The concept of health in the aspect of adaptation theory

Currently, the problem of interaction of the human body with the environment does not lose its relevance. A complex set of external influences, including a wide range of anthropogenic influences, places high demands on the body. Preserving human health and preventing diseases is becoming not only a particular problem of medicine, but also of natural science in general, as well as one of the general humanitarian values.

Adaptation of the structure and functions of the body to conditions environment occurs during the adaptation process. According to the concept of G. Selye, adaptation is one of the fundamental qualities of living matter, which is often identified with the very concept of life. In the modern understanding, adaptation is the process of forming an optimal structural and functional correspondence, ensuring the most beneficial functioning of the body under certain conditions. In this case, the problem of interaction of the organism with the environment is considered within the framework of a systemic-functional approach, taking into account not only external connections, but also a set of changes within the organism, aimed at maintaining homeostasis.

In this regard, the main content of adaptation is the internal processes in systems that ensure the preservation of its external functions in relation to the environment. This goal is achieved through adaptive and compensatory reactions. Adaptive reactions consist in the fact that a system, responding to changes in environmental parameters that are essential for it, rearranges its structural connections to preserve the functions that ensure its existence as a whole. Compensatory reactions are aimed at preserving the function of the system even in the event of disruption of the functional element. Thus, compensatory reactions are carried out not by the element, but by the system in relation to the element.

The concept of adaptation is used in different aspects. There is genotypic adaptation - a process that forms the basis of evolution, in which, due to hereditary variability, mutations and natural selection, modern views animals and plants. A complex of species-specific hereditary characteristics underlies another type of adaptation acquired during individual development organism - phenotypic adaptation, which forms the individual appearance of the organism.

The concept of phenotypic adaptation was formulated by F. Z. Meerson. According to this theory, two stages can be traced in the development of most adaptive reactions: First stage- urgent, but imperfect adaptation and the subsequent stage - perfect, long-term adaptation.

An urgent adaptation reaction occurs immediately after the onset of the stimulus. Highest value in maintaining homeostasis in the early stages of adaptation, the body has compensatory reactions. Typical manifestations of the urgent stage of adaptation are reflex reactions that occur under the influence of hypoxia, cold, heat, etc. The most important feature of this stage is that the body’s activity proceeds at the limit of its physiological capabilities - with almost complete mobilization of functional reserves - and turns out to be insufficient . An important place in the initial period of adaptation is occupied by nonspecific mechanisms of increasing the body's resistance, i.e., the stress response.

Long-term adaptation develops gradually, as a result of repeated or prolonged action of environmental factors, based on the repeated implementation of urgent adaptation. The basis of long-term adaptation is made up of structural changes in organs and systems most involved in compensatory reactions of the urgent stage. Studies conducted on a variety of objects have clearly shown that an increase in the function of organs and systems naturally entails the activation of synthesis nucleic acids and proteins in the cells that form these organs and systems. This leads to a set of structural changes that fundamentally increase the power of systems responsible for adaptation, which forms the basis for the transition from the urgent stage of adaptation to the long-term one.

According to F. Z. Meyerson, the founder of the direction of “adaptive medicine,” phenotypic adaptation in humans is more important than in other animal species, since in humans this process is more meaningful and effective. In accordance with these ideas, R.P. Kaznacheev defined adaptation (adjustment) as the process of maintaining the functional state of homeostatic systems and the organism as a whole, ensuring its preservation, development, performance, and maximum life expectancy in inadequate environmental conditions. Are considered inadequate environmental conditions, not corresponding to this moment genophenotypic properties of the organism as a biosystem. The use of the body's adaptation to various environmental factors makes it possible to expand the zone of human existence and allows one to maintain health in unfavorable conditions.

Conditions for conducting research, monitoring the thermal state of subjects

Before the study, each subject was familiarized with the electromyographic study protocol and the nature of the temperature effect. The comparison group consisted of volunteer subjects who were practically healthy at the time of the study and had chronic diseases without exacerbation. The selection of subjects was carried out on the basis of medical history and a standard examination immediately before the electromyography session (measurement of temperature, blood pressure). The study of children was carried out with the consent of the parents in the presence of medical personnel. Subjects according to at will could stop participating in the study at any time.

Electroneuromyographic studies, analysis of evoked cutaneous vegetative potential (ESEP) and spirometric tests were carried out in the laboratory (air temperature +22 - 24C, humidity 50-60%; air speed less than 0.1 m/s) after the subject remained in the room for 30 minutes for stabilization skin temperature.

To control the thermal state of the subjects, central temperature (TC) was measured sublingually or rectally and weighted average skin temperature (WAT) according to N. L. Ramanathan. To do this, the rut temperature was measured at 4 points - under the collarbone (Ti), on the lateral surface of the middle of the shoulder (Tg), on the lateral surface of the middle of the thigh (Tz) and on the medial surface of the middle of the shin (T4). Further calculation of SVTC was carried out using the formula: SVTC = 0.3 (T, + T2) + 0.2 (T3 + T4), where the coefficient in front of the temperature values ​​means the approximate surface area of ​​these skin areas. SVTK was determined every 5 - 10 minutes. Figure 2.1 shows graphs for recording SVTK during electroneuromyographic studies in adult subjects. Central temperature was measured sublingually, since it quite accurately reflects its changes and is easy to measure. practical application.

In children aged from 7 days to 3 years, skin temperature was measured at only one point (on the thigh), since, firstly, it quite accurately reflects changes in the SVT and, secondly, the abundance of electrodes (electromyographic and temperature) caused significant emotional - motor restlessness of the child, which would inevitably affect the nature of the EMG.

To measure temperature, temperature sensors made on the basis of copper-constantan thermocouples were used. Changes in the electrical properties of the thermocouple were converted into digital values ​​using a 5-channel indicator.

The force of maximum voluntary contraction (MVC) of the biceps brachii muscle was determined as follows. The subject stood with his arm in elbow flexion (the shoulder is located along the chest, the joint angle is 90). The subject in this position had to exert maximum pressure on a dynamometer mounted on the lower surface of the stationary one. Dynamometry was performed before each EMG session.

MVC of the forearm muscles was determined by pressing with the hand on a dynamometer mounted on the lower surface of a stationary beam. In this case, the elbow joint was fixed in a splint to avoid involvement of the shoulder muscles.

Dosing of static force (isometric contraction) of the biceps brachii was created with loads weighing 4, 6, 8 and 10 kg, suspended on a cuff mounted on the forearm, 2 - 3 cm proximal to the wrist joint, for 3 - 5 s. In a standing position, the subjects were asked to hold their arm in a position of elbow flexion (the shoulder is located along the chest, the joint angle is 90).

Fatigue of m. biceps brachii was caused by dynamic loading to failure. The standing subject was required to perform flexion-extension movements of the elbow joint with a load of 30% of MVC until he was unable to perform full movements using only the arm muscles or until pain appeared.

Dosing of static force of the forearm muscles (t. flexor carpi radialis, t. flexor carpi radialis) was created with loads weighing 4, 6, 8 and 10 kg, suspended on a cuff mounted on the hand, for 3 - 5 s. In a sitting position, the subjects were asked to support the loaded hand at the same level as the forearm, with the arm in elbow flexion and the elbow joint fixed on the armrest. Fatigue of the forearm muscles was caused by movements in the wrist joint of the “flexion-extension” type with a load of 30% of MVC.

Functional indicators of the external respiratory system in individuals with different adaptations to the conditions of the European North

Parameters characterizing lung volumes and airway patency depending on gender and adaptation to the conditions of the European North are presented in Table 4.1. According to functional studies respiratory system, mild ventilation disturbances were documented in 9 people (30%).

The study of external respiration function revealed a tendency towards the formation of pulmonary ventilation disorders in migrants (see Table 4.1, Fig. 4.2, 4.3). Thus, VC (% of the proper value) in the group of men permanently residing in the North-West region of the Russian Federation (NW - m) was 96.96 ± 8.54, in the group of women permanently residing in the North-West region of the Russian Federation (NW - g), - 98.81 ± 16.27, in the group of men who arrived from other regions (South - m), -76.43 ± 13.98 (p 0.05 compared with SZ), in the group of women, those arriving from other regions (South - f), - 95.13±13.10 (p 0.05 compared with m); inspiratory volume (l) in the group NW - m was 3.60±0.35, NW - w - 2.60±0.34 (p 0.001 compared with m), South - m - 2.83±0.11 (p 0.001 compared to NW), South - f - 2.28±0.36 (p 0.05 compared to South - m).

Thus, analysis of lung volumes revealed restrictive ventilation disorders in migrant men.

Studies of forced expiratory parameters have revealed obstructive ventilation disorders, also more typical for male migrants. Thus, FVC (% of the proper value) in the NW - m group was 81.64 ± 14.89, NW - f - 84.05 ± 12.06, South - m - 71.43 ± 15.29, South - f - 67.20±9.72; FEV0.5 (l) in the group NW - m was 3.33±0.31, NW - f - 2.26±0.47 (p 0.001 compared with m), South - m - 2.58±0, 16 (p 0.01 compared with NW), South - f - 2.03±0.44 (p 0.05 compared with m); Tiffno's test, calculated as the ratio of FEV/FVC, in the group NW - m was 99.10±1.40, NW - f - 96.41±3.63, South - m - 96.47±3.29, South - w - 99.18±1.28; peak volumetric speed during exhalation (POS, % of the proper value) in the group NW - m was 110.19±6.60, NW - f - 90.14±25.85, South - m - 74.03±6.83 (p 0.01 compared to NW), South - f - 89.48±30.15; SOS25-75 (average volumetric expiratory flow rate, determined during exhalation from 25 to 75% FVC), characterizing the patency of small and medium bronchioles, in the SZ - m group was 131.71 ± 18.66, SZ - w - 109.43 ± 26.06, South-m - 88.73±9.00 (p 0.01 compared with NW), South-w - 110.30±26.18.

In persons with shortness of breath in the cold, a significant decrease in pulmonary ventilation was detected (Fig. 4.4). Thus, the inhalation volume was the smallest among migrants from the south in the presence of this symptom (p 0.001), in the same group the indicators characterizing the patency of the respiratory tract (FVC in % of the proper value, FEV.5 (l) and FEV] in % of the proper value values) were also lower compared to the values ​​for permanent residents of SZ and persons without shortness of breath (p 0.05).

With high sensitivity to cold in the form of enhanced cold-induced vasoconstriction (Raynaud's phenomenon), significant changes in pulmonary ventilation parameters were observed, which indicates the participation of microcirculation disorders in the pathogenesis of external respiration disorders. Correlation links showing the relationship between risk factors and parameters characterizing ventilation are shown in Figure 4.5.

Blood pressure and pulse indicators did not differ significantly between the studied groups and averaged: blood pressure - 113.41±3.01 mm Hg. Art., ADD - 67.00±1.96 mm. Hg Art., heart rate - 77.64±2.37 beats/min"1 (Table 4.2).

The level of adaptive capabilities, calculated on the basis of the IFI, in the studied group generally corresponded to the upper limit of normal values ​​(see Table 4.2). It was also noted that in the group of men the level of IFI was higher (p 0.05), which is on the border between satisfactory adaptation and stress of adaptation mechanisms. The integral characteristics of the functional capabilities of the cardiovascular system based on the PDP index in the studied groups generally corresponded to the values ​​not below satisfactory scores, with higher scores for men (Figure 4.6).

A correlation was established between IFI and PDP with the presence of increased cold-induced vasoconstriction in the subjects (p 0.05). Individuals with signs of increased cold-induced vasoconstriction demonstrated IFI and PDP, corresponding to the tension of adaptation mechanisms. Thus, in the group with this symptom, the IFI was 2.12±0.07 (p 0.05 compared to the group without enhanced cold-induced vasoconstriction 1.86±0.09); PDP in the group with this symptom was 94.41±4.37 (p 0.05 compared to the group without enhanced cold-induced vasoconstriction 79.85±5.68). The highest IFI rates were observed in men in the presence of enhanced cold-induced vasoconstriction (2.21±0.09, p 0.05).

Assessment of neuromuscular status using turn-amplitude analysis of iEMG

Determination of neuromuscular status based on the analysis of turn-amplitude EMG parameters was carried out in patients with diphtheria lesions of the peripheral nervous system. Diagnosis of diphtheria lesions of the nervous system was based on data established by a clinical study of patients, the results of bacteriological and serological methods, as well as the results of additional methods that made it possible to clarify the severity and localization of lesions of the nervous system. Research carried out jointly with A. M. Sergeev

Electroneuromyography (ENMG) was performed in 17 patients (6 m, 11 f) aged from 18 to 61 years ( average age 35.9±3.3 years) 1 - 18 months after diphtheria infection, accompanied by the development of polyneuropathy.

The diagnosis of diphtheria in 15 cases was confirmed bacteriologically during the acute period of the disease, and in 2 patients it was made retrospectively based on anamnesis, characteristic clinical picture, and unfavorable epidemiological situation. In the examined group of patients, symptoms of generalized sensory-motor polyneuropathy appeared 9 to 45 days (on average 26±3 days) from the onset of the main infectious disease; in 6 people the disease occurred in the form of polyradiculoneuropathy of the Guillain-Barré syndrome type.

At the time of the study, based on clinical assessment of the function of the peripheral nervous system, patients were divided into 2 groups. The first group included 6 patients (2 men, 4 women) aged 18 - 46 years, examined 10 - 18 months after diphtheria. In this group of patients, no motor function disorders were found during clinical examination. However, sensitivity disorders of the distal type were identified. We included 11 patients (4 men, 7 women) aged 30–56 years into the second group, who were examined 4–9 months after the onset of the main infectious disease. At the time of examination, these patients showed signs of impaired motor function in the form of moderately severe flaccid tetraparesis (n=6) or minimal muscle weakness in the distal parts of the limbs, mainly in the flexors of the hand (n=5). This corresponds to degrees I-II of motor deficit on the North American scale.

The control group consisted of 7 neurologically healthy volunteer subjects (4 m, 3 f) aged from 18 to 39 years (average age 28.5±2.4 years). Characteristics of the electroneuromyogram in healthy subjects The velocity of propagation of excitation (SPT) along the motor fibers of the ulnar nerve in healthy subjects was 60 - 70 m/s (on average 66.42±2.87 m/s).

In healthy subjects, 41 motor unit potentials (MUPs) of the triceps brachii were recorded using cutaneous electrodes. MUDEs in healthy individuals were characterized by a duration of 24–30 ms, an amplitude not exceeding 250 μV (mostly 90–150 μV), and a number of phases, usually less than 3x. The number of pseudopolyphasic PDEs was less than 10%. The average characteristics of the PDE are presented in Table 6.1.

A study of the characteristics of interference IEMG in healthy subjects revealed a natural increase in the amplitude (RMS) and number of “turns” (turns) of the EMG of the t. flexor carpi radialis as the load increases (Table 6.2).

In a two-dimensional coordinate system, where the abscissa axis reflects the values ​​of the applied load in kg, and the ordinate axis reflects the corresponding values ​​of the EMG parameters, the dependence of the IEMG parameters of the t. flexor carpi radialis on the load was expressed by linear equations.

Regression coefficients, reflecting the increase in EMG parameters and showing the slopes of the graphs to the x-axis, practically did not differ between individual subjects. The values ​​of the regression coefficients were in the range of 12.9-15.5 for the IEMG amplitude, for the number of EMG turns they were 12.0-14.5 (Table 6.3, Fig. 6.1). Noteworthy is the almost fourfold increase in both amplitude characteristics(RMS, Fig. 6.1, A), and the number of turns (Fig. 6.1, B) when the load increases from 2 to 8 kg.

Analysis of the IEMG parameters without taking into account the load by studying the ratio of the number of EMG turns to the average EMG amplitude for 1 s (Willison’s method) revealed that the maximum value of this ratio for the so-called flexor carpi radialis is observed in the amplitude range from 200 to 260 μV, for the so-called. gastrocnemius - from 190 to 240 µV, averaging 0.4 - 0.5 and 0.6 - 0.7, respectively (Table 6.4, Fig. 6.2).

Terentyeva Nadezhda Nikolaevna

I’ll tell you about one of the most incredible, from the point of view of everyday ideas, practices - the practice of free adaptation to the cold.

According to generally accepted beliefs, a person cannot be in the cold without warm clothing. The cold is absolutely destructive, and if by the will of fate you go outside without a jacket, the unfortunate person will face painful freezing and an inevitable bouquet of illnesses upon return.

In other words, generally accepted ideas completely deny a person the ability to adapt to cold. The comfort range is considered to be located exclusively above room temperature.

It seems like you can't argue with that. You can’t spend the whole winter in Russia wearing shorts and a T-shirt...

The fact of the matter is that it is possible!!

No, not by gritting my teeth and growing icicles to set a ridiculous record. And free. Feeling, on average, even more comfortable than those around me. This is real practical experience that shatteringly breaks generally accepted patterns.

It would seem, why own such practices? Yes, everything is very simple. New horizons always make life more interesting. By removing instilled fears, you become freer.
The range of comfort expands enormously. When everyone else is either hot or cold, you feel good everywhere. Phobias disappear completely. Instead of the fear of getting sick by not dressing warmly enough, you gain complete freedom and confidence in your abilities. It's really nice to run in the cold. If you go beyond the limits of your strength, then this does not entail any consequences.

How is this even possible? Everything is very simple. We are much better built than is commonly believed. And we have mechanisms that allow us to be free in the cold.

Firstly, when temperature fluctuates within certain limits, the metabolic rate, properties of the skin, etc. change. To avoid dissipating heat, the outer contour of the body greatly reduces the temperature, while the core temperature remains very stable. (Yes, cold paws are normal!! No matter how much we were told as children, this is not a sign of freezing!)

With even greater cold load, specific thermogenesis mechanisms are activated. We know about contractile thermogenesis, in other words, trembling. The mechanism is essentially an emergency one. Shivering warms you up, but it doesn’t come on because of a good life, but when you’re really cold.

But there is also non-contractile thermogenesis, which produces heat through the direct oxidation of nutrients in the mitochondria directly into heat. Among people who practice cold practices, this mechanism is simply called a “stove.” When the “stove” is turned on, heat is gradually produced in the background in an amount sufficient for a long stay in the cold without clothing.

Subjectively, this feels quite unusual. In Russian, the word “cold” refers to two fundamentally different sensations: “it’s cold on the street” and “it’s cold for you.” They can be present independently. You can freeze in a fairly warm room. Or you can feel the burning cold outside on your skin, but not freeze at all and not experience discomfort. Moreover, it's nice.

How can one learn to use these mechanisms? I will say emphatically that I consider “learning by article” risky. The technology needs to be handed over personally.

Non-contractile thermogenesis starts in fairly severe frost. And turning it on is quite inertial. The “stove” starts working no earlier than after a few minutes. Therefore, paradoxically, learning to walk freely in the cold is much easier in severe frost than on a cool autumn day.

As soon as you go out into the cold, you begin to feel the cold. At the same time, an inexperienced person is seized with panic horror. It seems to him that if it’s already cold now, then in ten minutes it will be a full paragraph. Many simply do not wait for the “reactor” to reach operating mode.

When the “stove” does start, it becomes clear that, contrary to expectations, it is quite comfortable to be in the cold. This experience is useful in that it immediately breaks the patterns instilled in childhood about the impossibility of such things, and helps to look differently at reality as a whole.

For the first time, you need to go out into the cold under the guidance of a person who already knows how to do this, or where you can return to the warmth at any time!

And you need to go out completely undressed. Shorts, better even without a T-shirt and nothing else. The body needs to be properly frightened so that it turns on forgotten adaptation systems. If you get scared and put on a sweater, trowel, or something similar, then the heat loss will be sufficient to freeze very much, but the “reactor” will not start!

For the same reason, gradual “hardening” is dangerous. A decrease in air or bath temperature “by one degree every ten days” leads to the fact that sooner or later a moment comes when it is already cold enough to get sick, but not enough to trigger thermogenesis. Truly, such hardening can only be withstood iron men. But almost everyone can go straight out into the cold or dive into an ice hole.

After what has been said, you can already guess that adaptation not to frost, but to low above-zero temperatures is a more difficult task than jogging in the cold, and it requires more preparation. The “stove” at +10 does not turn on at all, and only non-specific mechanisms work.

It should be remembered that severe discomfort cannot be tolerated. When everything works out correctly, no hypothermia develops. If you start to get very cold, then you need to stop the practice. Periodic going beyond the limits of comfort is inevitable (otherwise you won’t be able to push these limits), but extreme sports should not be allowed to escalate into kick-ass.

Over time, the heating system gets tired of working under load. The limits of endurance are quite far. But they exist. You can walk freely at -10 all day, and at -20 for a couple of hours. But you won’t be able to go skiing in just a T-shirt. (Field conditions are a completely separate issue. In winter, you can’t skimp on the clothes you take with you on a hike! You can put them in a backpack, but you can’t forget them at home. In snowless times, you can risk leaving extra things at home that you take only out of fear of weather. But, with experience)

For greater comfort, it is better to walk like this at more or less clean air, away from sources of smoke and from smog - sensitivity to what we breathe in this state increases significantly. It is clear that the practice is generally incompatible with smoking and booze.

Being in the cold can cause cold euphoria. The feeling is pleasant, but requires extreme self-control to avoid loss of adequacy. This is one of the reasons why it is very undesirable to start practicing without a teacher.

Another important nuance is the long reboot of the heating system after significant loads. Having properly caught the cold, you can feel quite good, but when you enter a warm room, the “stove” turns off, and the body begins to warm up with trembling. If you go out into the cold again, the “stove” will not turn on, and you can freeze very much.

Finally, you need to understand that mastering the practice does not guarantee not to freeze anywhere and never. The condition varies and is influenced by many factors. But the likelihood of getting into trouble from the weather is still reduced. Just as the likelihood of being physically deflated is much lower for an athlete than for a wimp.

Unfortunately, it was not possible to create a complete article. I'm just in general outline outlined this practice (more precisely, a set of practices, because diving into an ice hole, jogging in a T-shirt in the cold and wandering through the forest in the style of Mowgli are different). I'll sum it up with where I started. Possession own resources allows you to get rid of fears and feel much more comfortable. And this is interesting.

Dmitry Kulikov

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Ministry of Sports and Tourism of the Republic of Belarus

Educational institution

"Belorussian State University physical culture"

Institute of Tourism

Department of Technologies in the Tourism Industry

Controll work

in the discipline "Physiology"

onthoseat" Adaptation to low temperature"

Completed by: 2nd year student of group 421

correspondence form of education

Faculty of Tourism and Hospitality

Tsinyavskaya Anastasia Viktorovna

Checked by: Bobr Vladimir Matveevich

• Introduction
• 1. Adaptation to low temperature
• 1.1 Physiological responses to exercise in low ambient temperatures
• 1.2 Metabolic reactions
• Conclusion
• List of used literature

Introduction

The human body is affected by climatic factors such as temperature. Temperature is one of the important abiotic factors affecting the physiological functions of all living organisms. Temperature depends on latitude, altitude, and time of year.

When temperature factors change, then human body produces specific adaptation reactions for each factor. That is, it adapts.

Adaptation is a process of adaptation that is formed during a person’s life. Thanks to adaptation processes, a person adapts to unusual conditions or a new level of activity, i.e. the body's resistance to action increases various factors. The human body can adapt to high and low temperatures, low atmospheric pressure, or even some pathogenic factors.

People living in northern or southern latitudes, in the mountains or on the plain, in the humid tropics or in the desert differ from each other in many indicators of homeostasis. Therefore, a number of norm indicators for individual regions globe may vary.

1. Adaptation to low temperature

Adaptation to cold is the most difficult type of human climatic adaptation, achievable and quickly lost without special training. This is explained by the fact that, according to modern scientific ideas, our ancestors lived in a warm climate and were much more adapted to protect themselves from overheating. The onset of cooling was relatively rapid and humans, as a species, “did not have time” to adapt to this climate change in most of the planet. In addition, people began to adapt to low temperature conditions, mainly due to social and man-made factors - home, hearth, clothing. However, in extreme conditions human activity(including in mountaineering practice) the physiological mechanisms of thermoregulation - its “chemical” and “physical” sides become vitally important.

The body's first reaction to exposure to cold is to reduce skin and respiratory (breathing) heat loss due to constriction of blood vessels in the skin and pulmonary alveoli, as well as by reducing pulmonary ventilation (decreased depth and frequency of breathing). Due to changes in the lumen of skin vessels, blood flow in it can vary within very wide limits - from 20 ml to 3 liters per minute throughout the entire mass of the skin.

Constriction of blood vessels leads to a decrease in skin temperature, but when this temperature reaches 6°C and there is a threat of cold injury, the reverse mechanism develops - reactive hyperemia of the skin. With severe cooling, persistent narrowing of blood vessels may occur in the form of spasm. In this case, a signal of trouble appears - pain.

A decrease in the temperature of the skin of the hands to 27 °C is associated with a feeling of “cold”; at a temperature less than 20 °C - “very cold”; at a temperature less than 15 °C - “unbearably cold”.

When exposed to cold, vasoconstrictor (vasoconstrictor) reactions occur not only in cooled areas of the skin, but also in remote areas of the body, including internal organs(“reflected reaction”). Reflected reactions during cooling of the feet are especially pronounced - reactions of the nasal mucosa, respiratory organs, and internal genital organs. Constriction of blood vessels causes a decrease in the temperature of the corresponding areas of the body and internal organs with the activation of microbial flora. It is this mechanism that underlies the so-called “colds” with the development of inflammation in the respiratory system (pneumonia, bronchitis), urination (pyelitis, nephritis), genital area (adnexitis, prostatitis), etc.

The mechanisms of physical thermoregulation are the first to be included in the defense of constancy internal environment when the balance of heat production and heat transfer is disturbed. If these reactions are not enough to maintain homeostasis, “chemical” mechanisms are activated - muscle tone increases, muscle tremors appear, which leads to increased oxygen consumption and increased heat production. At the same time, the work of the heart increases, blood pressure and the speed of blood flow in the muscles increase. It is calculated that to maintain the heat balance of a naked person in still cold air, it is necessary to increase heat production by 2 times for every 10° decrease in air temperature, and with significant wind, heat production should double for every 5° decrease in air temperature. In a warmly dressed person, doubling the exchange rate will compensate for a decrease in external temperature by 25°.

With repeated contacts with cold, local and general, a person develops protective mechanisms aimed at preventing the adverse consequences of cold exposure. In the process of acclimatization to cold, resistance to frostbite increases (the frequency of frostbite in individuals acclimatized to cold is 6-7 times lower than in non-acclimatized individuals). In this case, first of all, the improvement of vasomotor mechanisms (“physical” thermoregulation) occurs. In persons exposed to cold for a long time, increased activity of “chemical” thermoregulation processes is determined - basal metabolism; they are increased by 10 - 15%. Among the indigenous inhabitants of the North (for example, Eskimos), this excess reaches 15 - 30% and is genetically fixed.

As a rule, due to the improvement of thermoregulation mechanisms in the process of acclimatization to cold, the share of participation of skeletal muscles in maintaining heat balance decreases - the intensity and duration of muscle shivering cycles becomes less pronounced. Calculations have shown that, due to physiological mechanisms of adaptation to cold, a naked person is able to tolerate air temperatures of at least 2°C for a long time. Apparently, this air temperature is the limit of the body’s compensatory capabilities to maintain heat balance at a stable level.

The conditions under which the human body adapts to cold can be different (for example, working in unheated rooms, refrigeration units, outdoors in winter). Moreover, the effect of cold is not constant, but alternates with the temperature regime normal for the human body. Adaptation in such conditions is not clearly expressed. In the first days, in response to low temperatures, heat generation increases uneconomically; heat transfer is not yet sufficiently limited. After adaptation, heat generation processes become more intense, and heat transfer decreases.

Otherwise, adaptation to living conditions in northern latitudes occurs, where a person is affected not only by low temperatures, but also by the lighting regime and level of solar radiation characteristic of these latitudes.

What happens in the human body during cooling?

Due to irritation of cold receptors, reflex reactions that regulate heat conservation change: the blood vessels of the skin narrow, which reduces the body’s heat transfer by a third. It is important that the processes of heat generation and heat transfer are balanced. The predominance of heat transfer over heat generation leads to a decrease in body temperature and disruption of body functions. At a body temperature of 35 °C, mental disorders are observed. A further decrease in temperature slows down blood circulation and metabolism, and at temperatures below 25 °C breathing stops.

One of the factors in the intensification of energy processes is lipid metabolism. For example, polar explorers, whose metabolism slows down in low air temperatures, take into account the need to compensate for energy costs. Their diets are characterized by high energy value (calorie content).

Residents of northern regions have a more intense metabolism. The bulk of their diet consists of proteins and fats. Therefore, the content of fatty acids in their blood is increased, and the sugar level is slightly decreased.

People adapting to the humid, cold climate and oxygen deficiency of the North also have increased gas exchange, high cholesterol levels in the blood serum and mineralization of skeletal bones, and a thicker layer of subcutaneous fat (which acts as a heat insulator).

However, not all people are equally capable of adaptation. In particular, in some people in the North, protective mechanisms and adaptive restructuring of the body can cause disadaptation - a whole series of pathological changes called “polar disease”.

One of the most important factors, ensuring human adaptation to the conditions of the Far North, is the body’s need for ascorbic acid (vitamin C), which increases the body’s resistance to various types of infections.

The insulating shell of our body includes the surface of the skin with subcutaneous fat, as well as the muscles located underneath it. When skin temperature drops below normal levels, constriction of skin blood vessels and contraction of skeletal muscles increase the insulating properties of the skin. It has been established that vasoconstriction of the passive muscle provides up to 85% of the total insulating capacity of the body under conditions of extremely low temperatures. This value of resistance to heat loss is 3-4 times higher than the insulating abilities of fat and skin.

1.1 Physiological responses to exercise in low ambient temperatures

metabolic temperature adaptation

As the muscle cools, it becomes weaker. Nervous system responds to muscle cooling by changing the structure of muscle fiber involvement. According to some experts, this change in fiber selection leads to a decrease in the efficiency of muscle contractions. At lower temperatures, both the speed and force of muscle contraction decreases. Trying to perform work at a muscle temperature of 25°C with the same speed and productivity as it was performed when the muscle temperature was 35°C will lead to rapid fatigue. Therefore, you have to either expend more energy or perform physical activity at a slower speed.

If clothing and exercise-induced metabolism are sufficient to maintain body temperature in cold environments, muscle activity levels will not decrease. However, as fatigue appears and muscle activity slows down, heat generation will gradually decrease.

1.2 Metabolic reactions

Prolonged physical activity leads to increased utilization and oxidation of free fatty acids. Increased lipid metabolism is mainly due to the release of catecholamines (epinephrine and norepinephrine) into the vascular system. Under conditions of reduced ambient temperature, the secretion of these catecholamines increases markedly, while the levels of free fatty acids increase significantly less compared with those during prolonged exercise under conditions of higher ambient temperature. Low ambient temperatures cause constriction of blood vessels in the skin and subcutaneous tissues. As you know, subcutaneous tissue is the main storage site for lipids (adipose tissue), so vasoconstriction leads to limited blood supply to the areas. From which free fatty acids are mobilized, as a result of which free fatty acid levels do not increase as significantly.

Blood glucose plays an important role in the development of tolerance to low temperature conditions, as well as maintaining the level of endurance during physical exercise. loads. Hypoglycemia (low blood glucose), for example, suppresses shivering and leads to a significant decrease in rectal temperature.

Many people are interested in whether the airways are damaged by rapid, deep inhalation of cold air. Cold air, passing through the mouth and trachea, quickly warms up, even if its temperature is below -25°C. Even at this temperature, the air, having passed about 5 cm along the nasal passage, warms up to 15°C. Very cold air entering the nose warms up sufficiently as it approaches the exit of the nasal passage; thus, there is no danger of injury to the throat, trachea or lungs.

Conclusion

The conditions under which the body must adapt to cold may vary. One of the possible options for such conditions is working in cold shops. In this case, the cold acts intermittently. In connection with the accelerated pace of development of the Far North, the issue of adapting the human body to life in northern latitudes, where it is exposed not only to low temperatures, but also to changes in light conditions and radiation levels, is currently becoming relevant.

Adaptation mechanisms make it possible to compensate for changes in environmental factors only within certain limits and for a certain time. As a result of exposure to factors that exceed the capabilities of adaptation mechanisms, maladaptation develops. It leads to dysfunction of body systems. Consequently, there is a transition of the adaptive reaction into a pathological one - a disease. An example of diseases of maladaptation are cardiovascular diseases among non-indigenous residents of the North.

List of used literature

1. Azhaev A.N., Berzin I.A., Deeva S.A., “Physiological and hygienic aspects of low temperatures on the human body,” 2008

2. http://bibliofond.ru/view.aspx?id=459098#1

3. http://fiziologija.vse-zabolevaniya.ru/fiziologija-processov-adaptacii/ponjatie-adaptacii.html

4. http://human-physiology.ru/adaptaciya-ee-vidy-i-periody

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I’ll tell you about one of the most incredible, from the point of view of everyday ideas, practices - the practice of free adaptation to the cold.

According to generally accepted beliefs, a person cannot be in the cold without warm clothing. The cold is absolutely destructive, and if by the will of fate you go outside without a jacket, the unfortunate person will face painful freezing and an inevitable bouquet of illnesses upon return.

In other words, generally accepted ideas completely deny a person the ability to adapt to cold. The comfort range is considered to be located exclusively above room temperature.

It seems like you can't argue with that. You can’t spend the whole winter in Russia wearing shorts and a T-shirt...

The fact of the matter is that it is possible!!

No, not by gritting my teeth and growing icicles to set a ridiculous record. And free. Feeling, on average, even more comfortable than those around me. This is real practical experience that shatteringly breaks generally accepted patterns.

It would seem, why own such practices? Yes, everything is very simple. New horizons always make life more interesting. By removing instilled fears, you become freer.
The range of comfort expands enormously. When everyone else is either hot or cold, you feel good everywhere. Phobias disappear completely. Instead of the fear of getting sick by not dressing warmly enough, you gain complete freedom and confidence in your abilities. It's really nice to run in the cold. If you go beyond the limits of your strength, then this does not entail any consequences.

How is this even possible? Everything is very simple. We are much better built than is commonly believed. And we have mechanisms that allow us to be free in the cold.

Firstly, when temperature fluctuates within certain limits, the metabolic rate, properties of the skin, etc. change. To avoid dissipating heat, the outer contour of the body greatly reduces the temperature, while the core temperature remains very stable. (Yes, cold paws are normal!! No matter how much we were told as children, this is not a sign of freezing!)

With even greater cold load, specific thermogenesis mechanisms are activated. We know about contractile thermogenesis, in other words, trembling. The mechanism is essentially an emergency one. Shivering warms you up, but it doesn’t come on because of a good life, but when you’re really cold.

But there is also non-contractile thermogenesis, which produces heat through the direct oxidation of nutrients in the mitochondria directly into heat. Among people who practice cold practices, this mechanism is simply called a “stove.” When the “stove” is turned on, heat is gradually produced in the background in an amount sufficient for a long stay in the cold without clothing.

Subjectively, this feels quite unusual. In Russian, the word “cold” refers to two fundamentally different sensations: “it’s cold on the street” and “it’s cold for you.” They can be present independently. You can freeze in a fairly warm room. Or you can feel the burning cold outside on your skin, but not freeze at all and not experience discomfort. Moreover, it's nice.

How can one learn to use these mechanisms? I will say emphatically that I consider “learning by article” risky. The technology needs to be handed over personally.

Non-contractile thermogenesis starts in fairly severe frost. And turning it on is quite inertial. The “stove” starts working no earlier than after a few minutes. Therefore, paradoxically, learning to walk freely in the cold is much easier in severe frost than on a cool autumn day.

As soon as you go out into the cold, you begin to feel the cold. At the same time, an inexperienced person is seized with panic horror. It seems to him that if it’s already cold now, then in ten minutes it will be a full paragraph. Many simply do not wait for the “reactor” to reach operating mode.

When the “stove” does start, it becomes clear that, contrary to expectations, it is quite comfortable to be in the cold. This experience is useful in that it immediately breaks the patterns instilled in childhood about the impossibility of such things, and helps to look differently at reality as a whole.

For the first time, you need to go out into the cold under the guidance of a person who already knows how to do this, or where you can return to the warmth at any time!

And you need to go out completely undressed. Shorts, better even without a T-shirt and nothing else. The body needs to be properly frightened so that it turns on forgotten adaptation systems. If you get scared and put on a sweater, trowel, or something similar, then the heat loss will be sufficient to freeze very much, but the “reactor” will not start!

For the same reason, gradual “hardening” is dangerous. A decrease in air or bath temperature “by one degree every ten days” leads to the fact that sooner or later a moment comes when it is already cold enough to get sick, but not enough to trigger thermogenesis. Truly, only iron men can withstand such hardening. But almost everyone can go straight out into the cold or dive into an ice hole.

After what has been said, you can already guess that adaptation not to frost, but to low above-zero temperatures is a more difficult task than jogging in the cold, and it requires more preparation. The “stove” at +10 does not turn on at all, and only non-specific mechanisms work.

It should be remembered that severe discomfort cannot be tolerated. When everything works out correctly, no hypothermia develops. If you start to get very cold, then you need to stop the practice. Periodic going beyond the limits of comfort is inevitable (otherwise you won’t be able to push these limits), but extreme sports should not be allowed to escalate into kick-ass.

Over time, the heating system gets tired of working under load. The limits of endurance are quite far. But they exist. You can walk freely at -10 all day, and at -20 for a couple of hours. But you won’t be able to go skiing in just a T-shirt. (Field conditions are a completely separate issue. In winter, you can’t skimp on the clothes you take with you on a hike! You can put them in a backpack, but you can’t forget them at home. In snowless times, you can risk leaving extra things at home that you take only out of fear of weather. But, with experience)

For greater comfort, it is better to walk in more or less clean air, away from sources of smoke and smog - sensitivity to what we breathe in this state increases significantly. It is clear that the practice is generally incompatible with smoking and booze.

Being in the cold can cause cold euphoria. The feeling is pleasant, but requires extreme self-control to avoid loss of adequacy. This is one of the reasons why it is very undesirable to start practicing without a teacher.

Another important nuance is the long reboot of the heating system after significant loads. Having properly caught the cold, you can feel quite good, but when you enter a warm room, the “stove” turns off, and the body begins to warm up with trembling. If you go out into the cold again, the “stove” will not turn on, and you can freeze very much.

Finally, you need to understand that mastering the practice does not guarantee not to freeze anywhere and never. The condition varies and is influenced by many factors. But the likelihood of getting into trouble from the weather is still reduced. Just as the likelihood of being physically deflated is much lower for an athlete than for a wimp.

Unfortunately, it was not possible to create a complete article. I have only outlined this practice (more precisely, a set of practices, because diving into an ice hole, jogging in a T-shirt in the cold and wandering through the forest in the style of Mowgli are different). I'll sum it up with where I started. Owning your own resources allows you to get rid of fears and feel much more comfortable. And this is interesting.

Like any creature, the horse is able to adapt to the cold to some extent. Question: How harmless will such an adaptation be for the horse’s health? What temperature can be considered critical? Are we confident that all horses react to cold in the same way?

Even if we talk about a healthy horse, which is almost impossible after its participation in sports or riding of any kind, is it as good in the cold, in the rain and snow as horse users of all faiths, from athletes to naturists, believe?

Thanks to “sports” veterinarians, we have a huge amount of research on the effect of heat and overheating on a horse - this is understandable: runs, races... And too little serious work on the effect of cold on the body. Such studies can be counted on one hand.

Trotters have found out that at temperatures below -23 °C, trotters die on the tracks... From the cold air.

And when training in cold temperatures of -22 °C, they remain alive! From which it is concluded that at -22 °C it is necessary to go out on the track, but in a blanket...

For several years, the Finns have been studying in detail how Finnish horses freeze, measuring the thickness of subcutaneous fat and hair length - and finally found out that they freeze very much. Conclusion: you need to wear blankets.

That's probably all the research...

Of course, any attempts to study the issue of the effect of cold on the body will be incomplete until we know what the horse itself thinks about this.

In the meantime, we are not sure what the horse actually feels in winter, we are forced to be guided by strictly scientific data of anatomy and physiology and, of course, our own guesses and common sense. After all, our task is to make any weather in our not very gentle climate as comfortable as possible for horses.

A comfortable temperature for a horse is considered to be from +24 to +5°C (in the absence of other irritating factors, of course). At this temperature, the horse does not need to expend additional energy on heating, provided that it is healthy and in good condition and in decent conditions.

Obviously, in any case, at temperatures below -G the horse will need additional sources of heat, and often, given humidity, windiness, etc., such a need may arise even in the range of “comfortable” temperatures.

What is physiological reaction body to the cold?

Immediate reaction. Occurs in response to a sudden sharp change in air temperature. The horse becomes noticeably cold, its fur stands on end (piloerection), blood flows from the limbs to the internal organs - the legs, ears, and nose become cold. The horse stands with its tail between its legs, without moving in order to save energy.

Adaptation. This is the next reaction of a horse exposed to further constant exposure to cold. It usually takes 10 to 21 days for a horse to acclimate to the cold to some extent. For example, a horse kept at a temperature of +20°C suddenly finds itself in conditions with a temperature of +5°C. It adapts to new environmental conditions in 21 days. If the temperature further decreases from +5 to -5°C, the horse will need up to 21 more days to adapt. And so on until the temperature reaches the lower critical level (LCL) of -15°C for an adult horse or 0°C for a growing one. Upon reaching critical temperature the horse’s body will begin to work in “emergency mode”, not to live, but to survive, which will lead to a serious and, sometimes, irreversible depletion of its resources.

As soon as NCO is achieved, stressful physiological changes begin, and the horse, in order to cope with the cold, needs human intervention: heating, additional nutrition.

It is clear that all data is conditional and differs for each specific horse. However, science currently does not have accurate data.

Physiological changes consist in the “concentration” of blood supply to the internal organs, the circulatory system begins to work as if in a “small circle”. There is a decrease in respiratory and heart rhythms to conserve heat, resulting in inactivity of the horse in winter time. Most notable external sign physiological change is the growth of long, thick hair.

Fouling varies greatly in intensity from horse to horse under the same conditions. Breed, health, fatness, gender, type are of great importance. The more “thick-skinned” the horse, the heavier its type, the more overgrown it becomes. As N.D. Alekseev (1992) notes, Yakut horses have the thickest skin compared to horses of other breeds (4.4 + 0.05 mm in winter in the area of ​​the last rib). Compare: in a European warmblood horse, the thickness of the skin in the same place is approximately 3-3.6 mm. There are exceptions related to individual metabolic characteristics. Temperament plays a role: active “thin-skinned” stallions of warm-blooded breeds develop little or no hair at all. For example, Kao lives in the same conditions as our other horses, but does not grow hair at all - he walks in winter in summer wool. Ponies, draft horses, and trotters, as a rule, become more overgrown, they have pronounced “brushes,” the hair growth from wrist to crown increases significantly, and a not very attractive, downright priestly beard appears. The same applies to sick and hungry horses - the body tries to compensate for the lack of a thermally insulating fat layer and lack of nutrition, spending its last reserves on growing hair, although here everything is strictly individual. By the length of a horse's coat you can always accurately judge its health, maintenance and care.

In general, fouling seems to be a common thing for everyone... But what does it cost a horse? I can’t say it better than my husband, so I give a direct quote: “The fouling process takes a significant part of the physiological forces. Just try to calculate how much it costs a horse’s body to raise, maintain, groom, etc. long wool. It wasn’t her husband who bought her a fur coat, she had to take a very large “amount” from her own biological and physiological wealth and spend it on wool, despite the fact that the horse’s biological resource is not so great. Nature has established a certain “insulation standard” for a given zone (north, west, center of Russia). This standard can be easily calculated by analyzing the insulation standards of wild animals that fundamentally live in the natural environment of a given region, by counting and analyzing the length of the coat, the depth and density of the undercoat, and the body temperature (normal) of these animals. This is a normal “natural” program that meets the requirements of the climate and season. The person did not interfere with it.

Through natural selection, this thermal standard and insulation standard have been developed over tens of thousands of years. It is precisely this amount of protective fur, exactly this thickness and depth of the undercoat, exactly this body temperature, as presented by the wild natural inhabitants of the region, that is the norm, ensuring survival, and perhaps some comfort.

The horse here is not suitable as a “trend setter”, being an introduced creature alien to this stripe - no matter in what generation. A kind of “lost exotic dog”.

But adaptive evolutionary changes require millennia!

All that a horse can “present” to the Russian cold is 2.5 - 3 cm of wool. No undercoat.

Having identified the discrepancy between the quality of horse insulation and local natural standards, we can speak with confidence about the physiological suffering of the horse, about the cold causing both physiological and functional harm to the horse. And this, and only this, will be a strictly scientific point of view. The argument, based on the analysis of what people “wear in a given band” for survival, is irrefutable and very serious. Even two hours of winter walking under the influence of the natural climatic conditions of the North-West on the body, unfortunately, is either very uncomfortable for the horse or downright dangerous.”