Where is it better for a hypertensive patient to live on Russian territory?

Meteorology books often describe the Earth's atmosphere as a vast ocean of air in which we all live. Various diagrams depict our planet surrounded by a huge atmospheric sea several hundred kilometers high, divided into several different layers. But the layer of our atmosphere that supports all life is actually extremely thin—just over 5 km thick. The part of our atmosphere that can be measured with some degree of accuracy rises to about 40 kilometers. Moreover, it is almost impossible to give a precise answer about where the atmosphere ultimately ends; Somewhere between 400 and 500 km there is an undefined region where the air gradually thins and eventually dissolves into the vacuum of space.

So the layer of air surrounding our planet is not that big after all. As one famous meteorologist so eloquently put it: “The Earth is not suspended in a sea of ​​air—it is suspended in a sea of ​​space, and there is an extremely thin layer of gas on its surface.”

And this gas is our atmosphere.

If a person climbs a high mountain, such as Mauna Kea on the island of Hawaii, whose peak reaches 4206 meters above sea level, there is a high risk of suffering from altitude sickness (hypoxia). Before reaching the summit, visitors stop at an intermediate camp located at an altitude of 2804 m, where they must acclimatize to the altitude before continuing further up the mountain. “Well, of course,” you might say, “everyone knows that the amount of oxygen available at such high altitudes is significantly less compared to what is available at sea level.”

But in making such a statement, you are mistaken!

In fact, 21% of the Earth's atmosphere consists of life-giving oxygen (78% is nitrogen, and the remaining 1% is other gases). And this ratio in proportions is almost the same both at sea level and high in the mountains.

The big difference is not the amount of oxygen present, but rather its density and pressure.

Air is often compared to the ocean using the term "ocean of air", and this is true because we are all literally floating in the air. Now imagine this: a tall plastic bucket is filled to the brim with water. Now make a hole in the top of the bucket. The water will drain slowly. Now make another hole at the bottom near the bottom. What will happen? Water will rapidly flow out from the bottom hole in a strong stream. The reason is the difference in pressure. The pressure exerted by the weight of the water below at the bottom of the bucket is greater than at the top, so the water is “squeezed out” more strongly from the hole below.

Likewise, the pressure of all the air above us is the force that pushes air into our lungs, thereby delivering oxygen into the bloodstream. Once this pressure is reduced (for example, when we climb a high mountain), less air enters the lungs, therefore less oxygen reaches our bloodstream, resulting in hypoxia; again, not due to a decrease in the amount of available oxygen, but due to a decrease in atmospheric pressure.

What is atmospheric pressure?

Atmospheric pressure, also called barometric pressure, is the pressure of the gaseous shell of our planet, the atmosphere, acting on all objects located in it, as well as on the earth's surface. Pressure corresponds to the force acting in the atmosphere per unit area. In a stationary atmosphere at rest, the pressure is equal to the ratio of the weight of the overlying air column to its cross-sectional area.

Simply put, this is the force with which the air around us acts on the surface of the Earth and objects.

Atmospheric pressure is expressed in several different systems of units: millimeters (or inches) of mercury, dynes (dyn) per square centimeter, millibars (mb), standard atmosphere, or pascals (Pa). Standard sea level pressure is defined as 760 mmHg (29.92 in), 1013.25 x 103 dynes per cm2, 1013.25 millibars, one standard atmosphere, or 101.325 kilopascals. 1 mmHg corresponds to approximately 133 Pa.

Standard USA atmosphere

"The 1976 United States Standard Atmosphere is an idealized representation of the Earth's atmosphere in a static state from the surface to an altitude of 1000 km." The model is based on existing international standards and mainly uses the methodology adopted by the International Standard Atmosphere (ISA). The model equations were adopted by the United States Committee on Extension to the Standard Atmosphere (COESA), which represented 29 US scientific, government, military and engineering organizations. In the model, the atmosphere is divided into seven layers up to a maximum altitude of 86 km. The main difference between the US Standard Atmosphere and the International Standard Atmosphere is the proposed temperature distribution at high altitudes, which is not considered in this calculator.

Why does atmospheric pressure occur?

Many experiments have proven that air is not weightless. The Earth's gravitational force acts on the air, which contributes to the formation of pressure.

The mass of air around the globe is not the same. Therefore, the level of atmospheric pressure also fluctuates. Areas with more air mass experience higher pressure. If there is less air (in such cases it is also called rarefied), then the pressure is lower.

Why does the weight of the atmosphere change? The secret of this phenomenon lies in the heating of air masses. The fact is that the air is heated not directly from the sun's rays, but due to heating from the earth's surface. Near it, the air heats up, expands and, becoming lighter, rises. At this time, the cooled flows become heavier and go down. This process happens constantly. Air moves from areas of high pressure to areas of low pressure. The result is wind, which has a great influence on weather and climate.

Air temperature and hypertension

Let us list what processes occur inside a person during heat:

1. Initially, under the influence of heat, the blood vessels dilate and blood pressure drops. But not for long.
2. The body begins to sweat and fluid is lost. Along with the loss of fluid, the blood thickens, the vessels narrow, the pressure increases and remains constantly high. The tension of the blood vessels and heart muscle is maintained as long as the blood remains viscous. Against the background of blood thickening and a decrease in blood pressure, clots (thrombi) form.
3. When sweating, the body loses mineral salts (potassium, magnesium).

If a hypertensive person drinks water, his blood thins, his blood pressure decreases and returns to normal. For a patient with hypertension, it is necessary not only to drink fluids, but also to replenish the supply of minerals (take pharmaceutical complexes with potassium, magnesium).

Conclusions: Hypertensive patients can tolerate heat without complications or crises. It is necessary to drink water often and maintain the body's water and electrolyte balance.

Atmospheric pressure measurement

To measure atmospheric pressure, meteorologists use a barometer.

There are two types of barometers:

• liquid;
• mechanical (aneroid barometer).

Liquid barometers are filled with mercury. This device was invented by the Italian scientist Evangelista Torricelli. In 1643 he proved that the atmosphere could be weighed using a column of mercury. This device was the very first barometer. The open end of the glass tube is placed in an open bowl of mercury. Atmospheric pressure forces the mercury to rise up the tube. At sea level, the mercury will rise (on average) to a height of 760 millimeters.

Why not use water instead of mercury? The fact is that mercury is 13.6 times denser than water. Atmospheric pressure can hold in place a vertical column of water approximately 13.6 times higher than mercury. And in order to make a water barometer, you will need a glass tube more than 10 m long!

Evangelista Torricelli - Italian mathematician and physicist, student of Galileo. Known as the author of the concept of atmospheric pressure and the successor of Galileo's work in the development of new mechanics.

On the other hand, mercury is the heaviest substance that remains liquid at ordinary temperatures. This makes the tool more convenient to use.

Aneroid barometers are more common . The design of such a device includes a metal box with rarefied air inside. When the pressure drops, the box expands. As the pressure increases, the box compresses and acts on the attached spring. The spring moves the arrow, which shows the pressure level on the scale.

Do you need medications for altitude sickness?

During repeated ascents to high altitudes, the body develops its own adaptive survival mechanisms, and the use of medications in reasonable quantities only accelerates this adaptation.

While trekking in the Himalayas, it is mandatory to take multivitamins (preferably with a complex of microelements). These substances, as catalysts, are part of enzymes and participate in redox processes. Vitamins B, C, PP and folic acid are important, having a pronounced effect on increasing the number of red blood cells and hemoglobin. Along with vitamins, you should take a complex of enzymes that improve digestion and accelerate the process of energy formation: “Pankreotin”, “Mezim”, etc.

The effectiveness of adaptation processes to hypoxia is influenced by eubiotics. These are preparations of beneficial living bacteria, which are extremely necessary for those in conditions of oxygen deficiency. Starting to take Linex, Bifiform or their equivalent two weeks before the ascent, you can restore the microflora and get more oxygen for the body.

There are many good reviews about such a means for accelerating acclimatization as diacarb. It effectively reduces intracranial pressure, but is not recommended for prophylaxis. In addition, tourists who were allergic to sulfa drugs may be allergic to diacarb. Therefore, before using any medications, consult a doctor.

Altitude sickness while hiking and climbing is no joke!
Not every tourist can cope with it easily. We recommend that you go hiking in big mountains and climb only under the guidance of experienced guides! x(x)

Increase and decrease in pressure

When the pressure exceeds 760 mmHg. Art., it is called elevated, and when the level is less than normal - reduced.

Over the course of 24 hours, several changes in atmospheric pressure occur. In the morning and evening it rises, and after 12 noon and at night it decreases. This occurs due to the fact that the air temperature changes and, accordingly, its flows move.

In winter, the highest atmospheric pressure is observed over the mainland of the Earth, because the air here has a low temperature and is very dense. In summer, the opposite situation is observed - there is minimal pressure.

On a more global scale, pressure also depends on temperature. The Earth's surface heats unevenly: the planet has a geoid (rather than perfectly round) shape and revolves around the Sun. Some parts of the planet are heating up more, others less. Because of this, atmospheric pressure is distributed zonally over the surface of the planet.

Atmospheric pressure belts

There are 3 zones where low pressure prevails, and 4 zones where high pressure prevails. The equatorial zone warms up the most, so light warm air rises and low pressure forms at the surface.

At the poles, the opposite is true: cold air settles down, so high pressure is recorded here. If you look at the pattern of pressure distribution over the surface of the planet, you will notice that belts of low and high pressure alternate.

In addition, you need to remember about the uneven heating of both hemispheres of the Earth throughout the year. This leads to some displacement of the low and high pressure belts. In summer they move to the north, and in winter - to the south.

How to drink water in the heat if you have hypertension

Hypertensive patients need water at any outside temperature. Often in the heat there is not enough of it, and then a person becomes ill. In order for water to be absorbed without swelling, you must follow the following drinking rules:

• Drink the bulk of the water in the morning and evening (before the heat sets in and after it goes away).
• The smaller part is during the day.
• To drink during hot weather, add a little salt to the water.
• After eating, you can’t drink water right away, you can drink it after half an hour.
• Avoid contrasts - do not drink water from the freezer. Sudden cooling causes constriction and spasm of blood vessels. Afterwards - their strong expansion. Such jumps and changes are undesirable for a hypertensive patient.

What else is important for a hypertensive patient in the heat?

• Avoid alcohol (taking poisons increases dehydration, takes away available water for detoxification, removal of poison).
• Avoid smoking (tobacco thickens the blood, slows down its flow, and increases blood pressure).
• Avoid heavy foods (fried, fatty, smoked, highly salted) - excess salt retains water and reduces heat transfer (sweating).
• In hot weather, replace traditional food with fresh juicy fruits (watermelons, melons). Replace hot dishes with cold ones.
• If possible, walk barefoot (to improve blood circulation and provide additional heat exchange - walking barefoot cools).

For a patient with hypertension, it is important that vacations in the south take place in climatic zones with little humidity. Then the risk of complications and the likelihood of crises will be minimized. Why is high humidity bad for hypertensive patients?

Atmospheric pressure normal for humans

Normal atmospheric pressure is 760 mmHg. Art. or 101,325 Pa at 0 ℃ at sea level (45° latitude). In this case, each square centimeter of the earth's surface is affected by the atmosphere with a force of 1.033 kg. A column of mercury 760 mm high balances the mass of this column of air.

Almost all of the Maldives, an island nation in the Indian Ocean, is located almost at sea level. This makes the Maldives the "lowest-lying" country in the world, under constant threat from rising sea levels. The country hopes to buy land in India, Sri Lanka or Australia to be able to evacuate residents of the Maldives if the islands begin to go under water.

The aforementioned Torricelli also noticed during the experiment that when the flask is filled with mercury, an unfilled space remains in its upper part - emptiness. Over time, this phenomenon began to be called “Torricelli void.” Then the scientist did not yet know that during his experiment he created a vacuum - that is, a space free of any substances.

At a standard pressure of 760 mmHg. Art. the person feels most comfortable. The air presses on a person with a force of about 16 tons, but we do not notice it. Why don't we feel this pressure?

The fact is that there is pressure inside our body too. Not only people, but also representatives of the animal world have adapted to atmospheric pressure. Each organ was formed and developed under the influence of this force. When the atmosphere acts on a body, this force is evenly distributed over the entire surface. Thus, our internal pressure is balanced with external pressure, and we do not feel it.

Normal atmospheric pressure should not be confused with climate norm. Each region has its own standards for a certain time of year. For example, in Vladivostok, the average annual atmospheric pressure is almost equal to the norm - 761 mm Hg. Art.

But in settlements located in mountainous areas (for example, in Tibet), the pressure is usually much lower - 413 mm Hg. Art. This is associated with an altitude of about 5000 m.

Panoramic view of the city of Puno next to Lake Titicaca, in the Peruvian Andes, near Bolivia. Puno is the capital of the province of Puno with a population of approximately 150,000 people. The city is located at an altitude of 3812 meters above sea level. Atmospheric pressure at this altitude is about 483 mmHg. Art.

What kind of nutrition is needed at altitude?

In the prevention of mountain sickness, a complete and balanced diet is of great importance: varied and satisfying, containing sufficient amounts of proteins, carbohydrates, fats, mineral salts and vitamins. It is recommended to eat hot food rather than dry food. During the entire ascent, there must be hot sweet tea. Alcoholic drinks should be completely excluded from the diet. The statement that alcohol speeds up blood flow and instills vigor is wrong. After drinking alcoholic beverages, temporary excitement occurs, which after some time is replaced by a loss of strength and loss of the ability to pay attention, which is very harmful in high altitude conditions.

At altitudes exceeding 5000 m, the amount of fluid consumed should be at least 4-5 liters per day. This helps eliminate toxins and avoids dehydration. You should also increase the calorie content of food to 5000 kcal per day. If possible, dishes should be “spicy” to increase the secretion of digestive juices. In the process of adaptation to high altitudes, the oxidation of fatty acids becomes more difficult. Because of this, ketones accumulate in the body - under-oxidized products of fat metabolism, which can cause symptoms of “altitude sickness” such as nausea and vomiting.

It is justified to include in the diet a 10% increase in the amount of carbohydrates in the form of sucrose and glucose, since they suppress the formation of ketones and thereby prevent the appearance of unpleasant symptoms of hypoxia. In the process of adaptation to altitude sickness, instant and easily digestible milk proteins are recommended, as well as protein products specially created for this purpose (protein chocolate, protein cookies), freeze-dried meat and fish products. To combat “altitude sickness,” Nepalese advise drinking yogurt, which partially restores the acid-base balance in tissues and improves well-being.

The influence of atmospheric pressure on humans

For a long time, medicine did not recognize the connection between weather events and health. Only over the past 50 years, thanks to a comprehensive study of the influence of weather conditions on the human body, it has been proven that atmospheric pressure and human health are closely related, and people react to any weather changes with complications in their well-being. The situation when weather conditions affect the physical state of the human body is called meteopathy.

Meteopaths are people whose body reacts to even minimal deviations of atmospheric pressure from the norm. They also include people with certain chronic diseases (in particular, cardiovascular, nervous system, etc.).

The atmospheric pressure fluctuates within 30 mm Hg per year. Art. During the day, values ​​can fluctuate from 1 to 3 mmHg. A healthy person does not feel these changes, but weather-dependent people with any health problems can feel these deviations.

Hypertension and hypotension are two main diseases characterized by meteorological dependence.

High atmospheric pressure is extremely unsafe for hypertensive patients and people with heart disease. Anyone who has hypertension and sensitivity to weather changes will have to deal with the following symptoms: the heart beats faster, against the background of which blood pressure (BP) rises; the skin begins to turn red; weakness is observed; There is noise in the ears, spots in front of the eyes, and pulsation in the head.

People with hypertension in old age feel strongly the weather changes. Their body is weakened by age-related changes and accumulated diseases, resulting in a risk of hypertensive crisis, damage to the heart and blood vessels.

A drop in atmospheric pressure primarily affects the health of people with hypotension and respiratory pathologies. The percentage of carbon dioxide in the air increases, and oxygen, on the contrary, decreases. Such changes in weather conditions due to a lack of oxygen in hypotensive patients cause ailments: blood circulation slows down and the pulse weakens, blood flows worse to the organs, blood pressure drops; breathing becomes difficult; drowsiness and fatigue, dizziness and nausea appear; intracranial pressure increases, against the background of this, spasms occur that turn into headaches.

The dependence of people’s well-being on atmospheric pressure concerns not only surges in blood pressure. In people with mental disorders, the manifestation of obsessive states, fears and various phobias increases.

With joint diseases, the likelihood of pain attacks increases at the sites of fractures and where problems exist.

Absolutely anyone, even a healthy person, will feel significant deviations from the norm. This applies to both high and low pressure.

The effect of low atmospheric pressure on the well-being of a person located, for example, in the mountains, is manifested in increased breathing and heart rate, headaches, asthma attacks and nosebleeds. Symptoms disappear as the person gets used to the surrounding conditions. There is often a need for medical care for people who have signs of oxygen deprivation.

Climbers, when climbing mountain peaks, are forced to take oxygen cylinders with them in order to avoid death from lack of oxygen.

Climbing Everest

With elevated blood pressure, a person's pulse slows down and respiratory function is inhibited. In addition, blood clotting increases and intestinal walls contract. The influence of external pressure on a person’s well-being increases in proportion to the distance to which the person descends. People who work at depth are most susceptible to the effects of high pressure. The amount of dissolved gases in the blood reaches its maximum value, performance and concentration increase. However, at the same time, a large amount of oxygen has a toxic effect and provokes the occurrence of lung diseases. Raising workers from depth is carried out in a special way in accordance with accepted techniques. If the rate of ascent is disrupted, gas bubbles clog the blood vessels and death can occur.

Continental climate: central Russia

It is better for hypertensive patients to spend the summer in a continental climate. At this time, warm, dry weather sets in here. The absence of high humidity and sudden temperature changes guarantees a comfortable feeling for hypertensive patients.

When choosing a city for summer residence, keep in mind: in the temperate zone, heat is possible, in the northern territories there will be no heat, you will only get pleasant summer warmth.

Warm south: Anapa or Sochi

Sochi is a popular climatic resort. It has a humid subtropical climate, with temperatures ranging from 0 to +30°C. Humidity is maintained at 70-80% throughout the year. Therefore, the best time for hypertensive patients to visit Sochi is the cool season (early spring, winter, autumn).

In summer, the subtropics become too humid. Against the backdrop of heat, patients with hypertension may experience crisis conditions. Therefore, you should not go to Sochi in June, July, August.

In summer you can visit the northern Black Sea coast - from Anapa to Tuapse. It has a semi-dry Mediterranean climate. It is characterized by a small amount of summer humidity and a high concentration of moisture in winter.

Therefore, a summer holiday in Anapa is something that hypertensive patients can do.

sea ​​coast

Also, due to high humidity, hypertensive patients feel unwell in many coastal cities. Hypertension often increases in Murmansk, Vladivostok, and St. Petersburg. And weakens after moving inland.

Therefore, if as you get older you feel the climate is not right, you will have to change your place of residence.

Crimea

The coast of the Crimean peninsula differs from Sochi and Adler in a drier climate. There are warm, dry summers and wet winters. Therefore, it is in Crimea that hypertensive patients feel comfortable throughout the summer months.

Is it possible for hypertensive patients to go south?

The southern climate is characterized by a significant rise in temperatures. How does heat affect the human body? What changes occur in the blood of a hypertensive patient at temperatures above +30°C?

Cyclones and anticyclones

There are two main types of pressure systems in the atmosphere: cyclones and anticyclones. Cyclones and anticyclones are wind systems that have opposite characteristics.

A cyclone is a collection of winds circulating in a low pressure system. It rotates counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere. It is usually associated with wet and stormy weather.

An anticyclone is a type of wind that circulates in a high pressure system. It rotates clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere. It is usually associated with dry and clear weather.

In order to better understand how these two phenomena differ, let's look at them in more detail.

A cyclone is an area of ​​low pressure where air masses rise. This usually indicates bad weather, such as rain or clouds. Winds in cyclones blow counterclockwise in the northern hemisphere and clockwise in the southern hemisphere. In a cyclone, air near the ground is forced toward the low-pressure center of the cyclone and then rises, expanding and cooling as it moves. As the rising air cools, it becomes more humid, leading to cloudiness and high humidity inside the cyclone. The main effects of tropical cyclones include heavy rain, strong winds, severe storm surges close to shore, and tornadoes. Destruction from a tropical cyclone, such as a hurricane or tropical storm, mainly depends on its intensity, size and location.

There are two types of cyclones:

1. Tropical cyclones . These cyclones that form over warm tropical oceans are also called tropical storms or tropical depressions. They are relatively small in size. However, they are characterized by enormous, destructive wind power.

The main tropical cyclone basins include the North Atlantic (including the Caribbean), the eastern Pacific, the western Pacific, the northern Indian Ocean, the southwestern Indian Ocean, the southern Pacific and the Australian region. Typically, tropical cyclones develop between 5 and 30 degrees latitude, as they require ocean water at a temperature of 27°C or so to form.

The terminology associated with tropical cyclones is quite confusing because people call these dangerous storms by different names in different parts of the world. In the North Atlantic and Caribbean, as well as the northeastern Pacific, they are commonly called "hurricanes." In the northwest Pacific, the most active tropical cyclone basin in the world, they are “typhoons,” while in the Indian Ocean and South Pacific they are simply “tropical cyclones” or “cyclones.” “Tornadoes”—much smaller and more localized than tropical cyclones, but capable of generating even higher wind speeds—are sometimes colloquially called “cyclones,” although they are completely different storms.

Particularly severe thunderstorms, which generate most of the world's most powerful tornadoes, form rotating updrafts called mesocyclones. In the United States, about 1,700 mesocyclones occur annually, with approximately 50 percent of them becoming tornadoes.

The birth of a huge tornado

Cyclones are among the most dangerous and destructive natural disasters that can occur. They have been responsible for 1.9 million deaths worldwide over the past two centuries. According to some estimates, up to 10,000 people die from these storms each year. Cyclones usually cause the greatest damage to coastal areas.

The consequences of Cyclone Idai - the deadliest tropical cyclone among the cyclones in the southwestern Indian Ocean that existed from March 4 to March 21, 2021. Wind gusts reached speeds of 280 km/h. The cyclone affected the states of Mozambique, Madagascar, Zimbabwe and Malawi, causing severe flooding in the affected areas, leading to numerous casualties. At least 1,297 people were killed, hundreds of thousands were left in need of assistance, and economic losses in these regions totaled more than $2 billion.

Consequences of tropical cyclone Kenneth in Mozambique. The cyclone hit northern Mozambique on April 25, 2021, with heavy rainfall and winds of up to 220 km/h. As a result of the disaster, more than 40 people died. In the Comoros Islands, the cyclone destroyed almost 80% of farms and more than 60% of crops, as well as over 3,800 houses. Previously, Mozambique was seriously affected by tropical cyclone Idai .

2. Extratropical or mid-latitude cyclones . They develop along frontal boundaries in mid-latitudes. These cyclones, which, unlike their tropical counterparts, develop where sharp temperature gradients exist between adjacent air masses, can be much larger than hurricanes, although their winds tend to be weaker. They reach several thousand kilometers in diameter.

3. Polar cyclones, also known as “Arctic hurricanes,” sometimes form over the Arctic and Antarctic seas, caused by the influence of cold air moving over slightly warmer ocean waters. In the Northern Hemisphere, meteorologists sometimes call polar cyclones “Arctic hurricanes” because their energy source is heat transfer from water to air and latent heat released by cloud condensation, and because their spiral cloud bands are somewhat similar to tropical cyclones. Polar cyclones often form quickly, sometimes in less than 24 hours, and are difficult to predict in advance.

An anticyclone is an area of ​​high pressure where air masses descend towards the ground. This usually indicates good weather. Winds in an anticyclone blow clockwise in the northern hemisphere and counterclockwise in the southern hemisphere. Air masses in the center of the anticyclone move downwards, being replaced by a downward flow of air from high altitudes. As it moves down, the air compresses and heats up, which reduces its humidity and leads to a decrease in the number of clouds inside the anticyclone, dry and cloudless weather.

As you know, winds blow from a high pressure system to a low pressure system. In the case of an anticyclone, the wind blows and diverges from the center of the high pressure system. However, it does not flow straight out. Due to the Earth's rotation, air tends to move in a spiral. In the Northern Hemisphere, air currents in areas of high pressure move clockwise, and in the Southern Hemisphere, they move counterclockwise. This pattern ensures that winds to the east of an anticyclone in the Northern Hemisphere will bring cold air from the north, while winds to the west will bring warm air from the south. In the Southern Hemisphere this picture is reversed.

An anticyclone brings stable weather conditions corresponding to the time of year. In summer the weather is windless and hot, in winter it is frosty. It is characterized by few or no clouds.

Anticyclones form in certain areas. For example, they are most often found over large bodies of ice: in Antarctica, Greenland and the Arctic. They also sometimes appear in the tropics.

Anticyclones also carry danger and unpleasant consequences. They can contribute to fires and prolonged drought. With a long absence of wind in large cities, harmful substances and gases accumulate, which is especially important for people with respiratory diseases.

Smog in China. In some cities, it is almost impossible to go outside without a mask. The smog is even visible from space. Scientists have calculated that walking the streets without a mask is equivalent to smoking a pack of cigarettes.

How does atmospheric pressure change with altitude?

Atmospheric pressure is directly related to altitude. The higher, the lower the pressure and vice versa. If you rise 12 m above sea level, the mercury column in the barometer will decrease by 1 mm.

Near the Earth's surface, pressure decreases with height at a rate of about 3.5 millibars for every 30 meters. However, in the case of cold air, the decrease in pressure can be much faster because its density is greater than that of warmer air.

At sea level, the atmospheric pressure is about 1000 mb (100 kPa). At the summit of Everest (8848 meters) the pressure drops to about 300 mb (30 kPa).

The pressure at an altitude of 270,000 meters is 10-6 mb, which is comparable to the pressure in the best vacuum ever artificially created by man. At altitudes between 1,500 and 3,000 meters the pressure is so low that it can cause altitude sickness and serious physiological problems if careful acclimatization is not undertaken.

Pressure is most often displayed in hectopascals (1 hPa = 102 Pa) rather than in millimeters of mercury: 1 mmHg. Art. = 133.3 Pa = 1.333 hPa. The relationship between height and pressure is easy to obtain using a simple formula:

∆h /∆P = 12 m/mm Hg. Art. or ∆h/∆P = 9 m/hPa,

where ∆h is the change in height,

∆P - change in pressure.

Thus, with an increase of 9 meters, the pressure level decreases by 1 hPa (100 Pa). This indicator is called the pressure level. Standard atmospheric pressure is 1013 hPa (can be rounded to 1000).

How to calculate the change in pressure at a different altitude using this data? For example, when rising 90 m, the pressure will decrease by 10 hPa. In this case, it turns out that when ascending 900 m, the pressure will drop to 0.

But, since air density also changes with altitude, when it comes to greater distances (starting from 1.5-2 km), all calculations must be carried out taking this parameter into account.

Height versus pressure graph

A graph of changes in atmospheric pressure with altitude clearly displays all of the above. It looks like a curved line rather than a straight line. Due to the fact that the density of the atmosphere is not the same, with increasing altitude the pressure begins to decrease more and more slowly. However, it will never reach zero, because there is a certain amount of particles of matter everywhere - there is no absolute vacuum in the Universe.

What are the signs of altitude sickness?

The main symptoms of mountain sickness include: increased heart rate, shortness of breath, headache, dizziness, rapid pulse, tinnitus, muscle weakness, cardiac dysfunction. As the tourist rises to altitude, his visual acuity decreases and the correctness of distance determination is impaired. Dry mountain air, loss of fluid due to increased ventilation of the lungs and sweating lead to dehydration of the body. Under normal conditions, a person loses about 3 liters of fluid, and when trekking in Nepal, moisture loss reaches 8-10 liters per day, depending on the altitude gained and the degree of physical activity.

Insufficient oxygen saturation of the blood leads to oxygen starvation of the brain cells most in need of oxygen, causing mental disorders. In addition, changes in the body's thermoregulation and a decrease in pain sensitivity are observed. In this regard, if you get mountain sickness, there is a risk of quickly getting frostbite or pneumonia.

Mountain sickness during mountain hiking and climbing can manifest itself both suddenly - with excessive overexertion in conditions of oxygen deficiency, and gradually. It can be recognized by the first signs - fatigue, drowsiness, dizziness, poor appetite. If the climb continues, the breathing rhythm is disrupted, nausea and vomiting occur, chills and fever appear. In addition, cyanosis develops - the pallor of the skin, especially the face, increases, and the lips turn blue. In the absence of proper acclimatization, headaches and drowsiness continue to increase. Shortness of breath is pronounced, there may be bleeding from the nose and lungs. A dry throat causes a cough and a constant desire to drink.

Mental disorders are not uncommon in high altitudes. With the development of mountain sickness, even slight mental stress causes severe headaches. The blood flow to the brain is disrupted, so attention and memory volume sharply decrease, and peculiar character changes are observed. For some, these changes are expressed in indifference, lethargy, weakness of will, and for others - in agitation. In severe cases, the period of excitement (euphoria) is replaced by a sharp depression of the psyche and subsequently turns into a general diffuse inhibition. Along with this, the mechanism of self-control changes and the risk of making inadequate or completely absurd decisions increases. At high altitudes, climbers may experience hallucinations. Because of this, they see some visions. They hear voices and start talking to themselves. In rare cases, loss of consciousness may occur. Sleep becomes restless, people have difficulty falling asleep and often wake up from suffocation.

Further ascent to altitude by participants with symptoms of altitude sickness can lead to the development of serious pathologies. Including focal lesions of the heart, liver, acute renal failure, acute pneumonia, developing into pulmonary edema, as well as hemorrhage in the brain (stroke) and cerebral edema.

Atmospheric pressure in the mountains

In the mountains, the atmospheric pressure will somehow be lower than at the edge of the sea. How a person will feel depends on the altitude and some additional conditions. For example, with normal humidity, climbing 3000 m can cause weakness and decreased performance. This occurs due to lack of oxygen.

In a humid climate, such sensations arise already at an altitude of 1000 m. The fact is that water molecules displace oxygen molecules - there is less oxygen in humid air. And in a dry climate you can climb 5000 m with almost no problems.

The temperature and pressure of the earth's atmosphere change with altitude. Temperatures, indicated by the yellow line, fall with altitude in some zones but rise in others. The pressure, indicated by the black line on the right, decreases greatly with altitude. Encyclopædia Britannica, Inc.

The influence of different altitudes on humans:

- 5 km - there is a lack of oxygen;

— 6 km is the highest altitude at which permanent human settlements exist;

— 8.9 km — the height of Everest. Water at this altitude boils at a temperature of + 68 ℃. Experienced, trained climbers may not be able to stay at this altitude for long;

- 13.5 km - you can only be safe here with a supply of pure oxygen. This is the maximum permissible height at which you can be without special equipment;

— 20 km is a height unacceptable for humans. It is safe only if you are in a hermetically sealed cabin.

A climber stands on the top of Mount Everest, Nepal. Mount Everest is so high that the amount of oxygen there is too low for breathing. Many climbers need oxygen tanks to reach the summit safely.

Atmospheric pressure today:

What human factors influence the development of altitude sickness?

Individual resistance of people to oxygen deficiency

While hiking in the Himalayas, you will notice that even in the highest mountains there are people constantly living. Having once settled in these areas, the highlanders at the genetic level developed resistance to hypoxia. For example, they have dark skin that is less sensitive to the burning rays of the sun. They have increased lung capacity. Thanks to the presence of a special EPAS1 gene, in residents of high mountains the level of red blood cells in their blood does not increase, and the blood remains liquid. Moreover, their body produces more nitric oxide, which allows the blood vessels not to narrow and maintain an increased blood flow rate. This physiology allows mountain dwellers to obtain more oxygen from rarefied air than inhabitants of the plains. In contrast, ordinary trekkers need time for their bodies to adapt to the mountain air.

In this regard, it is important to note that some people genetically do not have the ability to adapt to staying at an altitude of more than 2500 m. Their bodies do not have genes responsible for the synthesis of respiratory enzymes, without which oxygen cannot be transported to the brain. And even with effective external respiration, tissue respiration does not occur in the body. People who go hiking in the mountains for the first time and do not know their ability to adapt to altitude are considered a high-risk group. Due to impaired brain function, they can get serious complications in the body.

Gender and age

According to the observations of mountain guides, trekking at high altitudes is easier for women and older people. With a lack of oxygen, it is most difficult for people who are prone to pressure surges and young men of large build with bulky muscle mass. The history of climbing knows cases when trained athletes are forced to return to camp without completing the climb, and a fifty-year-old lean instructor safely brings the girls to the top.

Physical condition, level of training

Good physical fitness, and especially developed lungs, significantly increases resistance to stress at altitude, although it does not protect against the development of altitude sickness. The level of fitness will be much higher if, a few months before the start of trekking, you start doing fitness, doing multi-kilometer runs, running up the stairs of a multi-storey building, cross-country skiing in winter, and cycling in summer. At the same time, training and loads should be reasonable. You shouldn't exhaust yourself before going to the mountains.

High Altitude Experience

Upon returning from the mountains, acclimatization to altitude disappears as quickly as it appeared. The body does not need an excess of oxygen and begins to restore its previous mode of operation. This explains the poor health of climbers in the first days of life after descending from a great height. Reacclimatization will take about a week. During this time, hemoglobin will drop to normal levels, and your health will improve. Therefore, it is incorrect to say that the human body can remain resistant to hypoxia for a long time. In reality, we are talking about gaining high-altitude experience, which is not the same thing.

According to scientists, high-altitude experience has two components: subconscious and conscious. The subconscious component is the body’s memory of the order of triggering adaptive reactions and correct behavior in conditions of oxygen deficiency. Thanks to it, a person acclimatizes to altitude faster and more efficiently. The conscious component represents the knowledge acquired by a person about the reaction of his body to hypoxia. Knowing about the individual symptoms that precede an exacerbation of mountain sickness, a person acclimatizes more gently and does not allow overloads when climbing to altitude.