Man is a warm-blooded creature. It does not freeze in the winter and does not overheat in the summer thanks to a perfect thermoregulation system. With its help, the body temperature of a healthy person at any time of the year is kept within 36–37 ° С. This temperature is kept in the armpit, oral cavity and rectum. On the skin of the face it is 20-22 ° C, on the arms and legs – 25 ° C, on the skin of the abdomen – 34 ° C. The temperature of the internal organs is also different depending on the intensity of metabolism, i.e., chemical reactions in the organ. A certain temperature (thermal energy) is necessary to carry out these reactions, i.e., for the life of the organ. Organs can function only at a certain temperature.
Fluctuations in temperature in the body register receptors.
Receptors of cold (approximately 250,000) and heat (30,000) “work” in the skin. Having caught the shifts, they signal this to the autonomic nerve centers, which ensure the restoration of normal body temperature without the participation of consciousness. For example, in the heat, the blood vessels expand and sweat is increased, in the cold, the vessels narrow and involuntary muscle tremors occur. If the body temperature rises or falls to a certain critical limit, extreme regulation will turn on. From the receptors, signals enter the hypothalamus of the brain, which, together with the centers of the cerebral cortex, will cause a person to change their behavior: go to a cooler or warmer place, change their clothes, or do something else.
To maintain body temperature more or less at the same level is possible only if the reproduction of heat in the body and its loss (into the external environment!) Are balanced. Self-regulation is achieved by chemical (intensification of metabolism) and physical (regulation of heat transfer) thermoregulation. Heat is generated as a result of constantly occurring exothermic reactions in the muscles, liver, and kidneys. Heat losses depend on the location of the organ. The skin and muscles give off more heat and cool faster than internal organs.
The amount of heat released into the environment depends on the area of the body and the size of the lumen of the blood vessels of the skin. The more blood flows through the blood vessels of the skin, the higher the temperature and the more heat is given off. When one liter of sweat evaporates from the skin, a person gives up such an amount of heat by 10 ° C. With urine and feces, 3% of the heat given off is released.
Being in the cold, a person resorts to warm clothing, therefore, a person can successfully protect himself from the cold. Hardening also allows you to significantly shift the limits of perceived external temperature. In order for the system of thermoregulation in any environmental conditions to provide the necessary level of the thermal regime of the internal environment of the body, it should be trained, prepared for vigorous activity in an adverse environment.
Previously, hardening was understood, first of all, or even exclusively as an organism getting used to the cold. Now this concept is interpreted more broadly – hardening means strengthening the body’s resistance to any environmental factors that cause a state of stress, i.e. stress. Such factors are low and high air temperature, excessively low or high air humidity, sudden changes in atmospheric pressure, lack of oxygen in the inhaled air, etc. However, in our daily lives, hardening to excessive cooling and sometimes to overheating remains the most important.
Repeated cooling of the body increases resistance to cold and allows you to further maintain the thermal equilibrium of the body even when a person is very cold. For people who have worked for a long time beyond the Arctic Circle, skin temperature in the cold is much less reduced than for those who have recently arrived in these parts.
The results obtained by hardening children are also very eloquent. A group of first-grade students did foot baths daily — they cooled their feet for several minutes in cold water. Initially, this procedure caused a decrease in skin temperature on the feet by 6-8 ° C, and after 2 months – only by 1 – 1.5 ° C. As a result, among hardened children, colds were observed 3 times less than among non-hardened children.
Hardening is a complex physiological process. By signals that reached the thermoreceptors of the central nervous system, the brain activates the necessary mechanisms. In addition to the nervous system, the system of internal secretion is immediately activated. From the thyroid gland, more hormones that accelerate the metabolism enter the bloodstream. The pituitary gland begins to produce more adrenocorticotropic hormone, under the influence of which the activity of the adrenal glands is intensified. Hormones of the adrenal cortex increase the activity of the body’s defenses, including resistance to infections. This explains why hardened people have infectious diseases less often and in a milder form.
If a person is not tempered against the cold, then he reacts to it as an unconditioned reflex. The heat production is inhibited, the blood vessels of the skin are not narrowing fast enough, etc. The thermoregulation of the hardened organism is improved by conditioned reflex reactions: the heat production increases quickly and expediently and excessive heat loss is prevented.
There is no universal method of hardening to all adverse environmental factors. Hardening adapts the body only to that factor in relation to which it has been systematically tempered for a long time. Whether a person is “frost-resistant” does not mean at all that he is also resistant to heat, and vice versa, the ability to easily withstand high temperatures does not indicate an equally easy adaptability to cold. So that a person is not afraid of “neither heat nor cold”, he should be affected by both high and low temperatures.
There is still a definite connection between adaptation to some external factors. If the body is adapted to heat, then it also tolerates a lack of oxygen (in the mountains, in an airplane). In the heat, metabolism slows down and oxidative processes subside, resulting in a reduced need for oxygen. In people who are accustomed to a lack of oxygen, disability in high altitude places is not reduced.
The process of hardening the body should be gradual, hardening procedures should be carried out carefully, gradually increasing their intensity. It is best to start hardening in childhood, when the thermoregulation system and immunobiological defense mechanisms are only developing. In addition, habits acquired in childhood remain for life.
The hardening effect is short-lived: it lasts only during the hardening of the body and not long after it (1 – 1 ! / 2 months). The body adapts to external factors quickly only if it is necessary to come into contact with their influence constantly. Otherwise, the conditioned reflexes formed as a result of quenching fade, and, suddenly in the cold, in the heat, etc., the body can be unbalanced. Therefore, hardening should be constant and consistent, they should be done daily.
Ways of hardening against the cold have long been known to everyone. These are air, water and the sun in combination with physical exercises. The best results are obtained by a set of hardening techniques, consisting of convection (air and sun baths) and conduct cooling (wiping and dousing, foot baths, bathing, alternating water procedures).
First of all, it tempers any stay in the open air – walks, physical education, work, etc. The hardening effect of cool air is stronger in winter.
A citizen should stay in clean fresh air for as long as possible. Walking is an affordable wellness tool for people of any age. Long walks at an energetic pace improve the activity of the heart, develop a habit of proper and deep breathing, and intensify the metabolism. Moderate physical activity acting on the body when walking, relatively low air temperature and wind temper and tone the nervous system. Cool air, irritating thermoreceptors in the skin, improves the activity of the central nervous system and favorably affects all body functions. As a result, well-being, appetite and sleep improve.
During the day you need to walk for at least an hour, more on weekends. Walking to and from work on foot does not mean wasting time. If you are far from the place of work, then at least part of the road should be walked.
Air alone for hardening is not enough, you need to breathe correctly. One must certainly breathe through the nose, in the cavity of which the air heats up, becomes more humid and clean. Passing through the nasal passages, cool air irritates the nerve endings located in the mucous membrane, making breathing deeper and more rhythmic. When breathing through the nose, almost 25% more air enters the lungs than when breathing through the mouth.
In general, breathing occurs automatically, but it is possible to consciously regulate respiratory movements and increase the supply of oxygen to the body. Train should be exhalation. A smooth and prolonged exhalation should always be followed by a deep breath (the total area of 700 million pulmonary alveoli at this time increases from 90 to 250 m 2 ). More fresh air enters the lungs, and the blood circulating in the pulmonary capillaries is better saturated with oxygen.
Despite the widespread propaganda of physical culture and sports, there are still few physical education enthusiasts. The older a person becomes, the more he ignores her, justifying this with an increase in official and social duties, a desire to do more with his family and self-education. A significant obstacle is also a kind of psychological barrier: a person must force himself to do physical work that is completely unnecessary at first glance. For centuries, parents have dreamed that their children receive an education and live better than they do. And now, when these desires became real, we suddenly fell out of the fire and into the fire. It is perfectly clear that letting physical development go by itself is a crime. For the vast majority, rest will only benefit if the body’s need for movement is satisfied.
Physical education enhances health. The level of fitness achieved in school or student years should be in the daily routine constantly. Not a single physical exercise is an effective means of promoting health. Therefore, a person engaged in physical education must adopt several types at once – gymnastics, jogging, walking, traveling, swimming, skiing, sports, cycling, etc. The minimum required load of a city dweller is as follows: daily morning exercises, workout gymnastics, 3-5 times a week jogging, skiing, cycling or something like that; On weekends, longer walks, sports games and other public events.
Staying in the air trains the adaptive reactions of the body, of course, only if the “training load” is gradually increasing. Therefore, do not rush to remove warm clothes from the closet in the fall. Gradual cooling serves as a natural means of strengthening the body before the onset of winter.
Air baths are useful at any age and should provide a pleasant feeling of warmth, you can not proceed with them with “goose” skin. It is necessary to start with warm ones (air temperature 16-25 ° С), gradually switch to cool (11-16 ° С) and cold air baths (0-10 ° С). Duration at first should not exceed 5-10 minutes, then it can be extended depending on the state of health. As soon as you feel that you are freezing, stop immediately! Air baths should be combined with physical movements, such as daily morning exercises. They can be taken at temperatures below 0 ° C, if you move at the same time, since only muscle activity allows the body to produce sufficient heat in such conditions. In summer, air and sun baths are combined. However, on days when there is no sun, air baths alone are very useful.
Water is a more powerful hardening agent than air. The heat capacity and thermal conductivity of water is greater than that of air, and therefore it cools the body 14 times stronger. In a cool water bath, metabolism is activated more than in air with the same temperature.
Water quenching can be local and general. Since people most often freeze their feet, it is recommended to pay attention to hardening of the feet. Systematic washing of the feet and foot baths in the water, which gradually becomes cooler once in a while, reduce the sensitivity of the legs to cold, weaken the reaction to cold. Particularly positively hardening of the legs affects the state of the upper respiratory tract. Thus, local hardening is actually hardening of the whole organism. Immediately before bedtime, it is not recommended to take cold foot baths, this can interfere with sleep.
The change in ambient temperature occurs not only gradually, but also abruptly, so hardening should set the goal to accustom the body to both small and sharp changes in temperature. Adults and older children can start at a water temperature of 18 ° C and, lowering it by 1 ° every day, go up to 3 ° C, and in some cases up to 0 ° C. In young schoolchildren, the initial water temperature can be 25 ° C, with a gradual decrease to 10 ° C; for preschool children – 28 ° С and 16 ° С, respectively. In the first 3 years, such procedures should not be performed. The foot bath lasts 1-3 minutes, during the bath it is advisable to rub your feet in water.
To adapt to fast and sharp fluctuations in the temperature of the environment, they are tempered with warm and cold water alternately. First, they keep their feet in water or drench them for 2-3 minutes with water at temperatures above 35 ° C, immediately after that for 0.5-1 minutes with water at a temperature of 20 ° C. Every 3-4 days, the temperature of warm water is raised by 1 ° C up to 40–45 ° C, and the temperature of cool water is lowered to 10 ° C.
The alternation of high and low temperature is characteristic of bathing procedures – from steam to cold water (for showering) and back to the shelves. Thus, washing in the bath is an effective general means of hardening against sudden temperature fluctuations. The beneficial effect of the bath, of course, can occur only if it is visited regularly 1 or 2 times a week.
Common hardening procedures also include wiping with a wet hand or towel, dousing, showering, and even a cold bath. The water temperature should be about the same as when hardening the legs. Determining is, again, well-being. After thoroughly wiping the body to dryness, a pleasant feeling of warmth and vigor should arise. It is advisable to carry out water procedures after morning exercises.
Hardening is also bathing and swimming. A person who bathes in a natural body of water is affected by air, the sun, and masses of water in constant motion, which have a mechanical, thermal, and chemical effect on the body. The lower the temperature of the water in the sea, lake or river, the greater its hardening effect. However, here it is also necessary to remember that water with a low temperature should be used gradually.