with oxygen deficiency and the manifestation of other negative factors height effects. Therefore, here it is still possible to have long-term posts, stations, etc., that is, to live and work permanently.

b) Zone of incomplete acclimatization - up to 6000 m. Here, despite the commissioning of all compensatory-adaptive reactions, the human body can no longer fully counteract the influence of height. With a long (for several months) stay in this zone, fatigue develops, a person weakens, loses weight, atrophy of muscle tissues is observed, activity decreases sharply, the so-called high-altitude deterioration develops - a progressive deterioration in the general condition of a person with prolonged stay at high altitudes.

c) Adaptation zone - up to 7000 m. The adaptation of the body to altitude here is short, temporary. Even with a relatively short stay (on the order of two or three weeks) at such altitudes, adaptation reactions become depleted. In this regard, the body shows clear signs of hypoxia.

d) Zone of partial adaptation - up to 8000 m. When staying in this zone for 6-7 days, the body cannot provide the necessary amount of oxygen even to the most important organs and systems. Therefore, their activities are partially disrupted. Thus, the reduced efficiency of systems and organs responsible for replenishing energy costs does not ensure the restoration of strength, and human activity is largely due to reserves. At such altitudes, severe dehydration of the body occurs, which also worsens its general condition.

e) Limit (lethal) zone - over 8000 m. Gradually losing resistance to the action of heights, a person can stay at these heights due to internal reserves only for an extremely limited time, about 2 - 3 days.

The above values ​​of the altitudinal boundaries of the zones are, of course, average values. Individual tolerance, as well as a number of factors outlined below, can change the indicated values ​​\u200b\u200bfor each climber by 500 - 1000 m.

The body's adaptation to altitude depends on age, sex, physical and mental state, degree of fitness, degree and duration of oxygen starvation, intensity of muscle effort, and the presence of high-altitude experience. An important role is played by the individual resistance of the organism to oxygen starvation. Previous diseases, malnutrition, insufficient rest, lack of acclimatization significantly reduce the body's resistance to mountain sickness - a special condition of the body that occurs when inhaling rarefied air. Great importance has a speed of climb. These conditions explain the fact that some people feel some signs of mountain sickness already at relatively low altitudes - 2100 - 2400 m, others are resistant to them up to 4200 - 4500 m, but when climbing to a height of 5800 - 6000 m signs of altitude sickness, expressed in varying degrees appear in almost all people.

The development of mountain sickness is also influenced by some climatic and geographical factors: increased solar radiation, low air humidity, prolonged low temperatures and their sharp difference between night and day, strong winds, the degree of electrification of the atmosphere. Since these factors depend, in turn, on the latitude of the area, the distance from the water spaces and the similar reasons, then the same height in different mountainous regions of the country has a different effect on the same person. For example, in the Caucasus, signs of mountain sickness can appear already at altitudes of 3000-3500 m, in Altai, Fann mountains and Pamir-Alai - 3700 - 4000 m, Tien Shan - 3800-4200 m and Pamir - 4500-5000 m.

Signs and effects of altitude sickness

Altitude sickness can manifest itself suddenly, especially in cases where a person has significantly exceeded the limits of his individual tolerance in a short period of time, has experienced excessive overstrain in conditions of oxygen starvation. However, most mountain sickness develops gradually. Its first signs are general fatigue, which does not depend on the amount of work performed, apathy, muscle weakness, drowsiness, malaise, dizziness. If a person continues to remain at a height, then the symptoms of the disease increase: digestion is disturbed, frequent nausea and even vomiting are possible, respiratory rhythm disorder, chills and fever appear. The recovery process is rather slow.

In the early stages of the development of the disease, no special treatment measures are required. Most often, after active work and proper rest, the symptoms of the disease disappear - this indicates the onset of acclimatization. Sometimes the disease continues to progress, passing into the second stage - chronic. Its symptoms are the same, but expressed to a much stronger degree: headache can be extremely acute, drowsiness is more pronounced, the vessels of the hands are full of blood, nosebleeds are possible, shortness of breath is pronounced, rib cage becomes wide, barrel-shaped, there is increased irritability, loss of consciousness is possible. These signs speak of serious illness and the need for urgent transportation of the patient down. Sometimes the listed manifestations of the disease are preceded by a stage of excitation (euphoria), which is very reminiscent of alcohol intoxication.

The mechanism of the development of mountain sickness is associated with insufficient blood oxygen saturation, which affects the functions of many internal organs and systems. Of all the tissues in the body, the nervous system is the most sensitive to oxygen deficiency. In a person who got to a height of 4000 - 4500 m and prone to mountain sickness, as a result of hypoxia, arousal first arises, expressed in the appearance of a feeling of complacency and own strength. He becomes cheerful, talkative, but at the same time loses control over his actions, cannot really assess the situation. After a while, a period of depression sets in. Gaiety is replaced by sullenness, grumpiness, even pugnacity, and even more dangerous bouts of irritability. Many of these people do not rest in a dream: the dream is restless, accompanied by fantastic dreams that are in the nature of bad forebodings.

At high altitudes, hypoxia has a more serious effect on the functional state of higher nerve centers, causing dulling of sensitivity, impaired judgment, loss of self-criticism, interest and initiative, and sometimes memory loss. The speed and accuracy of the reaction noticeably decreases, as a result of the weakening of the processes of internal inhibition, the coordination of movement is upset. Mental and physical depression appears, expressed in slowness of thinking and actions, a noticeable loss of intuition and the ability to think logically, change conditioned reflexes. However, at the same time, a person believes that his consciousness is not only clear, but also unusually sharp. He continues to do what he was doing before the severe effects of hypoxia on him, despite sometimes dangerous consequences their actions.

The patient may have obsession, a sense of the absolute correctness of one's actions, intolerance of critical remarks, and this, if the head of the group, a person responsible for the lives of other people, finds himself in such a state, becomes especially dangerous. It has been observed that under the influence of hypoxia, people often do not make any attempts to get out of a clearly dangerous situation.

It is important to know what are the most common changes in human behavior that occur at altitude under the influence of hypoxia. In terms of frequency of occurrence, these changes are arranged in the following sequence:

Disproportionately large efforts in the performance of the task;

More critical attitude towards other participants of the trip;

Unwillingness to do mental work;

Increased irritability of the senses;

Touchiness;

Irritability with comments on work;

Difficulty concentrating;

Slow thinking;

Frequent, obsessive return to the same topic;

Difficulty in remembering.

As a result of hypoxia, thermoregulation can also be disturbed, due to which, in some cases, at low temperatures, the production of heat by the body decreases, and at the same time, its loss through the skin increases. Under these conditions, a person with mountain sickness is more susceptible to cooling than other participants in the trip. In other cases, chills and an increase in body temperature by 1-1.5 ° C are possible.

Hypoxia also affects many other organs and systems of the body.

Respiratory system.

If at rest a person at a height does not experience shortness of breath, lack of air or difficulty breathing, then during physical exertion at high altitude, all these phenomena begin to be noticeably felt. For example, one of the participants in climbing Everest took 7-10 full breaths and exhalations for each step at an altitude of 8200 meters. But even with such a slow pace of movement, he rested for up to two minutes every 20-25 meters of the path. Another participant of the ascent in one hour of movement, while being at an altitude of 8500 meters, climbed along a fairly easy section to a height of only about 30 meters.

Working capacity.

It is well known that any muscle activity, and especially intense, is accompanied by an increase in blood supply to the working muscles. However, if in flat conditions required amount The body can provide oxygen relatively easily, then with the rise to a great height, even with the maximum use of all adaptive reactions, the supply of oxygen to the muscles is disproportionate to the degree of muscle activity. As a result of this discrepancy, oxygen starvation develops, and under-oxidized metabolic products accumulate in the body in excess quantities. Therefore, human performance decreases sharply with increasing height. So (according to E. Gippenreiter) at an altitude of 3000 m it is 90%, at an altitude of 4000 m. -80%, 5500 m- 50%, 6200 m- 33% and 8000 m- 15-16% of the maximum level of work done at sea level.

Even at the end of work, despite the cessation of muscle activity, the body continues to be in tension, consuming some time increased amount oxygen in order to eliminate the oxygen debt. It should be noted that the time during which this debt is liquidated depends not only on the intensity and duration of muscle work, but also on the degree of training of a person.

Second, although less important reason reducing the body's performance is an overload of the respiratory system. It is the respiratory system, by strengthening its activity up to a certain time, that can compensate for the sharply increasing oxygen demand of the body in a rarefied air environment.

Table 1

However, the possibilities of pulmonary ventilation have their own limit, which the body reaches before the maximum working capacity of the heart occurs, which reduces the required amount of oxygen consumed to a minimum. Such limitations are explained by the fact that a decrease in the partial pressure of oxygen leads to an increase in pulmonary ventilation, and, consequently, to an increased "washout" of CO 2 from the body. But a decrease in the partial pressure of CO 2 reduces the activity of the respiratory center and thereby limits the volume of pulmonary ventilation.

At altitude, pulmonary ventilation reaches limit values already at the average load for normal conditions. So maximum amount less intensive work for a certain time, which a tourist can perform in high mountains, and recovery period after work in the mountains is longer than at sea level. However, with a long stay at the same altitude (up to 5000-5300 m) due to the acclimatization of the body, the level of working capacity increases.

The digestive system.

At altitude, appetite changes significantly, absorption of water and nutrients decreases, excretion gastric juice, functions change digestive glands, which leads to disruption of the processes of digestion and assimilation of food, especially fats. As a result, a person loses weight dramatically. So, during one of the expeditions to Everest, climbers who lived at an altitude of more than 6000 m within 6-7 weeks, lost in weight from 13.6 to 22.7 kg. At a height, a person can feel an imaginary feeling of fullness in the stomach, bursting in the epigastric region, nausea, diarrhea that is not amenable to drug treatment.

Vision.

At altitudes of about 4500 m normal visual acuity is possible only at a brightness 2.5 times greater than normal for flat conditions. At these heights, there is a narrowing of the peripheral field of vision and a noticeable "fogging" of vision in general. At high altitudes, the accuracy of fixing the gaze and the correctness of determining the distance also decrease. Even in mid-mountain conditions, vision weakens at night, and the period of adaptation to darkness lengthens.

pain sensitivity

as hypoxia increases, it decreases up to its complete loss.

Dehydration of the body.

The excretion of water from the body, as is known, is carried out mainly by the kidneys (1.5 liters of water per day), skin (1 liter), lungs (about 0.4 l) and intestines (0.2-0.3 l). It has been established that the total water consumption in the body, even in a state of complete rest, is 50-60 G at one o'clock. With average physical activity in normal climatic conditions at sea level, water consumption increases to 40-50 grams per day for every kilogram of human weight. In total, on average, under normal conditions, about 3 l water. With increased muscular activity, especially in hot conditions, the release of water through the skin sharply increases (sometimes up to 4-5 liters). But intense muscular work performed in high altitude conditions, due to lack of oxygen and dry air, sharply increases pulmonary ventilation and thereby increases the amount of water released through the lungs. All this leads to total loss water for participants in difficult high-mountain trips can reach 7-10 l per day.

Statistics show that in high altitude conditions more than doubles morbidity of the respiratory system. Inflammation of the lungs often takes on a croupous form, proceeds much more severely, and the resorption of inflammatory foci is much slower than in plain conditions.

Inflammation of the lungs begins after physical overwork and hypothermia. In the initial stage, there is a feeling of poor health, some shortness of breath, rapid pulse, cough. But after about 10 hours, the patient's condition deteriorates sharply: the respiratory rate is over 50, the pulse is 120 per minute. Despite taking sulfonamides, pulmonary edema develops already after 18-20 hours, which is a great danger in high altitude conditions. The first signs of acute pulmonary edema: dry cough, complaints of pressure slightly below the sternum, shortness of breath, weakness during exercise. In serious cases, there is hemoptysis, suffocation, severe confusion, followed by death. The course of the disease often does not exceed one day.

The basis for the formation of pulmonary edema at altitude is, as a rule, the phenomenon of increased permeability of the walls of the pulmonary capillaries and alveoli, as a result of which foreign substances (protein masses, blood elements and microbes) penetrate into the alveoli of the lungs. Therefore, the useful capacity of the lungs is sharply reduced in a short time. The hemoglobin of arterial blood, washing the outer surface of the alveoli, filled not with air, but with protein masses and blood elements, cannot be adequately saturated with oxygen. As a result of insufficient (below allowable rate) supplying oxygen to body tissues, a person quickly dies.

Therefore, even in case of the slightest suspicion of a respiratory disease, the group must immediately take measures to bring the sick person down as soon as possible, preferably to an altitude of about 2000-2500 meters.

The mechanism of development of mountain sickness

Dry atmospheric air contains: 78.08% nitrogen, 20.94% oxygen, 0.03% carbon dioxide, 0.94% argon and 0.01% other gases. When rising to a height, this percentage does not change, but the density of the air changes, and, consequently, the magnitude of the partial pressures of these gases.

According to the law of diffusion, gases pass from an environment with a higher partial pressure to an environment with a lower pressure. Gas exchange, both in the lungs and in human blood, is carried out due to the existing difference in these pressures.

At normal atmospheric pressure 760 mmp t. st. partial pressure of oxygen is:

760x0.2094=159 mmHg Art., where 0.2094 is the percentage of oxygen in the atmosphere, equal to 20.94%.

Under these conditions, the partial pressure of oxygen in the alveolar air (inhaled with air and entering the alveoli of the lungs) is about 100 mmHg Art. Oxygen is poorly soluble in blood, but it binds to the hemoglobin protein found in red blood cells - erythrocytes. Under normal conditions, due to the high partial pressure of oxygen in the lungs, hemoglobin in arterial blood is saturated with oxygen up to 95%.

When passing through the capillaries of tissues, hemoglobin in the blood loses about 25% of oxygen. Therefore, venous blood carries up to 70% oxygen, the partial pressure of which, as can be easily seen from the graph (Fig. 2), is

0 10 20 30 40 50 60 70 80 90 100

Partial pressure of oxygen mm .pm .cm.

Rice. 2.

at the time of flow venous blood to the lungs at the end of the circulation cycle only 40 mmHg Art. Thus, there is a significant pressure difference between venous and arterial blood, equal to 100-40=60 mmHg Art.

Between carbon dioxide inhaled with air (partial pressure 40 mmHg Art.), and carbon dioxide flowing with venous blood to the lungs at the end of the circulatory cycle (partial pressure 47-50 mmHg.), differential pressure is 7-10 mmHg Art.

As a result of the existing pressure drop, oxygen passes from the pulmonary alveoli into the blood, and directly in the tissues of the body, this oxygen diffuses from the blood into the cells (into an environment with an even lower partial pressure). Carbon dioxide, on the contrary, first passes from the tissues into the blood, and then, when venous blood approaches the lungs, from the blood into the alveoli of the lung, from where it is exhaled into the surrounding air. (Fig. 3).

Rice. 3.

With ascent to altitude, the partial pressures of gases decrease. So, at an altitude of 5550 m(corresponding to an atmospheric pressure of 380 mmHg Art.) for oxygen it is:

380x0.2094=80 mmHg Art.,

that is, it is reduced by half. At the same time, of course, the partial pressure of oxygen in the arterial blood also decreases, as a result of which not only the saturation of blood hemoglobin with oxygen decreases, but also due to a sharp reduction in the pressure difference between arterial and venous blood, the transfer of oxygen from blood to tissues worsens significantly. This is how oxygen deficiency-hypoxia occurs, which can lead to a person's illness with mountain sickness.

Naturally, a number of protective compensatory-adaptive reactions arise in the human body. So, first of all, the lack of oxygen leads to the excitation of chemoreceptors - nerve cells, which are very sensitive to a decrease in the partial pressure of oxygen. Their excitation serves as a signal for deepening and then quickening of breathing. The resulting expansion of the lungs increases their alveolar surface and thereby contributes to a more rapid saturation of hemoglobin with oxygen. Thanks to this, as well as a number of other reactions, the body receives a large number of oxygen.

However, with increased respiration, ventilation of the lungs increases, during which there is an increased excretion (“washing out”) of carbon dioxide from the body. This phenomenon is especially enhanced with the intensification of work in high altitude conditions. So, if on the plain at rest within one minute approximately 0.2 l CO 2, and during hard work - 1.5-1.7 l, then in high altitude conditions, on average, the body loses about 0.3-0.35 per minute l CO 2 at rest and up to 2.5 l during intense muscular work. As a result, there is a lack of CO 2 in the body - the so-called hypocapnia, characterized by a decrease in the partial pressure of carbon dioxide in arterial blood. But carbon dioxide plays an important role in regulating the processes of respiration, circulation and oxidation. A serious lack of CO 2 can lead to paralysis of the respiratory center, to a sharp drop in blood pressure, deterioration of the heart, and disruption of nervous activity. Thus, a decrease in CO 2 blood pressure by 45 to 26 mm. r t. reduces blood circulation to the brain by almost half. That is why cylinders designed for breathing at high altitudes are not filled with pure oxygen, and its mixture with 3-4% carbon dioxide.

A decrease in the content of CO 2 in the body disrupts the acid-base balance towards an excess of alkalis. Trying to restore this balance, the kidneys intensively remove this excess of alkalis from the body along with urine for several days. Thus, an acid-base balance is achieved at a new, lower level, which is one of the main signs of the completion of the adaptation period (partial acclimatization). But at the same time, the value of the alkaline reserve of the body is violated (decreases). In case of mountain sickness, a decrease in this reserve contributes to its further development. This is explained by the fact that a rather sharp decrease in the amount of alkalis reduces the ability of the blood to bind acids (including lactic acid) that are formed during hard work. It's in short term changes the acid-base ratio in the direction of an excess of acids, which disrupts the work of a number of enzymes, leads to disorganization of the metabolic process and, most importantly, inhibition of the respiratory center occurs in a seriously ill patient. As a result, breathing becomes shallow, carbon dioxide is not completely removed from the lungs, accumulates in them and prevents oxygen from reaching hemoglobin. At the same time, suffocation quickly sets in.

From all that has been said, it follows that although the main cause of mountain sickness is a lack of oxygen in the tissues of the body (hypoxia), the lack of carbon dioxide (hypocapnia) also plays a rather large role here.

Acclimatization

With a long stay at a height in the body, a number of changes occur, the essence of which is to preserve the normal functioning of a person. This process is called acclimatization. Acclimatization is the sum of adaptive-compensatory reactions of the body, as a result of which a good general condition is maintained, weight constancy, normal working capacity and the normal course of psychological processes are maintained. Distinguish between complete and incomplete, or partial, acclimatization.

Due to the relatively short period of stay in the mountains, mountain tourists and climbers are characterized by partial acclimatization and adaptation-short-term(as opposed to the final or long-term) adaptation of the body to new climatic conditions.

In the process of adaptation to a lack of oxygen in the body, the following changes occur:

Since the cerebral cortex is extremely sensitive to oxygen deficiency, the body in high altitude conditions primarily seeks to maintain proper oxygen supply to the central nervous system by reducing the oxygen supply to other, less important organs;

The respiratory system is also largely sensitive to a lack of oxygen. The respiratory organs react to the lack of oxygen first by deeper breathing (increasing its volume):

table 2

and then an increase in the frequency of breathing:

As a result of some reactions caused by oxygen deficiency, not only the number of erythrocytes (red blood cells containing hemoglobin) increases in the blood, but also the amount of hemoglobin itself (Fig. 4).

All this causes an increase in the oxygen capacity of the blood, that is, the ability of the blood to carry oxygen to the tissues and thus supply the tissues with the necessary amount of it increases. It should be noted that the increase in the number of erythrocytes and the percentage of hemoglobin is more pronounced if the ascent is accompanied by intense muscle load, that is, if the adaptation process is active. The degree and rate of growth in the number of erythrocytes and hemoglobin content also depend on geographical features certain mountain regions.

Increases in the mountains and the total amount of circulating blood. However, the load on the heart does not increase, since at the same time there is an expansion of capillaries, their number and length increase.

In the first days of a person's stay in high mountains (especially in poorly trained people), the minute volume of the heart increases, and the pulse increases. So, for physically poorly trained climbers at a height 4500m pulse increases by an average of 15, and at an altitude of 5500 m - at 20 beats per minute.

At the end of the acclimatization process at altitudes up to 5500 m all of these parameters are reduced to normal values, typical for normal activities at low altitudes. The normal functioning of the gastrointestinal tract is also restored. However, at high altitudes (more than 6000 m) pulse, respiration, the work of the cardiovascular system never decrease to a normal value, because here some organs and systems of a person are constantly under conditions of a certain tension. So, even during sleep at altitudes of 6500-6800 m the pulse rate is about 100 beats per minute.

It is quite obvious that for each person the period of incomplete (partial) acclimatization has a different duration. Much faster and with less functional deviations, it occurs in physically healthy people aged 24 to 40 years. But in any case, a 14-day stay in the mountains under conditions of active acclimatization is sufficient for a normal organism to adapt to new climatic conditions.

To exclude the possibility of a serious illness with mountain sickness, as well as to reduce the time of acclimatization, the following set of measures can be recommended, carried out both before leaving for the mountains and during the trip.

Before a long alpine journey, including passes above 5000 m in the route of its route m, all candidates must be subjected to a special medical-physiological examination. Persons who do not tolerate oxygen deficiency, are physically insufficiently prepared, and who have suffered pneumonia, tonsillitis or serious influenza during the pre-trek training period, should not be allowed to participate in such trips.

The period of partial acclimatization can be shortened if the participants of the upcoming trip, a few months before going to the mountains, start regular general physical training, especially to increase the endurance of the body: long-distance running, swimming, underwater sports, skating and skiing. During such training, a temporary lack of oxygen occurs in the body, which is the higher, the greater the intensity and duration of the load. Since the body works here in conditions that are somewhat similar in terms of oxygen deficiency to staying at a height, a person develops an increased resistance of the body to a lack of oxygen when performing muscular work. In the future, in mountainous conditions, this will facilitate adaptation to height, speed up the process of adaptation, and make it less painful.

You should know that for tourists who are physically unprepared for a high-mountain trip, the vital capacity of the lungs at the beginning of the trip even slightly decreases, the maximum performance of the heart (compared to trained participants) also becomes 8-10% less, and the reaction of increasing hemoglobin and erythrocytes with oxygen deficiency is delayed .

The following activities are carried out directly during the trip: active acclimatization, psychotherapy, psychoprophylaxis, organization of appropriate nutrition, the use of vitamins and adaptogens (drugs that increase the body's performance), complete cessation of smoking and alcohol, systematic condition control health, the use of certain drugs.

Active acclimatization for climbing ascents and for high-mountain hiking trips has a difference in the methods of its implementation. This difference is explained, first of all, by a significant difference in the heights of the climbing objects. So, if for climbers this height can be 8842 m, then for the most prepared tourist groups it will not exceed 6000-6500 m(several passes in the region of the High Wall, Zaalai and some other ridges in the Pamirs). The difference lies in the fact that the ascent to the peaks along technically difficult routes takes several days, and along difficult traverses - even weeks (without significant loss of height at certain intermediate stages), while in high-mountain hiking trips that have, as a rule, a greater length, it takes less time to overcome the passes.

Lower heights, shorter stay on these W- honeycombs and a faster descent with a significant loss of altitude to a greater extent facilitate the process of acclimatization for tourists, and quite multiple the alternation of ascents and descents softens, and even stops the development of mountain sickness.

Therefore, climbers during high-altitude ascents are forced at the beginning of the expedition to allocate up to two weeks for training (acclimatization) ascents to lower peaks, which differ from the main object of ascent to a height of about 1000 meters. For tourist groups, whose routes pass through passes with a height of 3000-5000 m, special acclimatization exits are not required. For this purpose, as a rule, it is enough to choose such a route route, in which during the first week - 10 days the height of the passes passed by the group would increase gradually.

Since the greatest malaise caused by the general fatigue of a tourist who has not yet become involved in hiking life is usually felt in the first days of the hike, even when organizing a day trip at this time, it is recommended to conduct classes on movement technique, on the construction of snow huts or caves, as well as exploration or training exits. to height. These practical exercises and exits should be carried out at a good pace, which makes the body react faster to rarefied air, more actively adapt to changes in climatic conditions. N. Tenzing's recommendations are interesting in this regard: at a height, even at a bivouac, you need to be physically active - warm snow water, monitor the condition of the tents, check equipment, move more, for example, after setting up the tents, take part in the construction of a snow kitchen, help distribute prepared food by tents.

Important in the prevention of mountain sickness is proper organization nutrition. At an altitude of over 5000 m diet daily nutrition must have at least 5000 large calories. The content of carbohydrates in the diet should be increased by 5-10% compared to the usual diet. In areas associated with intense muscle activity, first of all, an easily digestible carbohydrate - glucose should be consumed. Increased carbohydrate intake contributes to the formation of more carbon dioxide, which the body lacks. The amount of fluid consumed in high altitude conditions and, especially, when performing intensive work associated with movement along difficult sections of the route, should be at least 4-5 l per day. This is the most decisive measure in the fight against dehydration. In addition, an increase in the volume of fluid consumed contributes to the removal of underoxidized metabolic products from the body through the kidneys.

The body of a person who prolonged intensive work in high mountains requires an increased (2-3 times) amount of vitamins, especially those that are part of the enzymes involved in the regulation of redox processes and are closely related to metabolism. These are B vitamins, where B 12 and B 15 are the most important, as well as B 1, B 2 and B 6. So, vitamin B 15, in addition to the above, helps to increase the body's performance at altitude, greatly facilitating the performance of large and intense loads, increases the efficiency of oxygen use, activates oxygen metabolism in tissue cells, and increases altitude stability. This vitamin enhances the mechanism of active adaptation to a lack of oxygen, as well as fat oxidation at altitude.

Except them, important role vitamins C, PP and folic acid in combination with iron glycerophosphate and metacil also play. Such a complex has an effect on an increase in the number of red blood cells and hemoglobin, that is, an increase in the oxygen capacity of the blood.

The acceleration of adaptation processes is also influenced by the so-called adaptogens - ginseng, eleutherococcus and acclimatizin (a mixture of eleutherococcus, lemongrass and yellow sugar). E. Gippenreiter recommends the following complex of drugs that increase the body's adaptability to hypoxia and facilitate the course of mountain sickness: eleutherococcus, diabazole, vitamins A, B 1, B 2, B 6, B 12, C, PP, calcium pantothenate, methionine, calcium gluconate, calcium glycerophosphate and potassium chloride. The mixture proposed by N. Sirotinin is also effective: 0.05 g of ascorbic acid, 0.5 G. citric acid and 50 g of glucose per dose. We can also recommend a dry blackcurrant drink (in briquettes of 20 G), containing citric and glutamic acids, glucose, sodium chloride and phosphate.

How long, upon returning to the plain, does the organism retain the changes that have occurred in it during the process of acclimatization?

At the end of the journey in the mountains, depending on the altitude of the route, the changes acquired in the process of acclimatization in the respiratory system, blood circulation and the composition of the blood itself pass quickly enough. So, increased content hemoglobin decreases to normal in 2-2.5 months. Over the same period, the increased ability of the blood to carry oxygen also decreases. That is, the acclimatization of the body to the height lasts only up to three months.

True, after repeated trips to the mountains, a kind of “memory” is developed in the body for adaptive reactions to altitude. Therefore, at the next trip to the mountains, its organs and systems, already along the “beaten paths”, quickly find the right way to adapt the body to a lack of oxygen.

Help for mountain sickness

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

For headaches, take Citramon, Pyramidone (no more than 1.5 g per day), Analgin (no more than 1 G for a single dose and 3 g per day) or their combinations (troychatka, quintuple);

With nausea and vomiting - Aeron, sour fruits or their juices;

For insomnia - noxiron, when a person falls asleep badly, or Nembutal, when sleep is not deep enough.

When using drugs in high altitude conditions, special care should be taken. First of all, this applies to biological active substances(phenamine, phenatin, pervitin), stimulating 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 already during the descent, when the duration of the upcoming movement is not great. An overdose of these drugs leads to exhaustion of the nervous system, to a sharp decrease in efficiency. An overdose of these drugs is especially dangerous in conditions of prolonged oxygen deficiency.

If the group decided to urgently descend the sick participant, then during the descent it is necessary not only to systematically monitor the patient's condition, but also regularly inject antibiotics and drugs that stimulate the human heart and respiratory activity (lobelia, cardiamine, corazol or norepinephrine).

SUN EXPOSURE

Sun burns.

From prolonged exposure to the sun on the human body, sunburns form on the skin, which can cause a painful condition for a tourist.

Solar radiation is a stream of rays of the visible and invisible spectrum, which have different biological activity. When exposed to the sun, there is a simultaneous effect of:

Direct solar radiation;

Scattered (arrived due to the scattering of part of the flow of direct solar radiation in the atmosphere or reflection from clouds);

Reflected (as a result of the reflection of rays from surrounding objects).

The magnitude of the flow of solar energy falling on one or another specific area of ​​​​the earth's surface depends on the height of the sun, which, in turn, is determined by geographical latitude area, time of year and day.

If the sun is at its zenith, then its rays travel the shortest path through the atmosphere. At a standing height of the sun of 30 °, this path doubles, and at sunset - 35.4 times more than with a sheer fall of the rays. Passing through the atmosphere, especially through its lower layers containing particles of dust, smoke and water vapor in suspension, the sun's rays are absorbed and scattered to a certain extent. Therefore, the greater the path of these rays through the atmosphere, the more polluted it is, the lower the intensity of solar radiation they have.

With the rise to a height, the thickness of the atmosphere through which the sun's rays pass decreases, and the most dense, moistened and dusty lower layers are excluded. Due to the increase in the transparency of the atmosphere, the intensity of direct solar radiation increases. The nature of the change in intensity is shown in the graph (Fig. 5).

Here, the flux intensity at sea level is taken as 100%. The graph shows that the amount of direct solar radiation in the mountains increases significantly: by 1-2% with an increase for every 100 meters.

The total intensity of the direct solar radiation flux, even at the same height of the sun, changes its value depending on the season. Thus, in summer, due to an increase in temperature, increasing humidity and dustiness reduce the transparency of the atmosphere to such an extent that the magnitude of the flux at a sun height of 30 ° is 20% less than in winter.

However, not all components of the spectrum sun rays change their intensity to the same extent. The intensity increases especially ultraviolet rays are the most active physiologically: it has a pronounced maximum at a high position of the sun (at noon). The intensity of these rays this period in the same weather conditions time required for

redness of the skin, at a height of 2200 m 2.5 times, and at an altitude of 5000 m 6 times less than at an altitude of 500 winds (Fig. 6). With a decrease in the height of the sun, this intensity drops sharply. So, for a height of 1200 m this dependence is expressed by the following table (the intensity of ultraviolet rays at a sun height of 65 ° is taken as 100%):

Table4

If the clouds of the upper tier weaken the intensity of direct solar radiation, usually only to an insignificant extent, then the denser clouds of the middle and especially the lower tiers can reduce to zero. .

Diffused radiation plays a significant role in the total amount of incoming solar radiation. Scattered radiation illuminates places that are in the shade, and when the sun closes over some area with dense clouds, it creates a general daylight illumination.

The nature, intensity and spectral composition of scattered radiation are related to the height of the sun, the transparency of the air and the reflectivity of clouds.

Scattered radiation in a clear sky without clouds, caused mainly by atmospheric gas molecules, differs sharply in its spectral composition both from other types of radiation and from scattered radiation under a cloudy sky. The maximum energy in its spectrum is shifted to shorter wavelengths. And although the intensity of scattered radiation in a cloudless sky is only 8-12% of the intensity of direct solar radiation, the abundance of ultraviolet rays in the spectral composition (up to 40-50% of the total number of scattered rays) indicates its significant physiological activity. The abundance of short-wavelength rays also explains the bright blue color of the sky, the blueness of which is the more intense, the cleaner the air.

In the lower layers of the air, when the sun's rays are scattered from large suspended particles of dust, smoke and water vapor, the intensity maximum shifts to the region of longer waves, as a result of which the color of the sky becomes whitish. With a whitish sky or in the presence of a weak fog, the total intensity of scattered radiation increases by 1.5-2 times.

When clouds appear, the intensity of scattered radiation increases even more. Its value is closely related to the amount, shape and location of clouds. So, if at a high standing of the sun the sky is covered by clouds by 50-60%, then the intensity of scattered solar radiation reaches values ​​equal to the flow of direct solar radiation. With a further increase in cloudiness and especially with its compaction, the intensity decreases. With cumulonimbus clouds, it can even be lower than with a cloudless sky.

It should be borne in mind that if the flow of scattered radiation is higher, the lower the transparency of the air, then the intensity of ultraviolet rays in this type of radiation is directly proportional to the transparency of the air. In the daily course of changes in illumination, the greatest value of scattered ultraviolet radiation falls on the middle of the day, and in the annual course - in winter.

The value of the total flux of scattered radiation is also influenced by the energy of the rays reflected from the earth's surface. So, in the presence of pure snow cover, scattered radiation increases by 1.5-2 times.

The intensity of reflected solar radiation depends on the physical properties of the surface and on the angle of incidence of the sun's rays. Wet black soil reflects only 5% of the rays falling on it. This is because the reflectivity decreases significantly with increasing soil moisture and roughness. But alpine meadows reflect 26%, polluted glaciers - 30%, clean glaciers and snowy surfaces - 60-70%, and freshly fallen snow - 80-90% of the incident rays. Thus, when moving in the highlands along snow-covered glaciers, a person is affected by a reflected stream, which is almost equal to direct solar radiation.

The reflectivity of individual rays included in the spectrum of sunlight is not the same and depends on the properties of the earth's surface. So, water practically does not reflect ultraviolet rays. The reflection of the latter from the grass is only 2-4%. At the same time, for freshly fallen snow, the reflection maximum is shifted to the short-wavelength range (ultraviolet rays). You should know that the number of ultraviolet rays reflected from the earth's surface, the greater, the brighter this surface. It is interesting to note that the reflectivity of human skin for ultraviolet rays is on average 1-3%, that is, 97-99% of these rays falling on the skin are absorbed by it.

Under normal conditions, a person is faced not with one of the listed types of radiation (direct, diffuse or reflected), but with their total effect. On the plain, this total exposure under certain conditions can be more than twice the intensity of exposure to direct sunlight. When traveling in the mountains at medium altitudes, the irradiation intensity as a whole can be 3.5-4 times, and at an altitude of 5000-6000 m 5-5.5 times higher than normal flat conditions.

As has already been shown, with increasing altitude, the total flux of ultraviolet rays especially increases. At high altitudes, their intensity can reach values ​​exceeding the intensity of ultraviolet irradiation with direct solar radiation in plain conditions by 8-10 times!

Influencing open areas of the human body, ultraviolet rays penetrate the human skin to a depth of only 0.05 to 0.5 mm, causing, at moderate doses of radiation, redness, and then darkening (sunburn) of the skin. In the mountains, open areas of the body are exposed to solar radiation throughout the daylight hours. Therefore, if the necessary measures are not taken in advance to protect these areas, a body burn can easily occur.

Outwardly, the first signs of burns associated with solar radiation do not correspond to the degree of damage. This degree comes to light a little later. According to the nature of the lesion, burns are generally divided into four degrees. For the considered sunburn, in which only the upper layers of the skin are affected, only the first two (the mildest) degrees are inherent.

I - the mildest degree of burn, characterized by reddening of the skin in the burn area, swelling, burning, pain and some development of skin inflammation. Inflammatory phenomena pass quickly (after 3-5 days). Pigmentation remains in the burn area, sometimes peeling of the skin is observed.

II degree is characterized by a more pronounced inflammatory reaction: intense reddening of the skin and exfoliation of the epidermis with the formation of blisters filled with a clear or slightly cloudy liquid. Full recovery of all layers of the skin occurs in 8-12 days.

Burns of the 1st degree are treated by skin tanning: the burnt areas are moistened with alcohol, a solution of potassium permanganate. In the treatment of second degree burns, the primary treatment of the burn site is performed: rubbing with gasoline or 0.5%. ammonia solution, irrigation of the burnt area with antibiotic solutions. Considering the possibility of introducing an infection in field conditions, it is better to close the burn area with an aseptic bandage. A rare change of dressing contributes to the speedy recovery of the affected cells, since the layer of delicate young skin is not injured.

During a mountain or ski trip, the neck, earlobes, face and skin of the outer side of the hands suffer most from exposure to direct sunlight. As a result of exposure to scattered, and when moving through the snow and reflected rays, the chin, lower part of the nose, lips, skin under the knees are burned. Thus, almost any open area of ​​the human body is prone to burns. On warm spring days, when driving in the highlands, especially in the first period, when the body is not yet tanned, in no case should one allow a long (over 30 minutes) exposure to the sun without a shirt. gentle skin the abdomen, lower back and lateral surfaces of the chest are most sensitive to ultraviolet rays. It is necessary to strive to ensure that in sunny weather, especially in the middle of the day, all parts of the body are protected from exposure to all types of sunlight. In the future, with repeated repeated exposure to ultraviolet radiation, the skin acquires a tan and becomes less sensitive to these rays.

The skin of the hands and face is the least susceptible to UV rays.

Rice. 7

But due to the fact that it is the face and hands that are the most exposed parts of the body, they suffer most from sunburn. Therefore, on sunny days, the face should be protected gauze bandage. In order to prevent the gauze from getting into the mouth during deep breathing, it is advisable to use a piece of wire (length 20-25 cm, diameter 3 mm), passed through the bottom of the bandage and curved in an arc (rice. 7).

In the absence of a mask, the parts of the face that are most susceptible to burns can be covered with a protective cream such as "Ray" or "Nivea", and lips with colorless lipstick. To protect the neck, it is recommended to hem double-folded gauze to the headgear from the back of the head. Take special care of your shoulders and hands. If with a burn

shoulders, the injured participant cannot carry a backpack and all his load falls on other comrades with an additional weight, then in case of a burn of the hands, the victim will not be able to provide reliable insurance. Therefore, on sunny days, wearing a long-sleeved shirt is a must. The back of the hands (when moving without gloves) must be covered with a layer of protective cream.

snow blindness

(eye burn) occurs with a relatively short (within 1-2 hours) movement in the snow on a sunny day without goggles as a result of the significant intensity of ultraviolet rays in the mountains. These rays affect the cornea and conjunctiva of the eyes, causing them to burn. Within a few hours, pain (“sand”) and lacrimation appear in the eyes. The victim cannot look at light, even at a lit match (photophobia). There is some swelling of the mucous membrane, later blindness may occur, which, if timely measures are taken, disappears without a trace after 4-7 days.

To protect your eyes from burns, goggles should be used, the lenses of which are dark (orange, dark purple, dark green or Brown) to a large extent absorb ultraviolet rays and reduce the overall illumination of the area, preventing eye fatigue. It's good to know that Orange color improves the feeling of relief in conditions of snowfall or light fog, creates the illusion of sunlight. Green color brightens up the contrasts between brightly lit and shady areas of the area. Because bright sunlight, reflected from a white snowy surface, has a strong stimulating effect on the nervous system through the eyes, then wearing goggles with green lenses has a calming effect.

The use of goggles made of organic glass in high-altitude and ski trips is not recommended, since the spectrum of the absorbed part of the ultraviolet rays of such glass is much narrower, and some of these rays, which have the most short length waves and having the greatest physiological impact, still comes to the eyes. Prolonged exposure to such, even a reduced amount of ultraviolet rays, can eventually lead to eye burns.

It is also not recommended to take canned glasses that fit snugly to the face on a hike. Not only glasses, but also the skin of the part of the face covered by them fogs up a lot, causing an unpleasant sensation. Much better is the use of conventional glasses with sidewalls made of a wide adhesive plaster. (Fig. 8).

Rice. eight.

Participants in long hikes in the mountains must always have spare glasses at the rate of one pair for three people. In the absence of spare glasses, you can temporarily use a gauze blindfold or put cardboard tape over your eyes, making pre-narrow slits in it in order to see only a limited area of ​​\u200b\u200bthe area.

First aid for snow blindness: rest for the eyes (dark bandage), washing the eyes with a 2% solution of boric acid, cold lotions from tea broth.

Sunstroke

Severe morbid condition that suddenly occurs during long transitions as a result of many hours of exposure infrared rays direct sunlight on an uncovered head. At the same time, in the conditions of the campaign, the back of the head is exposed to the greatest influence of the rays. The outflow of arterial blood that occurs in this case and a sharp stagnation of venous blood in the veins of the brain lead to its edema and loss of consciousness.

The symptoms of this disease, as well as the actions of the first aid team, are the same as those for heat stroke.

A headgear that protects the head from exposure to sunlight and, in addition, retains the possibility of heat exchange with the surrounding air (ventilation) thanks to a mesh or a series of holes, is a mandatory accessory for a participant in a mountain trip.

Altitude sickness (the medical term is altitude hypoxia) is often caused by a lack of oxygen in the air at high altitudes and is a form of altitude sickness.

Anyone can suffer from altitude sickness. Its symptoms begin to appear in different people at different heights above sea level. Most often, climbers, skiers and tourists in high mountain areas suffer from high-altitude hypoxia. Factors contributing to altitude sickness are, first of all, the physical state and preparation of a person, as well as the rate of ascent to a specific height. Mountain sickness usually occurs at an altitude of two to three thousand meters above sea level. However, some people experience health problems even at one and a half thousand meters.

Primary symptoms of altitude sickness

Altitude hypoxia usually appears within a few hours of reaching a certain point above sea level. Symptoms of altitude sickness may include:

• headache,
• irritability,
• dizziness,
• muscle pain,
• fatigue or insomnia
• loss of appetite
• nausea or vomiting
• swelling of the face, hands and feet.

A more serious condition can cause a brain tumor and lead to hallucinations, confusion, difficulty moving (walking), severe headaches, and severe fatigue. Severe altitude sickness also causes fluid to build up in the lungs, resulting in shortness of breath even during rest. A severe form of mountain sickness is a direct threat to life, and with its symptoms, you should immediately seek medical help.

How to treat mountain sickness

Diagnosis and treatment of moderate high-altitude hypoxia is generally not required, as symptoms usually resolve within a day or two. Doctors sometimes recommend that people with altitude sickness take aspirin or ibuprofen for relief. muscle pain. Climbers take medications that prevent or treat many of the symptoms of high-altitude hypoxia.

Severe altitude sickness is a serious and life-threatening health condition that must be treated in a hospital with oxygen therapy and procedures to reduce brain tumors and the amount of fluid in the lungs. People with severe symptoms should be moved to a lower altitude.

Can altitude sickness be prevented?

The easiest way to avoid primary symptoms Altitude sickness is climbing slowly to a higher altitude, which will allow the body to get used to the lower oxygen content in the air. In the highlands, while the body gets used to the high altitude, it is important to avoid stress for the first few days and limit physical activity.

What are the causes of altitude sickness

The percentage of oxygen in the air, equal to 21, remains virtually unchanged up to 21,000 meters. The root mean square velocities of diatomic nitrogen and oxygen are very similar and therefore no change in the ratio of oxygen to nitrogen occurs. However, air density (the number of molecules of both oxygen and nitrogen per volume) decreases with altitude, and the amount of oxygen available to keep you mentally and physically active decreases at more than 3,000 meters. Although the flight altitude of modern passenger airliners does not exceed 2400 meters, some passengers on long-haul flights may experience some symptoms of altitude sickness.

Other causes of altitude sickness

The rate of ascent, the altitude reached, the amount of physical activity at high altitude, and individual susceptibility are major factors contributing to the onset of altitude hypoxia and its severity. Dehydration at high altitudes can also contribute to symptoms of altitude sickness.

Altitude hypoxia usually occurs after a rapid ascent and can usually be prevented by a slow ascent. In most cases, the symptoms are temporary and decrease with acclimatization. However, in extreme cases, altitude sickness can be a fatal condition.

Human susceptibility to height

People have different susceptibility to altitude sickness. In some healthy people, acute mountain sickness can appear at an altitude of about 2000 meters above sea level, for example, in ski resorts. Symptoms often appear 6-10 hours after getting up and usually go away within one to two days, but sometimes develop into more severe conditions. Symptoms of high-altitude hypoxia include headache, fatigue, gastric diseases, dizziness and sleep disturbance. Physical activity exacerbates the main symptoms.

The main symptoms of altitude sickness

Headache is the main symptom used to diagnose altitude sickness. A headache that occurs at altitudes above 2400 meters in combination with any one or more of the following symptoms may indicate the presence of altitude sickness:

Severe symptoms of altitude sickness

Symptoms that may indicate a life-threatening condition include:

Life-threatening symptoms of altitude sickness

The most serious symptoms of altitude sickness are due to edema (fluid buildup in tissues). At very high altitudes, people can get either high-altitude pulmonary edema or high-altitude cerebral edema. The physiological cause of altitude-induced edema has not been definitively established. Medications such as dexamethasone can temporarily relieve symptoms so you can get back down the mountain on your own.

high-altitude pulmonary edema

High-altitude pulmonary edema can progress rapidly and often leads to lethal outcome. Symptoms include fatigue, severe shortness of breath at rest, and a cough that is initially dry but may progress to pink, frothy sputum. Descending to lower altitudes relieves the symptoms listed above.

high-altitude cerebral edema

Cerebral edema is a life-threatening condition that can lead to coma or death. Symptoms include headache, fatigue, blurred vision, dysfunction Bladder, bowel dysfunction, loss of coordination, paralysis on one side of the body and confusion. Descending to lower altitudes can save the life of a person with cerebral edema.

How to avoid altitude sickness

Slow climb - The best way avoid altitude sickness. Also avoid strenuous physical activity, such as skiing, mountain hiking, etc. Since alcohol tends to cause dehydration, which exacerbates high-altitude hypoxia, the best option is the complete avoidance of alcohol in the first 24 hours in the mountains.

Altitude acclimatization

Altitude acclimatization is the process of adaptation of the body to a decrease in oxygen in the air by more high levels to avoid altitude sickness. For climbers, a typical acclimatization regimen might be to stay a few days at base camp, ascend to a higher camp (slowly) and then return to base camp. The subsequent ascent includes an overnight stay. This process is repeated several times, each time with an increase in time spent at high altitudes, which will allow the body to adjust to the oxygen levels. Once the climber acclimates to a given altitude, the process is repeated at higher levels. The main rule is not to climb more than 300 meters a day before bedtime. That is, in one day you can climb from 3000 to 4500 meters, but then you should go back down to 3300 meters for an overnight stay. Special high-altitude equipment that produces hypoxic (oxygen-reduced) air can be used to acclimatize at high altitude, reducing acclimatization time.

Medical treatment of mountain sickness

Some drugs can help you make a quick ascent to a height of more than 2700 meters. However, experts, in particular experts medical center Everest Base Camp cautions against their daily use as a substitute for the reasonable acclimatization schedule described above, except in certain cases where rapid ascent is necessary or due to terrain.

Randomized controlled trials highlight that some medications that may help prevent altitude sickness, despite their popularity, are not always effective means prevention of high-altitude hypoxia, and, for example, phosphodiesterase inhibitors can even aggravate headache in mountain sickness.

oxygen enrichment

In high mountain environments, oxygen enrichment can counteract altitude-related hypoxia. At an altitude of 3400 meters, a 5 percent increase in oxygen concentration through an oxygen concentrator and the existing ventilation system provide an effective simulation of an altitude of 3000 meters.

Other methods of dealing with altitude sickness

Increasing water intake may also aid in acclimatization by replacing fluid lost by panting with dry air at altitude, but excessive amounts are not beneficial and can cause dangerous hyponatremia.

Oxygen from gas cylinders or liquid containers is delivered directly through a nasal cannula or mask. Oxygen concentrators based on pressure adsorption can be used to generate oxygen if electricity is available. Stationary oxygen concentrators typically use PSA technology, which is characterized by performance degradation at lower barometric pressures at higher altitudes. One way to compensate for performance degradation is to use a hub with more bandwidth. There are also portable oxygen concentrators that can be used on car power. direct current or internal batteries. The use of high purity oxygen by one of these methods increases the partial pressure of oxygen by increasing the FiO 2 .

In addition, the use of nitric oxide helps to eliminate the symptoms of altitude sickness.

What to do with obvious symptoms of altitude sickness

The only reliable treatment, and in many cases the only affordable option is the descent. Attempts to treat or stabilize an injured person in situ at altitude are dangerous unless they are under strict supervision and under proper medical conditions. However, the following treatments may be used if the location and circumstances permit:

Denial of responsibility: The information provided in this article on altitude sickness is intended to inform the reader only. It cannot be a substitute for the advice of a health professional.