How to check your breathing rate. V. Types of breathing Normal respiratory rate indicators
The ratio of respiratory rate and heart rate in healthy children in the first year of life is 3-3.5, i.e. One respiratory movement accounts for 3-3.5 heartbeats, in older children – 5 heartbeats.
Palpation.
For palpation chest both palms are applied symmetrically to the areas being examined. By squeezing the chest from front to back and from the sides, its resistance is determined. The younger the child is, the more pliable the chest is. Increased resistance of the chest is called rigidity.
Voice tremors– resonant vibration of the patient’s chest wall when he pronounces sounds (preferably low-frequency), felt by the hand during palpation. For evaluation voice tremors The palms are also placed symmetrically. Then the child is asked to pronounce words that cause maximum vibration of the vocal cords and resonating structures (for example, “thirty-three,” “forty-four,” etc.). In children early age vocal tremor can be examined during screaming or crying.
Percussion.
When percussing the lungs, it is important that the child’s position is correct, ensuring the symmetry of the location of both halves of the chest. If the position is incorrect, the percussion sound in symmetrical areas will be unequal, which may give rise to an erroneous assessment of the data obtained. When percussing the back, it is advisable to invite the child to cross his arms over his chest and at the same time bend slightly forward; when percussing the anterior surface of the chest, the child lowers his arms along the body. It is more convenient to percuss the anterior surface of the chest in young children when the child lies on his back. For percussion of the child's back, the child is seated, and small children must be supported by someone. If the child does not yet know how to hold his head up, he can be percussed by placing his stomach on a horizontal surface or his left hand.
There are direct and indirect percussion.
Direct percussion – percussion with tapping with a bent finger (usually the middle or index finger) directly on the surface of the patient’s body. Direct percussion is more often used when examining young children.
Indirect percussion - percussion with a finger on the finger of the other hand (usually along the phalanx of the middle finger of the left hand), tightly applied with the palmar surface to the area of the patient’s body surface being examined. Traditionally, percussion is done with the middle finger of the right hand.
Percussion in young children should be carried out with weak blows, since due to the elasticity of the chest and its small size, percussion shocks are too easily transmitted to distant areas.
Since the intercostal spaces in children are narrow (compared to adults), the pessimeter finger should be placed perpendicular to the ribs.
When percussing healthy lungs, a clear pulmonary sound is obtained. At the height of inhalation, this sound becomes even clearer, and at the peak of exhalation it shortens somewhat. The percussion sound is not the same in different areas. Right in lower parts due to the proximity of the liver, the sound is shortened; on the left, due to the proximity of the stomach, it takes on a tympanic hue (the so-called Traube space).
Auscultation.
During auscultation, the position of the child is the same as during percussion. Listen to symmetrical areas of both lungs. Normally, in children under 6 months of age, they listen weakened vesicular breathing, from 6 months to 6 years – puerile(breath sounds are louder and longer during both phases of breathing).
The structural features of the respiratory organs in children that determine the presence of puerile breathing are listed below.
Greater elasticity and thin thickness of the chest wall, increasing its vibration.
Significant development of interstitial tissue, reducing the airiness of lung tissue.
After 6 years of age, breathing in children gradually acquires the character of a vesicular, adult type.
Bronchophony – conduction of a sound wave from the bronchi to the chest, determined by auscultation. The patient whispers the pronunciation of words containing the sounds “sh” and “ch” (for example, “cup of tea”). Bronchophony must be examined over symmetrical areas of the lungs.
Instrumental and laboratory studies.
Clinical blood test allows you to clarify the degree of activity of inflammation, anemia, the level of eosinophilia (an indirect sign allergic inflammation).
Sputum culture from tracheal aspirate, bronchial washings (smears from the throat reflect the microflora of only the upper respiratory tract) allows you to identify the causative agent of a respiratory disease (diagnostic titer with a semi-quantitative research method - 10 5 - 10 6), determine sensitivity to antibiotics.
Cytomorphological examination of sputum , obtained by collecting a tracheal aspirate or during bronchoalveolar lavage allows one to clarify the nature of inflammation (infectious, allergic), the degree of activity of the inflammatory process, and conduct a microbiological, biochemical and immunological study of the obtained material.
Puncture of the pleural cavity carried out at exudative pleurisy and other significant accumulations of fluid in the pleural cavity; allows for biochemical, bacteriological and serological examination of the material obtained during puncture.
X-ray method:
Radiography is the main method of x-ray diagnostics in pediatrics; a photograph is taken in a direct projection while inhaling; according to indications, a photograph is taken in a lateral projection;
Fluoroscopy - gives a large radiation dose and therefore should be carried out only according to strict indications: determining the mobility of the mediastinum during breathing (suspicion of a foreign body), assessing the movement of the domes of the diaphragm (paresis, diaphragmatic hernia) and for a number of other conditions and diseases;
Tomography – allows you to see small or merging details of lung lesions and lymph nodes; with a higher radiation dose, it is inferior in resolution to computed tomography;
Computed tomography (mainly cross-sections are used) provides rich information and is now increasingly replacing tomography and bronchography.
Bronchoscopy - a method of visual assessment of the inner surface of the trachea and bronchi, carried out with a rigid bronchoscope (under anesthesia) and a fiberoptic bronchoscope (under local anesthesia).
Bronchoscopy is an invasive method and should be performed only if there is an undeniable indication .
- SHOWINGS for diagnostic bronchoscopy are:
Suspicion of congenital defects;
Aspiration of a foreign body or suspicion of it;
Suspicion of chronic aspiration of food (lavage to determine the presence of fat in alveolar macrophages);
The need to visualize the nature of endobronchial changes in chronic diseases of the bronchi and lungs;
Carrying out a biopsy of the bronchial mucosa or transbronchial lung biopsy.
In addition to diagnostic, bronchoscopy, according to indications, is used with therapeutic purpose: sanitation of the bronchi with the introduction of antibiotics and mucolytics, drainage of the abscess.
During bronchoscopy, it is possible to perform bronchoal volar lavage (BAL) - washing the peripheral parts of the bronchi with a large volume of isotonic sodium chloride solution, which gives important information if alveolitis, sarcoidosis, pulmonary hemosiderosis and some other rare lung diseases are suspected.
Bronchography - contrasting the bronchi to determine their structure and contours. Bronchography is not a primary diagnostic test. Currently, it is used mainly to assess the extent of bronchial lesions and the possibility of surgical treatment, clarifying the form and localization of the congenital defect.
Pneumoscintigraphy - used to assess capillary blood flow in the pulmonary circulation.
Study of respiratory organ functions. IN clinical practice The ventilation function of the lungs is most widely used, which is methodologically more accessible. Violation of the ventilation function of the lungs can be obstructive (impaired passage of air through the bronchial tree), restrictive (reduced gas exchange area, decreased extensibility lung tissue) and combined type. Functional research allows us to differentiate types of external respiration failure, forms of ventilation failure; detect disorders not detected clinically; evaluate the effectiveness of the treatment.
To study the ventilation function of the lungs, spirography and pneumotachometry are used.
Spirography gives an idea of ventilation disturbances, the degree and form of these disturbances.
Pneumochymetry gives an FVC exhalation curve, from which about 20 parameters are calculated both in absolute values and as a percentage of the required values.
Functional tests for bronchial reactivity. Inhalation pharmacological tests are carried out with β 2 -adrenergic agonists to determine latent bronchospasm or select adequate antispasmodic therapy. FVD study carried out before and 20 minutes after inhalation of 1 dose of the drug.
Allergy tests.
Skin (application, scarification), intradermal and provocative tests with allergens are used. The total IgE content and the presence of specific immunoglobulins to various allergens are determined.
Determination of blood gas composition.
Ra O and pa CO 2 are determined, as well as the pH of capillary blood. If long-term continuous monitoring is necessary gas composition blood, transcutaneous determination of blood oxygen saturation (S 2 O 2) is carried out in dynamics in case of respiratory failure.
Software tests
Counting respiratory movements is a standard point in examining a child by a pediatrician. Despite the apparent simplicity and obviousness of this manipulation, NPV can provide important information about how healthy the baby is and whether everything is okay with him. Since the number of breaths per minute in children is much higher than in adults, a special table of respiratory rate norms has been developed for them.
The respiratory system of babies and its features
The first opening of the lungs in a newborn occurs immediately after the baby is born. By this time, the child’s respiratory system is not yet fully developed and has a number of features. Thus, infants have narrow and short nasal passages, which cannot always cope with full breathing. Sharpened under breast-feeding The respiratory system does not allow children to breathe through the mouth, so they may develop shortness of breath and blockage of the nasal passages.
A small child is not yet able to independently clear the nasal passages by blowing his nose, so for normal breathing he especially needs the care and attention of an adult.
Interesting: During sleep, babies can hold their breath when transitioning from a phase REM sleep to slow and back, this is absolutely normal.
How to calculate NPV correctly
This is the simplest procedure that can be done at home. It only requires a stopwatch and the baby at rest, otherwise the data will be unreliable. Perfect timing calculation of the NPV will be a dream, since crying or restlessness of the child can distort the results of the study.
You can measure the baby's respiratory rate visually, by movements of the chest, or by placing your palm on it. An older child can be held by the wrist (under the base of the thumb) and, observing the pulse, count the number of inhalations and exhalations.
Normal respiratory rate in children
The table shows the average values normal frequency respiratory movements in children from 0 to 12 years. In the future, the norm of the child’s respiratory rate coincides with the norm of an adult.
The table clearly shows that respiratory rate decreases with age, while the breathing rate does not depend on a person’s gender. This is due to the fact that with age the respiratory system gradually strengthens, changing at each stage of development.
What does the NPV data say?
If at correct measurement If you find that your child's breathing is rapid or difficult, you should immediately consult a doctor. This may indicate both disorders in the respiratory system and the presence of an infectious disease.
At the same time, increased breathing during physical activity, increased emotionality or a child’s enthusiasm for some activity is completely normal and does not require contacting a specialist.
What is the normal breathing rate for a person?
As a rule, vegetative-vascular dystonia is accompanied by various functional disorders autonomic nervous system, which in turn leads to various violations familiar vital functions body. This is primarily noticeable by changes in heart rate and pressure fluctuations. But often another one is violated important function body - breathing.
Breathing disorders occur most often during panic attacks. The breathing rate increases, hyperventilation of the lungs occurs (an increase in the level of oxygen in the blood and a decrease in the level of carbon dioxide), which, in turn, manifests itself in dizziness and other bad things that are so familiar to those who have experienced PA at least once in their lives.
So the breathing rate
It is convenient to count your breathing rate by placing your hand on your chest. Count for 30 seconds and multiply by two. Normally, in a calm state, the breathing rate of an untrained person is 12-16 inhalations and exhalations per minute. You should strive to breathe at a frequency of 9-12 breaths per minute.Vital capacity (VC) is the amount of air that can be exhaled after the deepest breath has been taken. The value of vital capacity characterizes the strength of the respiratory muscles, the elasticity of the lung tissue and is important criterion respiratory system performance. As a rule, vital capacity is determined using a spirometer in an outpatient setting.
Breathing disorders. Hyperventilation
Respiration carries out gas exchange between external environment and alveolar air, the composition of which is normal conditions varies within a narrow range. During hyperventilation, the oxygen content increases slightly (by 40-50% of the original), but with further hyperventilation (about a minute or more), the CO2 content in the alveoli decreases significantly, as a result of which the level of carbon dioxide in the blood drops below normal (this condition is called hypocapnia). Hypocapnia in the lungs during deep breathing shifts the pH to the alkaline side, which changes the activity of enzymes and vitamins. This change in the activity of metabolic regulators disrupts the normal course of metabolic processes and leads to cell death. To maintain the constancy of CO2 in the lungs, the following defense mechanisms arose during evolution:
spasms of the bronchi and blood vessels;
increased production of cholesterol in the liver as a biological insulator that seals cell membranes in the lungs and blood vessels;
decline blood pressure(hypotension), which reduces the removal of CO2 from the body.
But spasms of the bronchi and blood vessels reduce the flow of oxygen to the cells of the brain, heart, kidneys and other organs. A decrease in CO2 in the blood increases the connection between oxygen and hemoglobin and makes it difficult for oxygen to enter cells (Verigo-Bohr effect). A decrease in oxygen flow into tissues causes oxygen starvation tissues – hypoxia. Hypoxia, in turn, leads first to loss of consciousness and then to death of brain tissue.
The ending of the quote is somewhat gloomy, but it’s a fact and there’s no getting around it. In case panic attack to fatal outcome it won’t work out, the body won’t allow itself to be killed, but you can lose consciousness. This is why it is important to learn how to control your breathing during a panic attack. Breathing into a paper bag helps a lot with hyperventilation: the CO2 level does not drop so quickly, you feel less dizzy, and this makes it possible to calm down and regulate your breathing.
Respiratory rate (RR) and vital capacity. Breathing at rest should be rhythmic and deep. The normal respiratory rate in an adult is 14-18 times per minute. Under load it increases 2-2.5 times. An important indicator of respiratory function is the vital capacity of the lungs (VC) - the volume of air obtained during the maximum exhalation made after the maximum inhalation. Normally in women it is 2.5 - 4 l, in men it is 3.5-5 l.
Blood pressure (BP). Systolic pressure (max) is the pressure during systole (contraction) of the heart, when it reaches its greatest value throughout the cardiac cycle. Diastolic pressure (min) - determined at the end of diastole (relaxation) of the heart, when it continues cardiac cycle reaches a minimum value.
Formula ideal pressure for each age:
Max. BP = 102+ (0.6 x number of years) min. BP = 63+ (0.5 x number of years)
The World Health Organization proposes to consider normal numbers blood pressure for systolic (max.) - 100 - 140 mm Hg; for diastolic 80-90 mm Hg.
58. Functional tests and tests
The level of the functional state of the body can be determined using functional tests and tests.
Orthostatic test. The pulse is calculated in a lying position after 5-10 minutes of rest, then you need to stand up and measure the pulse in a standing position. Based on the difference in heart rate while lying down and standing, one can judge functional state cardiovascular and nervous systems. The difference is up to 12 beats/min - good condition physical fitness, from 13 to 18 beats/min - satisfactory, 19-25 beats/min - unsatisfactory, i.e. lack of physical fitness, more than 25 beats/min - indicates overwork or illness.
Stange's test (holding your breath while inhaling). After 5 minutes of rest while sitting, take 2-3 deep breaths in and out, and then, after doing full breath hold their breath, the time is noted from the moment the breath is held until it stops.
The average indicator is the ability to hold your breath while inhaling for untrained people for 40-55 seconds, for trained people - for 60-90 seconds or more. With increasing training, the time you hold your breath increases; in case of illness or fatigue, this time decreases to 30-35 seconds.
This test characterizes the body's resistance to oxygen deficiency.
One-time test.
Before performing a single-stage test, rest while standing, without moving for 3 minutes. Then the heart rate is measured for one minute. Next, perform 20 deep squats in 30 seconds from the starting position with feet shoulder-width apart, arms along the body. When squatting, the arms are brought forward, and when straightening, they are returned to their original position. After performing squats, heart rate is calculated for one minute.
The assessment determines the percentage increase in heart rate after exercise. A value of 20% means excellent response cardiovascular system for load, from 21 to 40% - good,
from 41 to 65% - satisfactory,
from 66 to 75% - bad,
from 76 and more - very bad.
Genchi test (holding your breath while exhaling). It is performed in the same way as the Stange test, only the breath is held after a complete exhalation. Here, the average indicator is the ability to hold your breath while exhaling for untrained people for 25-30 seconds, for trained people for 40-60 seconds. and more.
Ruffier's test. To assess the activity of the cardiovascular system, you can use the Ruffier test. 1 After a 5-minute calm state in a sitting position, count your pulse for 10 seconds (P1), then perform 30 squats within 45 seconds. Immediately after squats, count your heart rate for the first 10 seconds (P2) and a minute (P3) after the load. The results are assessed by an index, which is determined by the formula:
6 x (P1+ P2+ P3) - 200
Ruffier index =
Cardiac performance assessment:
Ruffier index
0 - athletic heart
0, 1 - 5 - "excellent" (very good heart)
5, 1 - 10 - “good” (good heart)
10, 1 - 15 - “satisfactory” (heart failure)
15 1 - 20 - “poor” (severe heart failure)
25 - 50% - good,
from 50 - 75% bad.
Test to check and evaluate general endurance.
It is carried out using control exercises of 2 types: overcoming a medium, long distance or overcoming the greatest possible distance in certain time. Examples of these exercises are:
1) running and cross-country at 1000, 2000, 2500, 3000, 5000m;
swimming 200, 400, 500 m,
2) run 12 min.
The most substantiated assessments of general endurance are based on the K. Cooper test. This is a 12-minute run covering a maximum distance (km).
Ellipses
Creating ellipses and elliptical arcs is done using the ELLIPSE command.
Ellipse axis end point or [Arc/Center]: (Specify axis endpoint of ellipse or :)
Second axis end point: (Specify other endpoini of axis:)
If you select the option Turn(Rotation), then the ellipse will be constructed as a projection of a circle rotated in space relative to the XY plane (more precisely, relative to the main axis) by the angle you specify. Acceptable range of angles: 0-89.4 (if the angle is zero, then a regular circle is obtained).
Option Center(Center)
Ellipse center: (Specify center of ellipse:)
Axis end point: (Specify endpoint of axis:)
After this, a final question is issued, as in the case we considered above (Length of other axis or [Rotation]: (Specify distance to other axis or :)).
To build an elliptical arc you need to select the option Arc(Arc).
Elliptical arc axis end point or [Center]:
(Specify axis endpoint of elliptical arc or :) Next:
Second axis end point: (Specify other endpoint of axis:) Next request:
Length of other axis or [Rotation]: (Specify distance to other axis or :)
Starting angle or [Option]: (Specify start angle or :)
The starting angle is set by a number or using the mouse relative to the first axis (counting counterclockwise, starting from the first point of the axis). Next:
End corner or [Option/Inside corner]:
(Specify end angle or :)
Heart is hollow muscular organ, the “pump” of our body that pumps blood through blood vessels: arteries and veins.
Through arteries, blood flows from the heart to organs and tissues, while it is rich in oxygen and is called arterial. Blood flows through the veins to the heart, while it has already given oxygen to each cell of the body and taken it from the cells carbon dioxide, therefore this blood is darker and is called venous.
Arterial called pressure, which is formed in the arterial system of the body during heart contractions and depends on complex neurohumoral regulation, magnitude and speed cardiac output, frequency and rhythm of heart contractions and vascular tone.
There are systolic (SD) and diastolic pressure(DD). Blood pressure is recorded in millimeters of mercury (mmHg). Systolic is the pressure that occurs in the arteries at the moment of maximum rise pulse wave after ventricular systole. Normally, in a healthy adult, DM is 100–140 mmHg. Art. The pressure maintained in the arterial vessels during ventricular diastole is called diastolic; normally in a healthy adult it is 60–90 mmHg. Art. Thus, human blood pressure consists of two values - systolic and diastolic. SD (larger indicator) is written first, DD (smaller indicator) is written second, separated by a fraction. An increase in blood pressure above normal is called hypertension or hypertension. The difference between DM and PP is called pulse pressure (PP), which is normally 40 - 50 mmHg. Blood pressure below normal is called hypotension or hypotension.
In the morning, blood pressure is lower by 5-10 mmHg than in the evening. Art.. A sharp drop in blood pressure is life-threatening! It is accompanied by pallor, severe weakness, and loss of consciousness. Low blood pressure disrupts the normal course of many vital important processes. So, when systolic pressure drops below 50 mm Hg. Art. urine production ceases and renal failure develops.
Blood pressure is measured using the indirect sound method, proposed in 1905 by the Russian surgeon N.S. Korotkov. Devices for measuring pressure have the following names: Riva-Rocci apparatus, or tonometer, or sphygmomanometer.
Currently, electronic devices are also used that make it possible to determine blood pressure using a non-sound method.
To study blood pressure, it is important to consider the following factors: the size of the cuff, the condition of the membrane and tubes of the phonendoscope, which may be damaged.
Pulse- these are rhythmic vibrations of the arterial wall caused by the release of blood into arterial system during one heartbeat. There are central (on the aorta, carotid arteries) and peripheral (on the radial, dorsal artery of the foot and some other arteries) pulse.
For diagnostic purposes, the pulse is determined in the temporal, femoral, brachial, popliteal, posterior tibial and other arteries.
The pulse is most often examined in adults radial artery, which is located superficially between the styloid process radius and the tendon of the internal radial muscle.
When examining the pulse, it is important to determine its frequency, rhythm, filling, tension and other characteristics. The nature of the pulse also depends on the elasticity of the artery wall.
Frequency is the number of pulse waves per minute. Normally, a healthy adult has a pulse of 60-80 beats per minute. An increased heart rate of more than 85-90 beats per minute is called tachycardia. A heart rate rate of less than 60 beats per minute is called bradycardia. The absence of a pulse is called asystole. With an increase in body temperature at HS, the pulse increases in adults by 8-10 beats per minute.
The pulse rhythm is determined by the intervals between pulse waves. If they are the same, the pulse is rhythmic (correct); if they are different, the pulse is arrhythmic (incorrect). In a healthy person, the contraction of the heart and the pulse wave follow each other at regular intervals.
Pulse filling is determined by the height of the pulse wave and depends on the systolic volume of the heart. If the height is normal or increased, then it can be felt normal pulse(full); if not, then the pulse is empty. Pulse voltage depends on blood pressure and is determined by the force that must be applied until the pulse disappears. At normal pressure the artery is compressed with moderate force, so the normal pulse is of moderate (satisfactory) tension. At high blood pressure the artery is compressed by strong pressure - such a pulse is called tense. It is important not to make a mistake, since the artery itself can be sclerotic. In this case, it is necessary to measure the pressure and verify the assumption that has arisen.
With low blood pressure, the artery is easily compressed, and the tension of the pulse is called soft (relaxed).
An empty, relaxed pulse is called a small filamentous pulse.
Pulse study data is recorded in two ways: digital - in medical documentation, magazines, and graphic - in temperature sheet in red pencil in the column “P” (pulse). It is important to determine the division value on the temperature sheet.
The respiratory system provides the gas exchange necessary to maintain life and also functions as a vocal apparatus. Function respiratory system comes down to supplying blood sufficient quantity oxygen and remove carbon dioxide from it. Life without oxygen is not possible for humans. Exchange of oxygen and carbon dioxide between the body and environment called breathing.
Breathing is a single process consisting of 3 parts:
1. External breathing– gas exchange between the external environment and the blood of the pulmonary capillaries.
2. Transfer of gases (using blood hemoglobin).
3. Internal tissue respiration - gas exchange between blood and cells, as a result of which the cells consume oxygen and release carbon dioxide. Watching breathing, special attention should be given to color change skin, determining the frequency, rhythm, depth of respiratory movements and assessing the type of breathing.
The respiratory movement is carried out by alternating inhalation and exhalation. The number of breaths in 1 minute is called the respiratory rate (RR).
In a healthy adult, the rate of respiratory movements at rest is 16-20 per minute; in women it is 2-4 breaths more than in men. NPV depends not only on gender, but also on body position, state of the nervous system, age, body temperature, etc.
Observation of breathing should be carried out unnoticed by the patient, since he can arbitrarily change the frequency, rhythm, and depth of breathing. NPV is related to heart rate on average as 1:4. When body temperature rises by 1°C, breathing becomes more frequent by an average of 4 respiratory movements.
Possible changes breathing pattern
There is a distinction between shallow and deep breathing. Shallow breathing may be inaudible from a distance. Deep breathing, heard at a distance, is most often associated with a pathological decrease in breathing.
TO physiological types breathing includes thoracic, abdominal and mixed types. In women, thoracic breathing is more common; in men, abdominal breathing is more common. At mixed type breathing occurs uniform expansion of the chest of all parts of the lung in all directions. Types of breathing are developed depending on the influence of both external and internal environment body. When the rhythm and depth of breathing is disturbed, shortness of breath occurs. There is inspiratory dyspnea - this is breathing with difficulty inhaling; expiratory - breathing with difficulty exhaling; and mixed - breathing with difficulty inhaling and exhaling. Rapidly developing severe shortness of breath is called suffocation.
2. Mechanisms of heat generation and heat transfer pathways
In an adult healthy person, body temperature is constant and when measured in the armpit, it ranges from 36.4-36.9°.
Heat is generated in all cells and tissues of the body as a result of the metabolism occurring in them, i.e. oxidative processes, decay nutrients, mainly carbohydrates and fats. The constancy of body temperature is regulated by the relationship between the formation of heat and its release: the more heat is generated in the body, the more it is released. If at muscle work the amount of heat in the body increases significantly, its excess is released into the environment.
With increased heat production or increased heat transfer, skin capillaries expand and then sweating begins.
Due to the expansion of skin capillaries, a rush of blood occurs to the surface of the skin, it turns red, becomes warmer, “hotter”, and due to the increased temperature difference between the skin and the surrounding air, heat transfer increases. When sweating, heat transfer increases because a lot of heat is lost when sweat evaporates from the surface of the body. That is why, if a person works hard, especially when high temperature air (in hot workshops, a bathhouse, under the scorching rays of the sun, etc.) he turns red, he becomes hot, and then he begins to sweat.
Heat transfer, although to a lesser extent, also occurs from the surface of the lungs - the pulmonary alveoli.
A person exhales warm air saturated with water vapor. When a person is hot, he breathes more deeply and frequently.
Small quantity heat is lost in urine and feces.
With increased heat generation and reduced heat transfer, body temperature rises, a person gets tired faster, his movements become slower, sluggish, which somewhat reduces heat generation.
A decrease in heat generation or a decrease in heat transfer, on the contrary, is characterized by a narrowing of the skin blood vessels, paleness and coldness of the skin, due to which heat transfer decreases. When a person is cold, he involuntarily begins to tremble, that is, his muscles begin to contract, both embedded in the thickness of the skin (“skin tremors”) and skeletal ones, as a result of which heat generation increases. For the same reason, he begins to make rapid movements and rub the skin to increase heat generation and cause hyperemia of the skin.
Heat generation and heat transfer are regulated by the central nervous system.
The centers that regulate heat exchange are located in the interstitial brain, in the subthalamic region under the controlling influence of the brain, from where the corresponding impulses through the autonomic nervous system spread around the periphery.
Physiological adaptability to changes in external temperature, like any reaction, can only occur to certain limits.
If the body overheats excessively, when the body temperature reaches 42-43°, a so-called heat stroke occurs, from which a person can die if appropriate measures are not taken.
With excessive and prolonged cooling of the body, the body temperature begins to gradually decrease and death from freezing may occur.
Body temperature is not a constant value. The temperature value depends on:
- time of day. Minimum temperature happens in the morning (3-6 hours), maximum - in the afternoon (14-16 and 18-22 hours). Night workers may have the opposite relationship. The difference between morning and evening temperatures is healthy people does not exceed 1 0 C;
- motor activity. Rest and sleep help lower the temperature. Immediately after eating, there is also a slight increase in body temperature. Significant physical and emotional stress may cause an increase in temperature by 1 degree;
Hormonal background. In women during pregnancy and menstrual period the body rises slightly.
Age. In children it is higher on average by 0.3-0.4°C than in adults; in old age it may be slightly lower.
