Man is a test of heights. About the effect of altitude on the body

To begin with, let's remember the high school physics course, which explains why and how atmospheric pressure changes depending on altitude. The higher the area is above sea level, the lower the pressure there. It is very simple to explain: atmospheric pressure indicates the force with which a column of air presses on everything that is on the surface of the Earth. Naturally, the higher you rise, the lower the height of the air column, its mass and the pressure exerted will be.

In addition, at altitude the air is rarefied, it contains a much smaller number of gas molecules, which also immediately affects the mass. And we must not forget that with increasing altitude, the air is cleared of toxic impurities, exhaust gases and other “delights”, as a result of which its density decreases and atmospheric pressure drops.

Studies have shown that the dependence of atmospheric pressure on altitude differs as follows: an increase of ten meters causes a decrease in the parameter by one unit. As long as the altitude of the area does not exceed five hundred meters above sea level, changes in the pressure of the air column are practically not felt, but if you rise five kilometers, the values ​​​​will be half the optimal ones. The strength of the pressure exerted by the air also depends on the temperature, which decreases greatly when rising to a higher altitude.

For blood pressure levels and general condition human body The value of not only atmospheric, but also partial pressure, which depends on the concentration of oxygen in the air, is very important. In proportion to the decrease in air pressure, the partial pressure of oxygen also decreases, which leads to an insufficient supply of this essential element to the cells and tissues of the body and the development of hypoxia. This is explained by the fact that the diffusion of oxygen into the blood and its subsequent transportation to the internal organs occurs due to the difference in the partial pressure of the blood and the pulmonary alveoli, and when rising to a high altitude, the difference in these readings becomes significantly smaller.

How does altitude affect a person's well-being?

Main negative factor The main effect on the human body at altitude is the lack of oxygen. It is as a result of hypoxia that acute disorders heart conditions and blood vessels, increased blood pressure, digestive disorders and a number of other pathologies.

Hypertensive patients and people prone to pressure surges should not climb high into the mountains and it is advisable not to take long flights. They will also have to forget about professional mountaineering and mountain tourism.

The severity of the changes occurring in the body made it possible to distinguish several altitude zones:

• Up to one and a half to two kilometers above sea level - relatively safe zone, in which there are no special changes in the functioning of the body and the state of vitality important systems. Deterioration in well-being, decreased activity and endurance are observed very rarely.
• From two to four kilometers - the body tries to cope with oxygen deficiency on its own, thanks to increased breathing and deep breaths. Heavy physical work, which requires the consumption of large amounts of oxygen, is difficult to perform, but light exercise is well tolerated for several hours.
• From four to five and a half kilometers - the state of health noticeably worsens, performing physical work is difficult. Psycho-emotional disorders appear in the form of high spirits, euphoria, and inappropriate actions. When staying at such a height for a long time, headaches, a feeling of heaviness in the head, problems with concentration, and lethargy occur.
• From five and a half to eight kilometers - exercise physical work impossible, the condition worsens sharply, the percentage of loss of consciousness is high.
• Above eight kilometers - at this altitude a person is able to maintain consciousness for a maximum of several minutes, after which deep fainting and death follows.

For flow in the body metabolic processes Oxygen is needed, the deficiency of which at altitude leads to the development of altitude sickness. The main symptoms of the disorder are:

• Headache.
• Increased breathing, shortness of breath, lack of air.
• Nose bleed.
• Nausea, attacks of vomiting.
• Joint and muscle pain.
• Sleep disorders.
• Psycho-emotional disorders.

At high altitudes, the body begins to experience a lack of oxygen, as a result of which the functioning of the heart and blood vessels is disrupted, arterial and intracranial pressure increases, and vital internal organs fail. To successfully overcome hypoxia, you need to include nuts, bananas, chocolate, cereals, and fruit juices in your diet.

Effect of altitude on blood pressure levels

When rising to a high altitude, thin air causes an increase in heart rate and an increase in blood pressure. However, with a further increase in altitude, blood pressure levels begin to decrease. A decrease in the oxygen content in the air to critical values ​​causes depression of cardiac activity and a noticeable decrease in pressure in the arteries, while in the venous vessels the levels increase. As a result, a person develops arrhythmia and cyanosis.

Not long ago, a group of Italian researchers decided for the first time to study in detail how altitude affects blood pressure levels. To conduct research, an expedition to Everest was organized, during which the participants’ pressure levels were determined every twenty minutes. During the hike, an increase in blood pressure during ascent was confirmed: the results showed that the systolic value increased by fifteen, and the diastolic value by ten units. It was noted that the maximum blood pressure values ​​were determined at night. The effect of antihypertensive drugs at different altitudes was also studied. It turned out that the drug under study effectively helped at an altitude of up to three and a half kilometers, and when rising above five and a half it became absolutely useless.

Altitude test.
Mountain sickness and other dangers when climbing.

Weather conditions and the condition of the route are the two main problems that worry experienced mountain climbers. high mountains. It is better not to start climbing in bad weather or with a bad forecast. The majority of those who died on the slopes of the mountain were those who simply lost the right path in conditions of lack of visibility. The presence or absence of areas of bare ice on the route determines its technical complexity. In good conditions, sometimes you can even get by without cats. But when a belt of “bottle” ice appears in winter, or more often in spring, even outstanding ice climbers get excited. Organizing insurance over a long section seems like too much time. Therefore, they walk very, very carefully, but without insurance. One wrong move and... Fly to the end of the slope. Fortunately, there is almost never ice in the summer.
If you are lucky in these two positions, then climbing Elbrus may not be difficult for you at all. But no matter how lucky you are, you will certainly encounter one problem. This is your body's reaction to changes. external conditions. To altitude, to solar radiation, to cold, to other unfavorable factors. For most climbers, this becomes a test of their altitude tolerance.

For a long time, scientists and climbers have encountered in the mountains the phenomenon of decreased performance of the body. Scientifically speaking, there is a sharp increase or rather a breakdown in the cardiovascular activity, respiratory, digestive and nervous systems, especially in the first days of staying at altitude. In many cases, this led to the development of acute mountain sickness, when there was a direct threat to human life. At the same time, the higher the climbers climbed into the mountains, the more pronounced adverse symptoms. At the same time, local residents accompanying the climbers reacted much more calmly to the changes climatic factors. On the one hand, this indicated the individual nature of the reaction to height. On the other hand, it led to conclusions about the possibility of adaptation to unfavorable factors.

Practice has led to the conclusion that preliminary acclimatization is necessary, carried out in a certain sequence. It usually involves a gradual climb to altitude with a descent at night to lower altitudes. As always, there is theory and there is practice.
Theoretically, we recommend climbing Elbrus after at least 7-10 days of active walking at lower altitudes. But in practice, people often go climbing 4-5 days after arriving in the mountains. What can we do, our behavior is determined by social conditions. Constant shortage time is the cost of the modern lifestyle.

Here's what science says about the adverse factors of high altitudes.

1. Temperature. With increasing altitude, the average annual air temperature gradually decreases by 0.5 °C for every 100 m, and in different seasons of the year and in different geographical areas it decreases differently: in winter it is slower than in summer, amounting to 0.4 °C and 0, respectively. 6°C. In the Caucasus, the average decrease in temperature in summer is 6.3-6.8° per 1 vertical kilometer, but in practice it can be up to 10 degrees.

2. Air humidity. Humidity is the amount of water vapor in the air. Since the pressure of saturated water vapor is determined only by air temperature, in mountainous areas where the temperature is low, the partial pressure of water vapor is also low. Already at an altitude of 2000 m, air humidity is half that at sea level, and at high mountain altitudes the air becomes almost “dry”. This circumstance increases the loss of fluid by the body not only through evaporation from the surface of the skin, but also through the lungs during hyperventilation. Hence the importance of ensuring an adequate drinking regime in the mountains, because... Dehydration of the body reduces performance.

3. Solar radiation. At mountain heights, the intensity of the radiant energy of the sun increases greatly due to the great dryness and transparency of the atmosphere and its lower density. When rising to an altitude of 3000 m, the total solar radiation increases by an average of 10% for every 1000 m. Biggest changes are detected by ultraviolet radiation: its intensity increases by an average of 3-4% for every 100 m of increase in altitude. The body is affected by both visible (light) and invisible (infrared and the most biologically active ultraviolet) sun rays. In moderate doses it can be beneficial to the body. However, excessive exposure to sunlight can cause burns, sunstroke, cardiovascular and nervous disorders, exacerbation of chronic inflammatory processes. As you gain altitude, the increased biological effectiveness of ultraviolet radiation can cause skin erythema, keratitis (inflammation of the cornea of ​​the eyes). Creams, masks, glasses are mandatory things for climbers on Elbrus. Although there are people who can easily do without it. Their skin is of a different type.

4. Atmospheric pressure. As altitude increases, atmospheric pressure drops, while the concentration of oxygen, as well as the percentage of other gases within the atmosphere, remain constant. Compared to sea level, atmospheric pressure at an altitude of 3000 m is lower by 31% and at an altitude of 4000 m - by 39%, and at the same altitudes it increases from high to low latitudes and in the warm period it is usually higher than in the cold . A drop in atmospheric pressure is closely related to the main cause of altitude sickness, lack of oxygen. In scientific language this is called a decrease in the partial pressure of oxygen. The experimental results show that at an altitude of 3000 m the amount of O2 in the inhaled air decreases by one third and at an altitude of 4000 m by half. All this leads to undersaturation of hemoglobin with oxygen; it enters the tissues an insufficient amount and a phenomenon called hypoxia develops. This is actually the body’s reaction to this phenomenon.

Preparing for the ascent. Training. Sometimes you can hear stories about how a person does not train and calmly goes on high-altitude climbs better than “regular” athletes. Well, legends can be retold and retold. In any case, leading an unsportsmanlike lifestyle, not training your body, is a path that we do not welcome. For a successful climb to Elbrus, what is important, first of all, is endurance, the readiness of the heart, lungs and muscles for long-term work. Skiing and long-distance running are the best training tools. On the other hand, you should pay attention to the opposite point. Athletes in peak condition are often very vulnerable to infectious diseases. Therefore, we recommend that for people who have mastered large volumes of training, reduce the load about a week before leaving for the mountains. And avoid competitions with maximum effort at this time. In addition, the body must accumulate fat reserves.

Collection. Equipment. Many people take all kinds of gatherings lightly and even try to boast about their sloppiness. Mountaineering should make such people more organized. Here, every item taken or not taken can cost your life, not only to you, but also to your fellow climbers. It is imperative to prepare yourself for thorough preparation and selection of equipment. Make a list and practice each item in advance, including medications. Do not hesitate to contact the organizers with questions about the selection of equipment and medical support for the ascent.

Nutrition during preparation. It is recommended to prepare yourself the way athletes prepare for a responsible start. The last week before departure there should be a lot of food, it should be varied with a lot of carbohydrates. It is recommended to take a course of vitamin complexes. Their choice is great and recommending something specific means advertising. These should be multivitamins and they should be taken strictly according to the doses indicated in the accompanying papers. Or better yet, on the recommendation of your personal doctor.

In the mountains, a period of acclimatization. First days. Don't worry ahead of time. A normal healthy body must demonstrate its response to changing conditions. You should not panic if immediately upon arriving in the mountains you feel unwell, dizzy, lack of appetite, etc. Each person's reaction is unique. But in general, a healthy person can be advised not to interfere with his body’s ability to adapt to new stressful conditions. In theory, the body should draw the right conclusions on its own. How can you stop him? First of all, you should avoid taking a lot of medications, let your head hurt a little, let the nausea go away on its own. It is not recommended to overeat and drink large quantities of alcoholic beverages during acclimatization. Leave this for the final part of the expedition, and in the first days you can limit yourself to 50-100 grams, which can help relieve tension. You should continue the course of taking multivitamins that you started on the plain. The body will need many different chemical elements in order to cope with the upcoming test.

Nutrition during the acclimatization period.
During this period, due to changes in the functioning of the body, there may be disruptions in appetite. You should not force anything to eat. Eat what you want. It is advisable to eat a lot of varied and natural foods. However, it should be remembered that the basis of the diet under hypoxic conditions should be carbohydrates. The most easily digestible carbohydrate is sugar. In addition, it has a positive effect on protein and fat metabolism, which changes in high altitude conditions. Daily requirement in sugar during ascent increases to 200-250 g. It is recommended that each participant in ascent to heights consume ascorbic acid with glucose. It is advisable that at all exits the flasks contain tea with sugar and lemon or ascorbic acid.

Just before the ascent. Sleeping mode. Due to the lack of oxygen, for many people, sleep in the first nights at altitudes of 3500 - 4200 meters turns into torture. And before climbing, it is advisable to get a good night's sleep during the day. It is recommended to have a hearty lunch and go to bed immediately after lunch. The exit is carried out in the middle of the night, by which time you need to feel completely rested. Prepare everything you need in advance, especially equipment. Health protection equipment: glasses, preferably spare ones, a mask against cold and wind, a special protective face cream with protection factor 15, a special lipstick cream, individual medications. As a rule, the group has a person responsible for the public first aid kit, most often this is a guide-leader. However, accessing it during ascent is not always convenient. So, we recommend having with you: aspirin, ascorbic acid and throat lozenges, such as Minton.

Biostimulants. If on the days of acclimatization it is better to avoid medications, then on the day of ascent this recommendation does not apply so strictly. You must be 100% ready and give it your all on this particular day. Of course, if you have a severe headache, you should immediately stop climbing. But if the pain is minor, it should be relieved by taking appropriate tablets. We recommend having with you previously tested means of increasing performance, which can roughly be classified as biostimulants. For example, tinctures of ginseng, eleutherococcus, lemongrass, drugs such as Pantolex. However, it should be taken into account that there is no such remedy yet that could significantly increase the body’s performance for a long time. Stronger performance-enhancing tablets that have a short-term effect should be kept as an ED in a general first aid kit. You should rely, first of all, on your will, on your ability to endure and endure.

Water mode. Great importance for high-altitude acclimatization, prevention of mountain sickness and preservation of performance, has proper organization water and drinking regime. Water in physiological processes the body plays a big role. It makes up 65-70% of body weight (40-50 l). Human need for water in normal conditions is 2.5 l. At altitude it must be brought to 3.5-4.5 liters, which will fully ensure physiological needs body. Water metabolism is closely related to mineral metabolism, especially to the metabolism of sodium chloride and potassium chloride. At the same time, water and drinking deficiency is also added to hypoxia.

Sometimes they talk about the dangers of indiscriminate intake of water while climbing. However, this may only apply to easy mountain hikes that follow trails past numerous streams. On a mountain, when you can only consume the water you carry with you, there simply cannot be an excess amount. It is necessary to consume liquid in the form of hot tea with sugar and possibly other additives. To keep the tea hot, you need to have a thermos as much as possible. good quality. Unfortunately, even expensive thermoses do not always pass muster. Test it before heading to the mountains. Regarding your drinking regimen, you can only give the following advice. In the morning, before going out, drink a little more tea than you want. And calculate the contents of the thermos so that it is enough for descent. It is at the end of the working day that a sip of tea can make a huge difference in energizing and maintaining much-needed alertness to danger.

Acute altitude sickness. It cannot be allowed. This condition develops on Elbrus mainly in irresponsible people. You need to carefully monitor your body and don’t be shy to stop climbing and turn back before the disease takes over. acute stage. During the ascent, the guide or leader must carefully monitor the condition of his comrades. The appearance of symptoms of hidden or light forms mountain sickness requires an immediate reduction in physical activity and pace of movement, increasing rest periods, drink plenty of fluids. It is recommended to take ascorbic acid (0.1 g). For headaches, it is better to use aspirin.

In case of severe or moderate mountain sickness, it is necessary to stop climbing and urgently and quickly reduce the altitude. Exactly this effective medicine. In this case, if possible, the patient should be deprived of a backpack and heavy clothing. Artificial oxygen may become the most important therapeutic agent. However, so far its use on Elbrus is limited to isolated experiments. Perhaps the patient should be given a diuretic, preferably dicarb, and in acute cases furosemide can be given. Other simple drugs are aspirin and ascorbic acid. Stimulants can be caffeine or, better yet, nootropil. Of the new drugs recommended by German researchers as a preventive measure for pulmonary edema caused by mountain sickness, these are Nifedipin and Salmeperol (an asthma medicine).

Latest research on altitude sickness. About three years ago, the whole world received a sensational message about the use of a famous drug from a slightly different area - Viagra - as a prophylactic agent. It is believed that this is a miracle cure, it blocks some enzymes and dramatically improves peripheral circulation. Including in the lung area. Later it turned out that this message was not limited to a single loud sensation for the press. And Viagra has become part of the means that many Everest climbers take with them. Moreover, this is a dual-use product.
Last year, a large medical experiment was carried out on the slopes of Monterosa in the Alps. 22 climbers acted as test subjects. The main result was proof of the practical uselessness of use as a prophylactic agent. hormonal drugs based on cortisone. The popular drug dexamethasone, which in the film “Vertical Limit” climbers carried with them in suitcases, was recognized by experts as “at least pointless to use.”

According to the largest expert on medical support for climbing Everest, American Professor Peter Hackett, in the coming years we can expect a breakthrough in research regarding altitude sickness. The process of the body’s reaction to the unfavorable factors of high altitude is determined by the activity of such complex mechanism like the brain. The medicine of the near future will deal with the impact on it. We will allow ourselves to improvise a little on this topic. Indeed, the main thing in mountaineering is in the head and in the heart. This is the ability to perceive the beauty and grandeur of nature, love for the mountains. If this is not the case, then it is better to give up mountaineering. And if you have this, then you will find the strength to cope with your own ailments.

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

Low mountains - up to 1000 m. Here a person does not experience (compared to areas located at sea level) the negative effects 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. What is characteristic of these altitudes is that even under conditions of rest, a complex of changes caused by oxygen deficiency is detected in the body of a healthy person.

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

The 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, thanks to the mobilization of all adaptive reactions, the body successfully copes with oxygen deficiency and the manifestation of other negative factors of the influence of altitude. Therefore, it is still possible to locate long-term posts, stations, etc. here, that is, live and work permanently.

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

c) Adaptation zone - up to 7000 m. The body's adaptation to altitude here is short-lived and temporary. Already with a relatively short (about two to three weeks) stay at such altitudes, the adaptation reactions become exhausted. In this regard, clear signs of hypoxia appear in the body.

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

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

The given values ​​of the altitudinal boundaries of the zones have, of course, average values. Individual tolerance, as well as a number of factors outlined below, can change the indicated values ​​for each climber by 500 - 1000 m.

The body's adaptation to altitude depends on age, gender, physical and mental state, degree of training, degree and duration of oxygen starvation, intensity of muscle effort, and the presence of high-altitude experience. The individual resistance of the body to oxygen starvation also plays an important role. Previous illnesses, poor nutrition, insufficient rest, lack of acclimatization significantly reduce the body’s resistance to mountain sickness - special condition organism that occurs when inhaling rarefied air. The speed of climb is of great importance. 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 altitudes of 5800 - 6000 m signs of mountain 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, and the degree of electrification of the atmosphere. Since these factors depend, in turn, on the latitude of the area, distance from water areas, and so on similar reasons, then the same altitude in different mountainous regions of the country has a different effect on the same person. For example, in the Caucasus, signs of mountain sickness may appear already at altitudes of 3000-3500 m, in Altai, Fan Mountains and Pamir-Alai - 3700 - 4000 m, Tien Shan - 3800-4200 m and Pamir - 4500-5000 m.

Signs and nature of the effects of mountain sickness

Mountain 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, or has experienced excessive overexertion in conditions of oxygen starvation. However, most often, mountain sickness develops gradually. Its first signs are general fatigue, regardless of the amount of work performed, apathy, muscle weakness, drowsiness, malaise, and dizziness. If a person continues to remain at altitude, 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 healing process is quite slow.

In the early stages 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, moving into the second stage - chronic. Its symptoms are the same, but much more pronounced. strong degree: the headache can be extremely acute, drowsiness is more pronounced, the vessels of the hands are overflowing with blood, nosebleeds are possible, shortness of breath is pronounced, rib cage becomes wide, barrel-shaped, observed increased irritability, loss of consciousness is possible. These signs indicate serious illness and the need to urgently transport the patient down. Sometimes the listed manifestations of the disease are preceded by a stage of excitement (euphoria), very reminiscent of alcohol intoxication.

The mechanism of development of mountain sickness is associated with insufficient oxygen saturation of the blood, which affects the functions of many internal organs and systems. Of all the body tissues, the nervous tissue is the most sensitive to oxygen deficiency. In a person who gets to a height of 4000 - 4500 m and prone to mountain sickness, as a result of hypoxia, excitement first arises, expressed in the appearance of a feeling of complacency and personal strength. He becomes cheerful and talkative, but at the same time loses control over his actions and cannot really assess the situation. After some time, a period of depression sets in. Cheerfulness is replaced by gloominess, grumpiness, even pugnacity, and even more dangerous attacks of irritability. Many of these people do not rest in their sleep: sleep is restless, accompanied by fantastic dreams that have the nature of 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 internal inhibition processes, movement coordination is disrupted. Mental and physical depression, expressed in slowness of thinking and action, 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 he was seriously affected by hypoxia, despite sometimes dangerous consequences of your actions.

The sick person may develop obsession, a feeling of the absolute correctness of one’s actions, intolerance to critical remarks, and this, if the group leader, a person responsible for the lives of other people, finds himself in such a state, becomes especially dangerous. It has been noticed that under the influence of hypoxia, people often make no attempts to get out of an obviously dangerous situation.

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

Disproportionately great effort when completing a task;

A more critical attitude towards other travel participants;

Reluctance to do mental work;

Increased irritability of the senses;

Touchiness;

Irritability when receiving comments about work;

Difficulty concentrating;

Slowness of thinking;

Frequent, obsessive return to the same topic;

Difficulty remembering.

As a result of hypoxia, thermoregulation can also be disrupted, which is why, in some cases, at low temperatures, the body’s heat production decreases, and at the same time, its loss through the skin increases. Under these conditions, a person suffering from altitude sickness is more susceptible to chilling than other participants in the trip. In other cases, chills and an increase in body temperature by 1-1.5 ° C may occur.

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

Respiratory system.

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

Performance.

It is well known that any muscular activity, and especially intense activity, is accompanied by an increase in blood supply to the working muscles. However, if in plain conditions the body can provide the required amount of oxygen relatively easily, then with an ascent to a high altitude, 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, a person’s performance decreases sharply with increasing altitude. 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 performed at sea level.

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

The second, although less important reason a decrease in the body's performance is an overload of the respiratory system. Exactly respiratory system by increasing its activity up to a certain time, it can compensate for the sharply increasing oxygen demand of the body in rarefied air conditions.

Table 1

Height in meters	Increase in pulmonary ventilation in % (with the same work)

However, the capabilities of pulmonary ventilation have their own limit, which the body reaches before the maximum performance of the heart occurs, which reduces the required amount of oxygen consumed to a minimum. Such restrictions are explained by the fact that a decrease in the partial pressure of oxygen leads to increased pulmonary ventilation, and consequently to increased “washing out” 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 maximum values ​​even when performing an average load for normal conditions. Therefore, the maximum amount of intensive work in a certain time that a tourist can perform in high altitude conditions is less, and the 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 acclimatization of the body, the level of performance increases.

Digestive system.

At altitude, appetite changes significantly, absorption of water and nutrients decreases, and excretion gastric juice, the functions of the digestive glands change, which leads to disruption of the processes of digestion and absorption of food, especially fats. As a result, the person suddenly loses weight. Thus, during one of the expeditions to Everest, climbers who lived at an altitude of more than 6000 m within 6-7 weeks, lost weight from 13.6 to 22.7 kg. At altitude, a person may feel an imaginary feeling of fullness in the stomach, distension in the epigastric region, nausea, and diarrhea that cannot be treated with medication.

Vision.

At altitudes of about 4500 m normal visual acuity is possible only at a brightness 2.5 times higher than normal for plain conditions. At these altitudes, there is a narrowing of the peripheral field of vision and a noticeable “fogging” of vision as a whole. At high altitudes, the accuracy of gaze fixation and the correctness of determining distance also decreases. Even in mid-altitude conditions, vision weakens at night, and the period of adaptation to darkness lengthens.

Pain sensitivity

as hypoxia increases, it decreases until it is completely lost.

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 a person’s weight. In total, on average, under normal conditions, about 3 are released per day. l water. With increased muscle activity, especially in hot conditions, the release of water through the skin increases sharply (sometimes up to 4-5 liters). But intense muscular work performed in high altitude conditions, due to a 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 the fact that the total loss of water among participants in difficult high-altitude trips can reach 7-10 l per day.

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

Pneumonia begins after physical fatigue and hypothermia. IN initial stage there is poor health, some shortness of breath, rapid pulse, and cough. But after about 10 hours, the patient’s condition worsens sharply: the respiratory rate is over 50, the pulse is 120 per minute. Despite taking sulfonamides, pulmonary edema develops within 18-20 hours, which poses a great danger in high altitude conditions. First signs acute edema lungs: dry cough, complaints of compression slightly below the sternum, shortness of breath, weakness on exercise. In serious cases, hemoptysis, suffocation, severe disorder consciousness, after which death occurs. The course of the disease often does not exceed one day.

The formation of pulmonary edema at altitude is usually based on 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 within a short time. Hemoglobin 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, a person quickly dies from insufficient (below the permissible norm) oxygen supply to the body’s tissues.

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

Mechanism of development of mountain sickness

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

According to the law of diffusion, gases move from a medium with a higher partial pressure to a medium with a lower pressure. Gas exchange, both in the lungs and in the human blood, occurs due to the existing difference in these pressures.

At normal atmospheric pressure 760 mmp t. Art. The 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 the blood, but it is bound by 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 tissue capillaries, blood hemoglobin 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), amounts to

0 10 20 30 40 50 60 70 80 90 100

Oxygen partial pressure mm.pm.cm.

Rice. 2.

at the moment of flow venous blood to the lungs at the end of the circulatory cycle only 40 mmHg Art. Thus, between venous and arterial blood there is a significant pressure difference 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.), pressure drop is 7-10 mmHg Art.

As a result of the existing pressure difference, oxygen passes from the pulmonary alveoli into the blood, and directly in the tissues of the body, this oxygen from the blood diffuses 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 increasing altitude, the partial pressures of gases decrease. So, at an altitude of 5550 m(which corresponds to atmospheric pressure 380 mmHg Art.) for oxygen it is equal to:

380x0.2094=80 mmHg Art.,

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

Naturally, a number of protective compensatory and adaptive reactions occur in the human body. So, first of all, a lack of oxygen leads to the excitation of chemoreceptors - nerve cells that are very sensitive to a decrease in the partial pressure of oxygen. Their excitement serves as a signal for deepening and then increased breathing. The expansion of the lungs that occurs in this case 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, a large amount of oxygen enters the body.

However, with increased breathing, ventilation of the lungs increases, during which increased removal (“washing out”) of carbon dioxide from the body occurs. This phenomenon is especially intensified with 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 per minute the body loses about 0.3-0.35 l CO 2 at rest and up to 2.5 l during intense muscular work. As a result, a lack of CO 2 occurs in the body - the so-called hypocapnia, characterized by a decrease in the partial pressure of carbon dioxide in the arterial blood. But carbon dioxide plays an important role in regulating the processes of respiration, blood circulation and oxidation. A serious lack of CO 2 can lead to paralysis of the respiratory center, a sharp drop in blood pressure, deterioration of heart function, and disruption of nervous activity. Thus, a decrease in blood pressure CO 2 by an amount from 45 to 26 mm. r t.st. 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 CO 2 content in the body disrupts the acid-base balance towards an excess of alkalis. Trying to restore this balance, the kidneys spend several days intensively removing this excess of alkalis from the body along with urine. This achieves acid-base balance at a new, lower level, which is one of the main signs of the end of the adaptation period (partial acclimatization). But at the same time, the amount of the body’s alkaline reserve is disrupted (decreased). When suffering from mountain sickness, a decrease in this reserve contributes to its further development. This is explained by the fact that a fairly sharp decrease in the amount of alkalis reduces the blood’s ability to bind acids (including lactic acid) formed during hard work. This is in short term changes the acid-base ratio towards an excess of acids, which disrupts the functioning 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. In this case, 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 fairly large role here.

Acclimatization

During a long stay at altitude, a number of changes occur in the body, the essence of which boils down to maintaining normal human functioning. This process is called acclimatization. Acclimatization is the sum of adaptive-compensatory reactions of the body, as a result of which good general condition is maintained, weight constancy, normal performance and the normal course of psychological processes are maintained. A distinction is made 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 final or long-term) adaptation of the body to new climatic conditions.

In the process of adapting to the 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 strives 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 highly sensitive to lack of oxygen. The respiratory organs respond to a lack of oxygen by first breathing deeper (increasing its volume):

table 2

Height, m		5000	6000
Inhaled volume air, ml			1000

and then by increasing the respiratory rate:

Table 3
	Breathing rate
Nature of movement	at sea level	at an altitude of 4300 m
Walking at speed 6,4 km/hour	17,2
Walking at 8.0 speed km/hour	20,0

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 increases and thus supply the tissues with the necessary amount. It should be noted that the increase in the number of red blood cells 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 red blood cells and hemoglobin content also depend on geographical features certain mountainous regions.

The total amount of circulating blood also increases in the mountains. However, the load on the heart does not increase, since at the same time the capillaries expand, their number and length increase.

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

Upon completion of the acclimatization process at altitudes up to 5500 m all these parameters are reduced to normal values ​​characteristic of ordinary activities at low altitudes. The normal functioning of the gastrointestinal tract is also restored. However, at high altitudes (more than 6000 m) pulse, respiration, and work of the cardiovascular system never decrease to normal value, because here some human organs and systems 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. It occurs much faster and with fewer functional deviations in physically healthy people aged from 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 body to adapt to new climatic conditions.

To eliminate the possibility of serious mountain sickness, as well as to shorten the acclimatization time, we can recommend the following set of measures, carried out both before leaving for the mountains and during the trip.

Before a long high-mountain trip, including passes above 5000 in the route of your route m, all candidates must be subjected to a special medical and physiological examination. Persons who cannot tolerate oxygen deficiency, who are physically insufficiently prepared, and who have suffered from pneumonia, sore throat or serious flu during the pre-trip preparation period should not be allowed to participate in such hikes.

The period of partial acclimatization can be shortened if the participants of the upcoming trip begin regular general physical training in advance, several months before going to the mountains, especially to increase the body’s endurance: long-distance running, swimming, underwater sports, skating and skiing. During such training, a temporary lack of oxygen occurs in the body, which is higher, the greater the intensity and duration of the load. Since the body here works in conditions somewhat similar in terms of oxygen deficiency to being at altitude, 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 altitude, speed up the adaptation process, and make it less painful.

You should know that among tourists who are physically unprepared for high-altitude travel, the vital capacity of the lungs at the beginning of the hike even decreases somewhat, the maximum performance of the heart (compared to trained participants) also becomes 8-10% less, and the reaction of increasing hemoglobin and red blood cells with oxygen deficiency is delayed .

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

Active acclimatization for mountaineering and for high-mountain hiking trips has differences in the methods of its implementation. This difference is explained, first of all, by the 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 area of ​​the High Wall, Trans-Alay and some others ridges in the Pamirs). The difference lies in the fact that climbing to the peaks along technically difficult routes takes several days, and along complex traverses even weeks (without a significant loss of altitude at individual intermediate stages), while in high-mountain hiking trips, which have as a rule, they are longer, and less time is spent on overcoming the passes.

Lower altitudes, shorter stay at these W- honeycombs and a faster descent with a significant loss of altitude greatly facilitate the acclimatization process for tourists, and quite multiple alternating ascents and descents softens, or even stops, the development of mountain sickness.

Therefore, climbers during high-altitude ascents are forced to allocate up to two weeks at the beginning of the expedition for training (acclimatization) ascents to lower peaks, which differ from the main object of ascent to an altitude of about 1000 meters. For tourist groups whose routes pass through passes with an altitude of 3000-5000 m, no special acclimatization exits are required. For this purpose, as a rule, it is sufficient to choose a route such that during the first week - 10 days the height of the passes traversed by the group would gradually increase.

Since the greatest discomfort caused by the general fatigue of a tourist who has not yet become involved in the 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 techniques, on the construction of snow huts or caves, as well as exploration or training trips to height. Specified practical lessons and exits must be done at a good pace, which forces the body to react more quickly to thin air and to more actively adapt to changes in climatic conditions. N. Tenzing’s recommendations are interesting in this regard: at altitude, even in a bivouac, you need to be physically active - heat snow water, monitor the condition of tents, check equipment, move more, for example, after setting up tents, take part in the construction of a snow kitchen, help distribute ready-made food by tents.

Proper nutrition is also essential in the prevention of mountain sickness. At an altitude of over 5000 m diet daily nutrition must have at least 5000 large calories. The carbohydrate content in the diet should be increased by 5-10% compared to normal nutrition. In areas associated with intense muscle activity, you should first consume an easily digestible carbohydrate - glucose. Increased consumption of carbohydrates 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 to combat dehydration. In addition, an increase in the volume of fluid consumed promotes the removal of under-oxidized metabolic products from the body through the kidneys.

The human body performing long-term intensive work in high altitude conditions requires an increased (2-3 times) amount of vitamins, especially those that are part of enzymes involved in the regulation of redox processes and closely related to metabolism. These are B vitamins, where the most important are B 12 and B 15, as well as B 1, B 2 and B 6. Thus, vitamin B 15, in addition to what has been said, helps to increase the body’s performance at altitude, significantly 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 lack of oxygen, as well as the oxidation of fats at altitude.

Except them, important role Vitamins C, PP and folic acid play a role in combination with iron glycerophosphate and metacil. This complex has an effect on increasing the number of red blood cells and hemoglobin, that is, increasing 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, Schisandra and yellow sugar). E. Gippenreiter recommends the following complex of drugs that increase the body’s adaptability to hypoxia and alleviate 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 lemon and glutamic acid, glucose, sodium chloride and sodium phosphate.

How long after returning to the plain does the body retain the changes that occurred in it during the process of acclimatization?

At the end of a trip in the mountains, depending on the altitude of the route, changes in the respiratory system, blood circulation and the composition of the blood itself acquired during the process of acclimatization pass quite quickly. So, increased content hemoglobin levels decrease to normal within 2-2.5 months. Over the same period, the increased ability blood to carry oxygen. That is, the body’s acclimatization to altitude lasts only up to three months.

True, after repeated trips to the mountains, the body develops a kind of “memory” for adaptive reactions to altitude. Therefore, the next time he goes to the mountains, his organs and systems are found faster along “beaten paths.” Right way to adapt the body to a lack of oxygen.

Providing assistance with mountain sickness

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

For headaches, take citramon, pyramidon (no more than 1.5 g per day), analgin (no more than 1 G for a single dose and 3 g per day) or combinations thereof (troika, quintuple);

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.

When using medications at high altitudes, special care should be taken. First of all, this applies to biological active substances(phenamine, phenatine, 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 during the descent, when the duration of the upcoming movement is not long. An overdose of these drugs leads to depletion of the nervous system, to sharp decline 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).

SUN EXPOSURE

Sunburn.

From prolonged exposure to the sun on the human body, sunburn forms on the skin, which can cause painful condition tourist

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

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 reflection of rays from surrounding objects).

The amount of solar energy flow falling on a particular area of ​​the earth's surface depends on the altitude of the sun, which, in turn, is determined by the geographical latitude of this area, the time of year and day.

If the sun is at its zenith, then its rays travel the shortest path through the atmosphere. At a sun altitude of 30°, this path doubles, and at sunset - 35.4 times more than with a vertical incidence of the rays. Passing through the atmosphere, especially through its lower layers, which contain suspended particles of dust, smoke and water vapor, the sun's rays are absorbed and scattered to a certain extent. Therefore, the longer the path of these rays through the atmosphere, the more polluted it is, the lower the intensity of solar radiation they have.

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

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

The total intensity of the direct solar radiation flux, even at the same altitude of the sun, changes its value depending on the season. Thus, in summer, due to rising temperatures, increasing humidity and dust reduce the transparency of the atmosphere so much that the flow value at a sun altitude of 30° is 20% less than in winter.

However, not all components of the spectrum of sunlight change their intensity to the same extent. The intensity increases especially sharply 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 the time required for

redness of the skin, at an altitude 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). As the altitude of the sun decreases, 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 altitude of 65° is taken as 100%):

Table4

Height of the sun, degrees.
Ultraviolet ray intensity,%		76,2	35,3	13,0

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

Scattered radiation plays a significant role in the total amount of incoming solar radiation. Scattered radiation illuminates places in the shade, and when the sun is obscured by dense clouds over an area, it creates general daylight illumination.

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

Scattered radiation in a clear sky without clouds, caused mainly by atmospheric gas molecules, is sharply different in its spectral composition both from other types of radiation and from scattered radiation in a cloudy sky. The maximum energy in its spectrum is shifted to the region of shorter waves. And although the intensity of scattered radiation under 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 bright blue color the sky, the bluer of which is more intense the cleaner the air.

In the lower layers of air, when solar rays are scattered from large suspended particles of dust, smoke and water vapor, the maximum intensity shifts to the region of longer waves, as a result of which the color of the sky becomes whitish. In a whitish sky or in the presence of light 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 magnitude is closely related to the number, shape and location of clouds. So, if when the sun is high, the sky is covered by clouds by 50-60%, then the intensity of scattered solar radiation reaches values ​​equal to the flux of direct solar radiation. With further increase in cloudiness and especially as it thickens, the intensity decreases. With cumulonimbus clouds it can be even lower than with a cloudless sky.

It should be taken into account that if the flux 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 highest value of scattered ultraviolet radiation occurs in the middle of the day, and in the annual course - in winter.

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

The intensity of reflected solar radiation depends on physical properties surface and the angle of incidence of sunlight. Wet black soil reflects only 5% of the rays falling on it. This is because reflectivity decreases significantly with increasing soil moisture and roughness. But alpine meadows reflect 26%, polluted glaciers - 30%, clean glaciers and snow surfaces - 60-70%, and freshly fallen snow - 80-90% of the incident rays. Thus, when moving in the highlands on snow-covered glaciers, a person is exposed to a reflected flux that 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. Thus, 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-wave range (ultraviolet rays). You should know that the lighter the surface, the greater the amount of ultraviolet rays reflected from the earth's 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, scattered or reflected), but with their total impact. On the plains, 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 intensity of radiation in general 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 under direct solar radiation in plain conditions by 8-10 times!

By affecting exposed areas of the human body, ultraviolet rays penetrate human skin to a depth of only 0.05 to 0.5 mm, causing redness and then darkening (tanning) of the skin at moderate doses of radiation. In the mountains, exposed 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, body burns can easily occur.

Externally, the first signs of burns associated with solar radiation do not correspond to the degree of damage. This degree is revealed somewhat later. Based on the nature of the injury, 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 (mild) degrees are inherent.

I is the mildest degree of burn, characterized by redness 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, and sometimes peeling of the skin is observed.

Stage II is characterized by a more pronounced inflammatory reaction: intense redness of the skin and detachment of the epidermis with the formation of blisters filled with clear or slightly cloudy liquid. Complete restoration of all layers of skin occurs in 8-12 days.

First degree burns are treated by tanning the skin: the burned areas are moistened with alcohol and a solution of potassium permanganate. When treating second degree burns, primary treatment of the burn site is performed: wiping with gasoline or 0.5%. solution of ammonia, irrigating the burned area with antibiotic solutions. Considering the possibility of infection while traveling, it is better to cover the burn area with an aseptic bandage. Rarely changing the dressing promotes the rapid restoration of affected cells, since this does not damage the layer of delicate young skin.

During a mountain or ski trip, the neck, earlobes, face and skin suffer the most from exposure to direct sunlight. outside hands As a result of exposure to scattered, and when moving through the snow and reflected rays, the chin, lower part of the nose, lips, and skin under the knees are subject to burns. Thus, almost any open area of ​​the human body is susceptible to burns. On warm spring days when driving in the highlands, especially in the first period, when the body does not yet have a tan, under no circumstances should you be allowed to remain in the sun for a long time (more than 30 minutes) without a shirt. Tender skin The abdomen, lower back and sides of the chest are most sensitive to ultraviolet rays. We must 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. Subsequently, with repeated repeated exposure to ultraviolet irradiation, the skin becomes tanned and becomes less sensitive to these rays.

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

Rice. 7

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

In the absence of a mask, the parts of the face most susceptible to burns can be covered with a protective cream such as “Ray” or “Nivea”, and the lips with colorless lipstick. To protect the neck, it is recommended to sew double-folded gauze to the headdress from the back of the head. You should especially take care of your shoulders and hands. If with a burn

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

Snow blindness

(eye burn) occurs during a relatively short (within 1-2 hours) movement in the snow on a sunny day without safety glasses 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 a lit match (photophobia). Some swelling of the mucous membrane is observed, and later blindness may occur, which, if measures are taken in a timely manner, disappears without a trace in 4-7 days.

To protect your eyes from burns, you must use safety glasses with dark glasses (orange, dark purple, dark green or Brown) significantly absorb ultraviolet rays and reduce the overall illumination of the area, preventing eye fatigue. It is useful to know that orange color improves the sense of relief in conditions of snowfall or light fog and creates the illusion of sunlight. Green color brightens up the contrasts between brightly lit and shadowy areas of the area. Because bright sunlight, reflected from the white snow surface, has a strong stimulating effect on the nervous system through the eyes, then wearing safety glasses with green lenses has a calming effect.

The use of safety glasses made of organic glass in high-altitude and ski trips is not recommended, since the spectrum of the absorbed part of ultraviolet rays in such glass is much narrower, and some of these rays, which have the shortest wavelength and have the greatest physiological impact, still reach the eyes. Prolonged exposure to such, even reduced amounts of ultraviolet rays, can eventually lead to eye burns.

It is also not recommended to take canned glasses on a hike that fit tightly to your face. Not only the glass, but also the skin of the area of ​​the face covered by it fogs up heavily, causing an unpleasant sensation. Much better is the use of ordinary glasses with sides made of wide adhesive plaster (Fig. 8).

Rice. 8.

Participants of long hikes in the mountains must have spare glasses at the rate of one pair for three people. If you don’t have spare glasses, you can temporarily use a gauze blindfold or put cardboard tape over your eyes, making narrow slits in it first in order to see only a limited area of ​​​​the terrain.

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

Sunstroke

A severe painful condition that suddenly occurs during long treks as a result of many hours of exposure to infrared rays of direct solar flow on an uncovered head. At the same time, during a hike, the back of the head is exposed to the greatest impact of rays. The resulting outflow of arterial blood and a sharp stagnation of venous blood in the veins of the brain lead to swelling and loss of consciousness.

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

A headdress that protects the head from exposure to sunlight and, in addition, maintains 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.

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 affectionate nicknames: miner or acclimukha. 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 you are planning to conquer the next peak, take a professional high-altitude climber into your group and medical worker. 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 it all 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 have problems with 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 wind, 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. During this period the heart undergoes increased load: It increases the number of blood cycles in 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 bad work brain Hence - clouding of consciousness, hallucinations, behavioral disturbances, etc. Hypoxia also affects 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 next 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 good reaction to height.
• Stage 2. Height – 4-5.5 km. Altitude sickness manifests itself as a throbbing headache, severe nausea, 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. Vomiting does not stop, but increases new symptom: 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.

Prevention

Climbers who are going to conquer the next height must undergo training for the ascent. The risk of symptoms will be reduced by preventing mountain sickness, consisting of the following measures:

• good physical and psychological preparation;
• education;
• quality equipment;
• a well-thought-out plan for ascent and acclimatization.

Video

Additions needed...

It is well known from the physics course that with increasing altitude above sea level, atmospheric pressure decreases. If up to an altitude of 500 meters no significant changes in this indicator are observed, then when reaching 5000 meters the atmospheric pressure decreases almost by half. As atmospheric pressure decreases, the partial pressure of oxygen in the air mixture also drops, which immediately affects the performance of the human body. The mechanism of this effect is explained by the fact that blood saturation with oxygen and its delivery to tissues and organs is carried out due to the difference in partial pressure in the blood and alveoli of the lungs, and at altitude this difference decreases.

Up to an altitude of 3500 - 4000 meters, the body itself compensates for the lack of oxygen entering the lungs by increasing breathing speed and increasing the volume of inhaled air (depth of breathing). Further climb for full compensation negative impact, requires use medicines and oxygen equipment (oxygen cylinder).

Oxygen is necessary for all organs and tissues human body during metabolism. Its consumption is directly proportional to the activity of the body. Lack of oxygen in the body can lead to the development of mountain sickness, which in extreme cases - swelling of the brain or lungs - can lead to death. Mountain sickness manifests itself in symptoms such as: headache, shortness of breath, rapid breathing, in some painful sensations in muscles and joints, appetite decreases, restless sleep etc.

Altitude tolerance is a very individual indicator, determined by the characteristics of the body's metabolic processes and fitness.

Greater role in the fight against negative impact altitude plays a role in acclimatization, during which the body learns to deal with lack of oxygen.

• The body's first reaction to a decrease in pressure is an increase in heart rate, an increase in blood pressure and hyperventilation of the lungs, and the expansion of capillaries in the tissues occurs. Reserve blood from the spleen and liver is included in the blood circulation (7 - 14 days).

• The second phase of acclimatization consists of almost doubling the number of red blood cells produced by the bone marrow (from 4.5 to 8.0 million red blood cells per mm3 of blood), which leads to better tolerance to altitude.

The consumption of vitamins, especially vitamin C, has a beneficial effect at altitude.

The intensity of development of mountain sickness depending on altitude.

Height, m	Signs
800-1000	Height is easily tolerated, but some people experience slight deviations from the norm.
1000-2500	Physically untrained people experience some lethargy, slight dizziness, and increased heart rate. There are no symptoms of altitude sickness.
2500-3000	Most healthy, non-acclimatized people feel the effects of altitude, but most healthy people do not have pronounced symptoms of altitude sickness, and some experience changes in behavior: high spirits, excessive gesticulation and talkativeness, causeless fun and laughter.
3000-5000	Acute and severe (in some cases) mountain sickness occurs. The rhythm of breathing is sharply disrupted, complaints of suffocation. Nausea and vomiting often occur, and pain in the abdominal area begins. The excited state is replaced by a decline in mood, apathy, indifference to the environment, and melancholy develop. Bright pronounced signs diseases usually do not appear immediately, but during some time spent at these altitudes.
5000-7000	There is a feeling of general weakness, heaviness throughout the body, and severe fatigue. Pain in the temples. With sudden movements - dizziness. The lips turn blue, the temperature rises, blood often comes out of the nose and lungs, and sometimes stomach bleeding begins. Hallucinations occur.

2. Rototaev P. S. R79 Conquered giants. Ed. 2nd, revised and additional M., “Thought”, 1975. 283 p. from maps; 16 l. ill.