The normal functioning of the human body is possible at a temperature of its internal organs and blood of about 37 ° C, and temperature fluctuations should not exceed 1.5 ° C.

Overheating of the body (hyperthermia) is a condition characterized by a violation of the thermal balance, an increase in the thermal content of the body. The main way of heat transfer in human hyperthermia is the evaporation of moisture from the surface of the body and through the respiratory tract.. It should be noted that overheating is not associated with a primary violation of the function of thermoregulation..

Overheating of the human body is observed in industries with a high ambient temperature or in conditions that impede heat transfer from the surface of the body, as well as in areas with a hot climate. At a high ambient temperature, overheating of the body is facilitated by an increase in heat production that occurs during muscular work, especially in clothes that are impervious to water vapor, high humidity and stillness of the air.. In conditions of difficult heat transfer, young children easily overheat, in whom the thermoregulation system is not sufficiently formed, as well as adults with impaired sweating function..

The conducted studies of the effect of high temperatures on the human body, according to the nature of changes in heat exchange, the cardiovascular and respiratory systems, made it possible to distinguish four degrees of overheating of the body (according to A. Azhaev):.

- I degree (stable adaptation) - ambient temperature is about 40 ° C. Heat transfer is carried out by evaporation of moisture from the surface of the body and from the respiratory tract. It is equal to the heat load, and the body temperature does not rise.. The general condition is satisfactory, complaints are reduced to a feeling of warmth, lethargy and drowsiness, unwillingness to work and move are often felt.;

– II degree (partial adaptation) – ambient temperature is about 50 ° C. The heat load is not compensated by the evaporation of moisture, and heat is accumulated in the body. Body temperature can reach 38.5°C. Systolic pressure rises by 5-15 mmHg. st. , and diastolic decreases by 10-20 mm Hg. st. The minute and systolic volumes of the heart, pulmonary ventilation, the amount of absorbed oxygen and released carbon dioxide increase.. Pulse quickens by 40-60 beats. There is a sharp hyperemia of the skin, profuse sweating. Characteristic feeling of heat;

— III degree (failure of the device) — when exposed to a temperature of 60°C and above. Body temperature can reach 39.5-40°C. Systolic pressure rises by 20-30 mmHg. st. , and diastolic decreases by 30-40 mm Hg. st. , the effect of “infinite tone” (zero diastolic pressure) can be heard. The number of heartbeats increases to 160 beats / min. , but the systolic volume of the heart decreases. By increasing pulmonary ventilation, the amount of absorbed oxygen and released carbon dioxide increases.. The skin is sharply hyperemic. Sweat drips down. Patients complain of a deterioration in well-being, a feeling of intense heat, palpitations, pressure in the temples and headache. There may be agitation, restlessness;

- IV degree (lack of adaptation) - this, in fact, is a heat stroke, when there is a sharp violation of the activity of the cardiovascular and central nervous systems.

It should be noted that the severity of overheating of the body depends not only on the magnitude of the ambient temperature, but also on the duration of its impact on the human body.. Thus, heat stroke can also occur at temperatures up to 40 ° C with prolonged exposure to these conditions..

The development of heat stroke is most expected: in workers in hot shops with a long stay in a room with a high temperature and strenuous physical work; construction sites, excavation and mining operations carried out on hot days, in places with high humidity; during marches of military units made on summer days with full gear, long transitions, especially in the subtropical and tropical zones; during long hiking trips in the absence of sufficient training for their participants.

Overheating of the body is accompanied by increased sweating with a significant loss of water and salts by the body, which leads to thickening of the blood, an increase in its viscosity, difficulty in blood circulation and tissue hypoxia.. An important role in the pathogenesis of heat stroke is played by disorders of the water and electrolyte balance due to impaired sweating and the activity of the hypothalamic center of thermoregulation..

Often heat stroke is accompanied by the development of collapse. Circulatory disorders are promoted by the toxic effect on the myocardium of excess potassium in the blood released from erythrocytes.. With heat stroke, the regulation of respiration and kidney function, various types of metabolism (protein, carbohydrate, fat) suffer. The central nervous system is affected with the development of hyperemia and edema of the membranes and brain tissue, multiple hemorrhages. Also, with heat stroke, plethora of internal organs is noted, small-point hemorrhages under the pleura, epicardium and endocardium, in the mucous membrane of the stomach, intestines. Often there is pulmonary edema, myocardial dystrophy.

The clinical picture of heat stroke Onset is acute, the course is rapid. Sometimes the clinical picture resembles the clinic of acute cerebrovascular accident.. According to the severity of the course, heat stroke is divided into three forms.

Light form. Adynamia, headache, nausea, rapid breathing, tachycardia. Temperature is normal or subfebrile. Skin is not changed. If the victim is as quickly as possible to create comfortable conditions, then all the symptoms of hyperthermia also quickly disappear..

Medium severity. Sharp adynamia. Headache with nausea and vomiting, dizziness, unsteadiness of movement, short-term loss of consciousness (fainting). Breathing fast, tachycardia. The skin is moist, hyperemic. Sweating is increased. Body temperature 39-40°C. If therapeutic measures are started on time, then the functions of the body are normalized..

Severe form. The beginning is acute. Consciousness is confused, up to stupor, stupor, coma. Clonic and tonic seizures. Psychomotor agitation, delusions, hallucinations. Breathing is frequent, shallow, arrhythmic. Pulse 120-140 beats, thready. Heart sounds are muffled. Skin is hot and dry. Body temperature 41-42 ° C and above. Anuria. ECG shows signs of diffuse myocardial damage. Residual nitrogen and urea increase in the blood and the amount of chlorides decreases. Mortality in severe form of heat stroke reaches 20-30%.

Intensive care for heat stroke Any uncontrolled hyperthermia requires immediate treatment, because. the slightest delay can cause irreversible changes in brain structures. Required: Uncover the victim (sick). Put ice or containers with ice water on the area of \u200b\u200blarge vessels. IM 1-2 ml of a 2.5% solution of diprazine (Pipolfen) or 1 ml of a 0.5% solution of diazepam (Seduxen, Relanium) to avoid muscle tremors during rewarming (trembling can further increase hyperthermia). Enter in / in 1-2 ml of a 25% solution of analgin. In severe hyperthermia, it may be necessary to administer antipsychotics as part of the so-called lytic cocktails: an antihistamine, a non-narcotic analgesic, a sedative, an antipsychotic. Start intravenous drip of 0.9% sodium chloride solution or other saline crystalloid solution. In the first 2-3 hours, it is necessary to inject up to 1000 ml of the solution, correcting the level of blood electrolytes, especially K + and Ca ++. With a fall in cardiac activity, cardiac glycosides are prescribed (for example, digoxin 0.025% - 1 ml) or inhalation of isadrin through an inhaler. Start oxygen inhalation.

Sunstroke A type of heatstroke is sunstroke, which is defined as a pathological syndrome manifested by damage to the central nervous system during prolonged exposure to direct sunlight on the head area..

Clinical picture Complaints: headache, general malaise, dizziness, feeling of weakness, nausea, vomiting.

Objectively marked hyperemia of the face, shortness of breath, tachycardia, fever, profuse sweating. Sometimes nosebleeds, loss of consciousness, the occurrence of a convulsive syndrome are possible..

First aid The patient should be placed in the shade or in a cool room.. Lay flat, legs up. Unfasten clothes, trouser belt. Splash cold water on your face. Cool down your head, for which you can use a cooling thermal pack available in a standard car first-aid kit. Wipe the whole body with a wet towel. A good effect is achieved by inhaling ammonia vapors.. If conscious, drink cold water.

Prevention of heat stroke is determined in each individual case by a specific situation.. For example, long transitions in a hot period are recommended to be carried out in cooler hours of the day in light porous clothes, more often to arrange halts in shady ventilated places.. It is necessary to observe the rule of the drinking regime, thanks to which it is possible to directly correct the water-salt metabolism in the body. Instead of water, you can use cold acidified or sweetened tea, rice or cherry broth, bread kvass. A wider intake of carbohydrates, dairy products is recommended with a restriction of products containing acid radicals (cereals, etc.).. The high ambient temperature makes it necessary to transfer the main meal to the evening hours, with consumption for breakfast - 35, for lunch - 25, for dinner - 40% of the daily diet.

In hot shops, devices are installed for air cooling by spraying water, water procedures are widely used (showers, douches, etc.).. ), set breaks in work, limit the intake of protein and fatty foods.

Preliminary training is important in the prevention of heat stroke, with the help of which it is possible to achieve an increase in adaptation to the action of thermal factors..

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