Vibration as an occupational hazard is a mechanical vibrational motion directly transmitted to the human body or to its individual parts. As a result of the mechanization of many types of work and the use of pneumatic and electric tools, its importance has increased dramatically, and at present, vibration disease occupies one of the first places among occupational diseases.

With regard to the danger of vibration disease, vibration with a frequency of 16-250 Hz is of the greatest importance.

It is customary to distinguish local (local) and general vibration: the first is transmitted to the hands or other limited areas of the body, the second - to the whole body (stay on an oscillating platform, seat).

The effect of vibration on workers is often combined with the influence of other industrial hazards: noise, cooling microclimate, uncomfortable body position.

The effect of vibration on the body. Vibration, depending on its parameters (frequency, amplitude), can have both positive and negative effects on individual tissues and the body as a whole. For physiotherapeutic purposes, vibration is used to improve trophism, blood circulation in tissues in the treatment of certain diseases. However, industrial vibration, being transmitted to healthy tissues and organs and having a significant amplitude and duration of action, turns out to be a harmful influencing factor.

Vibration causes primarily neurotrophic and hemodynamic disturbances. In vessels of small caliber (capillaries, arterioles) spastic-atonic states appear, their permeability increases, and nervous regulation is disturbed. Vibration, temperature and pain sensitivity of the skin changes. When working with a mechanized hand tool, a “dead finger” symptom may occur: loss of sensitivity, whitening of fingers and hands. Workers complain of chilly hands, aching pains in them after work and at night. The skin between attacks has a marbled appearance, cyanotic. In some cases, swelling, changes in the skin on the hands (cracks, coarseness), hyperhidrosis of the palms are found. Osteoarticular and muscle changes are characteristic. Dystrophic processes cause changes in the structure of bones (osteoporosis, growths, etc.), muscle atrophy. Possible deformation of the wrist, elbow, shoulder joints with impaired musculoskeletal function.

The disease is general in nature, as evidenced by rapid fatigue, headaches, dizziness, and increased irritability. There may be complaints of pain in the heart and stomach, increased thirst: weight loss, insomnia. Astheno-vegetative syndrome is accompanied by cardiovascular disorders: hypotension, bradycardia, ECG changes. A physical examination may reveal changes in skin sensitivity, tremors of the hands, tongue and eyelids.

When exposed to general vibration, changes in the central nervous system are more pronounced: complaints of dizziness, tinnitus, drowsiness, pain in the calf muscles. Changes in the EEG, conditioned and unconditioned reflexes, memory impairment, and impaired coordination of movements are objectively detected. There is an increase in energy consumption and weight loss. More often than under the action of local vibration, vestibular disorders are detected. Vibration, when combined with noise, can alter hearing. In this case, a deterioration in the perception of sounds of not only high, but also low frequencies is characteristic. Sometimes visual disturbances are detected: a change in color perception, the boundaries of the visual field, a decrease in visual acuity. On the part of the cardiovascular system, there is an instability of blood pressure, a predominance of hypertensive phenomena, and sometimes a sharp drop in blood pressure by the end of the work. Cases of spasm of coronary vessels, development of myocardial dystrophy are possible. Lesions of the osteoarticular apparatus are mainly localized in the legs and spine. The action of general vibration can contribute to disorders of the functional state of internal organs, the appearance of pain in the stomach, lack of appetite, nausea, and frequent urination. Pathological changes in the pelvic organs can be accompanied by impotence in men, menstrual irregularities in women, prolapse of the pelvic organs, and increased gynecological morbidity.

The initial forms of vibration disease are easier to reverse development after temporary cessation of contact with vibration sources, the introduction of a rational work regime, the use of massage, water procedures, etc. In the later stages of the disease, long-term treatment and complete elimination of vibration during work are necessary.

In theory, it would seem that it makes no difference what instrument vibration is caused by: all other things being equal, its parameters play the main role. In principle, this is the case, but this is true only "other things being equal." In reality, however, the nature of the profession determines some features in the course of the disease, for example, a local process develops more sharply. So, as noted by researchers in Japan, gastric diseases are widespread among truck drivers. It is also known that the symptoms of vibration sickness are accompanied by radiculitis in logging tractor drivers. Loss of visual acuity is common in pilots, especially in helicopter pilots. As shown in special studies, single, and short-term - about 20-30 minutes. vibration, increases the time for solving elementary problems, i.e. impairs attention and mental activity, while up to 30% of decisions are wrong.

Research has revealed a very important biological pattern. It turns out that weakening of attention is observed only at certain frequencies of the order of 10-12 Hz, while other frequencies, higher and lower, but with the same acceleration, do not cause such changes. This regularity provides a key to elucidating the characteristics of vibration sickness diseases associated with a particular production activity. Each machine or unit generates along with the mass of side frequencies (harmonics) one fundamental for this machine. This frequency determines the specificity of the disease.

If vibration with a frequency higher than 15 Hz (especially a frequency of 60-90 Hz) affects a person along his body in the direction of the vertical axis, then visual acuity decreases, the ability to follow the oscillatory movements of an object is lost already at frequencies of 1-2 Hz and almost disappears at 4 Hz ... This simple example shows the danger of transport vibration: drivers, pilots, drivers of other vehicles cease to distinguish moving objects.

The vibration frequency caused by road irregularities and imperfections in land transport is in the range up to 15 Hz, i.e. is a real hazard and can cause accidents.

Vibration disturbs a person's speech. At frequencies from 4 to 10 Hz, speech is distorted and sometimes interrupted. To maintain clear and correct speech requires special training, since intelligible speech is difficult to maintain with a vibration level of 0.3 dB. It is easy to understand how this affects the communication of pilots and astronauts with ground control posts.

Pilots, chauffeurs, and machinists have the same symptoms of vibration sickness as workers. Diseases in helicopter pilots are especially severe. In flight, low-frequency vibrations occur, which are poorly damped by the human body and have a destructive effect on the entire body, primarily on the nervous system. Disorders of nervous and cardiovascular activity in pilots are found almost 4 times more often than in representatives of other professions, and vibration plays a significant role here.

Long-term exposure to vibration on the human body leads to serious consequences called "vibration disease". This is a professional pathology that occurs as a result of prolonged exposure to the human body of industrial vibration that exceeds the maximum permissible level (MPL). As a rule, middle-aged men are ill.

Vibration can act both locally (for example, on working hands), and on the entire body. But in any case, it is capable of spreading, affecting the nervous and musculoskeletal system. Vibration is damped due to the elastic properties of muscles, ligaments, cartilage.

In addition, the cardiovascular system suffers from prolonged vibration, and especially the microcirculatory bed (small vessels in which oxygen is directly returned by the blood and carbon dioxide is utilized from the tissues).

With general vibration, the organ of balance (vestibular apparatus) is often affected, which is accompanied by dizziness, shaky, unsteady gait, such patients are often worried about nausea, sometimes double vision. Travel in transport is more difficult, especially on trains.

The body reactions listed above are specific to vibration disease and their presence is mandatory for a diagnosis.

Nonspecific symptoms of vibration disease include:

• disorders of immunity, endocrine function, metabolism;
• thickening of the blood;
• prolapse of the abdominal and pelvic organs, which causes disruption of their functions, and first of all - the gastrointestinal tract. When omission appears heaviness, pain in the epigastric region, flatulence, the risk of intestinal obstruction, bile stagnation increases.

The defeat of the nervous system lies in the fact that as a result of the direct action of vibration on the receptors, their excitability increases. This leads to chronic (stagnant) activation of the centers of vibration sensitivity, from which the excitement spreads to the neighboring centers of the cerebral cortex (vasomotor, center of thermoregulation, pain). All this forms a syndrome of autonomic-sensory polyneuropathy (aching pains in the arms, legs, muscles, their trembling, cold hands, feet are constantly freezing, swelling is possible).

Angiodystonic syndrome (violation of the tone of the blood vessels) is also very characteristic of vibration disease. It arises as a result of damage to both the vasomotor center and the direct mechanical effect of vibration on the vessels. Vibration contributes to damage to the inner wall of the artery, blood clots appear here, which are transferred to the smaller vessels with the blood flow and block them. As a result, the affected part of the body turns blue, becomes cold, and its sensitivity is lost. After a while, long-term non-healing ulcers may appear. This is also facilitated by the vasoconstrictor effect of high-frequency vibration, an increase in blood viscosity. In the case of general vibration, the risk of heart attacks, strokes, arterial hypertension increases significantly.

As mentioned above, vibrational vibrations are damped by the soft tissues of the musculoskeletal system - this is the positive side. However, over time, ligaments, cartilage and muscles, which are under constant vibration, become very rough, dense, scar tissue appears in them (like calluses on the palms after prolonged physical exertion) - these are negative consequences. Such scars interfere with the normal functioning of organs: the ligaments become weaker, they break more easily under heavy load; movements in the joints are difficult, pains, swelling appear here; muscle fatigue, pain increases, muscle strength decreases, they decrease in size (atrophy).

Treatment for vibration sickness is based on two principles. The first is the elimination of the effects of vibration on the body (etiological principle).

The second is a comprehensive treatment of all the symptoms that have arisen. Here, analgesics, drugs that improve blood circulation, neuroprotectors are used, physiotherapy, reflexology and others are prescribed to the musculoskeletal system (pathogenetic and symptomatic principle of treatment).

VIII. Industrial vibrations

3. The effect of vibrations on a person

Vibration is one of the factors with high biological activity. The severity of response reactions is mainly due to the power of the energy impact and the biomechanical properties of the human body as a complex oscillatory system. The power of the oscillatory process in the contact zone and the time of this contact are the main parameters that determine the development of vibration pathologies, the structure of which depends on the frequency and amplitude of oscillations, the duration of exposure, the place of application and the direction of the axis of the vibration effect, the damping properties of tissues, resonance phenomena and other conditions.

There is no linear relationship between the response of the body and the level of the impacting vibration. The reason for this phenomenon is seen in the resonance effect. With an increase in vibration frequencies of more than 0.7 Hz, resonant vibrations in human organs are possible. The resonance of the human body, of its individual organs occurs under the influence of external forces when the natural frequencies of vibrations of internal organs coincide with the frequencies of external forces. The area of ​​resonance for the head in a sitting position with vertical vibrations is located in the zone between 20 - 30 Hz, with horizontal vibrations - 1.5 - 2 Hz.

The resonance is of particular importance in relation to the organ of vision. The visual disturbance appears in the frequency range between 60 and 90 Hz, which corresponds to the resonance of the eyeballs. For organs located in the chest and abdominal cavity, the resonant frequencies are 3 - 3.5 Hz. For the whole body in a sitting position, resonance occurs at frequencies of 4 - 6 Hz.

Vibration pathology is in second place (after dust) among occupational diseases. Considering health disorders during vibration exposure, it should be noted that the frequency of diseases is determined by the magnitude of the dose, and the features of clinical manifestations are formed under the influence of the vibration spectrum. There are three types of vibration pathology from the effects of general, local and jerky vibrations.

When the general vibration acts on the body, the nervous system and analyzers primarily suffer: vestibular, visual, tactile. Vibration is a specific irritant for the vestibular analyzer, with linear accelerations for the otolith apparatus located in the vestibule sacs, and angular accelerations for the semicircular canals of the inner ear.

Dizziness, movement coordination disorder, motion sickness symptoms, vestibulo-vegetative instability were noted in workers of vibration professions. Impaired visual function is manifested by the narrowing and loss of certain areas of the visual fields, a decrease in visual acuity, sometimes up to 40%, subjectively - darkening in the eyes. Under the influence of general vibrations, a decrease in pain, tactile and vibration sensitivity is noted. A jerky vibration is especially dangerous, causing microtrauma of various tissues with subsequent reactive changes. General low-frequency vibration affects metabolic processes, manifested by changes in carbohydrate, protein, enzymatic, vitamin and cholesterol metabolism, and blood biochemical parameters.

Vibration sickness from the effects of general vibration and shocks is recorded in transport drivers and operators of transport and technological machines and units, in factories of reinforced concrete products. Changes in the lumbosacral spine are characteristic of car drivers, tractor drivers, bulldozer drivers, and excavator drivers exposed to low-frequency and jerky vibrations. Workers often complain of pain in the lower back, limbs, in the stomach, lack of appetite, insomnia, irritability, and rapid fatigue. In general, the picture of the effect of general low- and medium-frequency vibrations is expressed by general autonomic disorders with peripheral disorders, mainly in the limbs, a decrease in vascular tone and sensitivity.

The scourge of modern production, especially mechanical engineering, is local vibration. Mostly people working with hand-held power tools are exposed to local vibration. Local vibration causes spasms of the vessels of the hand, forearms, disrupting the supply of blood to the extremities. At the same time, vibrations act on nerve endings, muscle and bone tissues, cause a decrease in skin sensitivity, salt deposition in the joints of the fingers, deforming and reducing the mobility of the joints.

Oscillations of low frequencies cause a sharp decrease in capillary tone, and high frequencies cause vasospasm.

The timing of the development of peripheral disorders depends not so much on the level as on the dose (equivalent level) of vibration during the work shift. The time of continuous contact with vibration and the total time of exposure to vibration per shift are of primary importance. In molders, drillers, sharpeners, straighteners with a medium-frequency spectrum of vibrations, the disease develops after 8 - 10 years of work. Maintenance of a percussion instrument (riveting, stubbing), generating a vibration of the mid-frequency range (30 - 125 Hz), leads to the development of vascular, neuromuscular, osteoarticular and other disorders in 12 - 15 years. With local exposure to low-frequency vibration, especially with significant physical stress, workers complain of aching, breaking, pulling pains in the upper limbs, often at night. One of the persistent symptoms of local and general exposure is sensitivity disorder. Vibration, pain and temperature sensitivity suffers most sharply.

The factors of the working environment that aggravate the harmful effects of vibration on the body include excessive muscular loads, unfavorable microclimatic conditions, especially low temperatures, high-intensity noise, psychoemotional stress. Cooling and wetting your hands significantly increases the risk of developing vibration disease by increasing vascular responses. With the combined action of noise and vibration, a mutual amplification of the effect is observed as a result of its summation, and possibly also potentiation.

Long-term systematic exposure to vibration leads to the development of vibration disease, which is included in the list of occupational diseases. This disease is diagnosed, as a rule, in industrial workers. In populated areas, vibration disease is not recorded, despite the presence of many sources of vibration (ground and underground transport, industrial sources, etc.). Persons exposed to environmental vibrations are more likely to suffer from cardiovascular and nervous diseases and usually present many general complaints of a somatic nature.

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Vibration is one of the factors that high biological activity... The severity of response reactions is mainly due to the power of the energy impact and the biomechanical properties of the human body as a complex oscillatory system. Oscillatory process power in the contact zone and the time of this contact are the main parameters that determine the development of vibration pathologies, the structure of which depends on the frequency and amplitude of vibrations, the duration of exposure, the place of application and direction of the axis of the vibration effect, the damping properties of tissues, resonance phenomena and other conditions.

There is no linear relationship between the response of the body and the level of the impacting vibration. The reason for this phenomenon is seen in resonance effect... With an increase in vibration frequencies of more than 0.7 Hz, resonant vibrations in human organs are possible. The resonance of the human body, of its individual organs occurs under the influence of external forces when the natural frequencies of vibrations of internal organs coincide with the frequencies of external forces. The resonance area for the head in a sitting position with vertical vibrations is located in the zone between 20 - 30 Hz, with horizontal vibrations - 1.5 - 2 Hz.

The resonance is of particular importance in relation to the organ of vision. The visual disturbance manifests itself in the frequency range between 60 and 90 Hz, which corresponds to the resonance of the eyeballs... For organs located in the chest and abdominal cavity, the resonant frequencies are 3 - 3.5 Hz. For the whole body in a sitting position, resonance occurs at frequencies of 4 - 6 Hz.

Long-term systematic exposure to vibration leads to the development vibrational illness, which is included in the list of occupational diseases. This disease is diagnosed, as a rule, in industrial workers. In populated areas, vibration disease is not recorded, despite the presence of many sources of vibration (ground and underground transport, industrial sources, etc.).

Vibrations transmitted from a vibrating surface to the human body irritate numerous nerve endings in the walls of blood vessels, muscle and other tissues. The response impulses lead to violations of the normal functional state some internal organs and systems, and primarily peripheral nerves and blood vessels, causing them to contract. The nerve endings themselves, especially the skin ones, also undergo changes - they become less susceptible to irritation. All this manifests itself in the form of causeless pain in the hands, especially at night, numbness, a feeling of "creeping", sudden whitening of the fingers, a decrease in all types of skin sensitivity (pain, temperature, tactile). All this complex of symptoms characteristic of vibration exposure, received the name of vibration disease. Patients with vibration sickness usually complain of muscle weakness and fatigue. In addition to this, in women from exposure to vibration, violations of the functional state of the genital area often appear.

Development vibration sickness and. other unfavorable phenomena depends mainly on the spectral composition of vibration: the higher the vibration frequency and the more amplitude and speed of oscillations, the greater the danger is vibration in relation to the timing of development and the severity of vibration disease.

Vibration pathology is in second place (after dust) among occupational diseases. Considering health disorders during vibration exposure, it should be noted that the frequency of diseases is determined by the magnitude of the dose, and the features of clinical manifestations are formed under the influence of the vibration spectrum. There are three types of vibration pathology from the effects of general, local and jerky vibrations.

When the general vibration acts on the body, the nervous system suffers primarily and analyzers: vestibular, visual, tactile... Vibration is a specific irritant for the vestibular analyzer, with linear accelerations for the otolith apparatus located in the vestibule sacs, and angular accelerations for the semicircular canals of the inner ear.

Dizziness, movement coordination disorder, motion sickness symptoms, vestibulo-vegetative instability were noted in workers of vibration professions. Impaired visual function is manifested by the narrowing and loss of certain areas of the visual fields, a decrease in visual acuity, sometimes up to 40%, subjectively - darkening in the eyes. Under the influence of general vibrations, a decrease in pain, tactile and vibration sensitivity is noted. A jerky vibration is especially dangerous, causing microtrauma of various tissues with subsequent reactive changes. General low-frequency vibration affects metabolic processes, manifested by changes in carbohydrate, protein, enzymatic, vitamin and cholesterol metabolism, and blood biochemical parameters.

Vibration sickness from the effects of general vibration and shocks is recorded in transport drivers and operators of transport and technological machines and units, in factories of reinforced concrete products. For car drivers, tractor drivers, bulldozer drivers, excavator drivers exposed to low frequency and jerky vibrations, changes in the lumbosacral spine are characteristic. Workers often complain of pain in the lower back, limbs, in the stomach, lack of appetite, insomnia, irritability, and rapid fatigue. In general, the picture of the effect of general low- and medium-frequency vibrations is expressed by general autonomic disorders with peripheral disorders, mainly in the limbs, a decrease in vascular tone and sensitivity.

Oscillations of low frequencies cause a sharp decrease in capillary tone, and high frequencies cause vasospasm.

Measures to combat noise and vibration are similar in many ways.

First of all, it is necessary to pay attention to the technological process and equipment, if possible, replace operations accompanied by noise or vibration with others.

An important role in the fight against noise and vibration is played by architectural and construction and planning solutions in the design and construction of industrial buildings. First of all, it is necessary to remove the most noisy and vibrating equipment outside the production premises where the workers are located; if this equipment requires constant or frequent periodic monitoring, soundproof booths or rooms for service personnel are equipped at the site of its placement.

In order to prevent the adverse effects of local and general vibration, workers must use personal protective equipment. When exposed to local vibration (often on the hands), handles and other vibrating parts of machines and tools (for example, a pneumatic hammer) in contact with the worker's body are covered with rubber or other soft material. Gloves also play a vibration-damping role.

conclusions

Noise and vibration are united by a common principle of their formation: they are all the result of vibrations of bodies transmitted directly or through gaseous, liquid and solid media. They differ from each other only in the frequency of these vibrations and in the different perception of them by a person.

Oscillations with a frequency from 20 to 20,000 Hz (hertz is a unit of frequency equal to one oscillation per second) transmitted through a gaseous medium are called sounds and are perceived by the human hearing organs as sounds; a disorderly combination of such sounds constitutes noise.

Vibrations of solids or transmitted through solids (machines, building structures, etc.) are called vibration. Vibration is perceived by a person as a shock at a general vibration with a frequency of 1 to 100 Hz, and at a local (local) - from 10 to 1000 Hz (for example, when working with a vibration instrument).

There are no clear boundaries between noise and vibration, therefore, at the border frequencies, a person is usually affected by the above two factors.

The human body as an oscillatory system. Vibrations are called vibrations of a rigid body about a position of equilibrium (rest). In this case, either the whole body vibrates in space as a whole, without changing its shape, or the particles that make up the body vibrate, changing the shape of the outer surface, with the formation of alternating bulges and depressions. Both types of vibrations can exist both separately and together.

Vibration as a physical phenomenon is based on the oscillatory process and the wave motion of its propagation in the environment. With the propagation of vibrations, the amount of vibrational energy transmitted by the vibrating surface to the human body should depend on the size of the contact area, the parameters and duration of exposure to vibrations and the mechanical resistance of the body to the action of vibrations. Spreading from the excitation zone through the human body, vibrations cause alternating stresses in the tissues of the body (compression, stretching, shear, torsion or bending). Changes in stress are captured by a variety of receptors located in tissues not only in the zone of contact with a vibrating surface, but also in the area of ​​vibration propagation, and the vibrational energy transmitted to a person is partly spent on friction in tissues and joints, turning into thermal energy, and partly transformed by receptors into energy biochemical and bioelectric processes that arise in the body and determine the nature, direction and magnitude of the reflex response of the whole organism to an external stimulus. The formation of this response is influenced by the accompanying vibrations of unfavorable factors - an uncomfortable working posture, statistical stress, an uncomfortable microclimate, intense noise, etc.

Systematic prolonged exposure to vibration, significantly exceeding the thresholds of its perception, can cause persistent disturbances in normal physiological functions in the body.

Vibrations are perceived by different organs and parts of the body. So, with low-frequency (up to 15 Hz) vibrations, translational vibrations are perceived by the otolith, and rotational - by the vestibular apparatus of the inner ear. Upon contact with the vibration of a solid body, the perception of vibration is carried out by the nerve endings of the skin.

A person senses vibrations from a fraction of a hertz to about 80 Hz, and vibrations of high frequencies are perceived like ultrasonic vibrations, causing a thermal sensation.

The source of vibration is varied. The source of vibration in residential and public buildings is engineering and sanitary equipment. Vibration sources can also be industrial installations, vehicles (metro, railway), which create large dynamic loads during operation, which cause the propagation of vibration in the soil and building structures of buildings. These vibrations are also often the cause of noise in buildings.

In contrast to the work environment, vibration in living quarters can act around the clock, causing irritation, disrupting rest and sleep.

The influence of vibrations on the human body. Vibration disease. Vibrations of a power tool, technological equipment or means of transport always affect a person in any specific conditions: working posture and static stress of the body; microclimate and dust-gas composition of the air; associated noise or any other factors. They are characterized by a specific method and mode of exposure during the working day. Therefore, the features of the manifestation of the biological effect of vibrations are also influenced by these factors.

The severity of violations of physiological functions that can be observed as a result of prolonged repeated action and the individual characteristics of the organism and, in particular, the state of the nervous processes - their strength, balance and mobility.

According to the method of exposure, vibrations are conventionally divided into general ones - acting through the supporting surfaces of the body in a standing, sitting or lying position, and local ones - acting through the palmar surfaces of the hands.

Under the action of vibration on a person, changes are noted on the part of many organs and systems of varying the severity of individual symptoms. In some cases, vascular disorders are more pronounced, in others - dysfunctions of the musculoskeletal system.

Significant changes are found in the autonomic nervous system. When exposed to vibration of a mechanized tool on the human body, the following violations of physiological functions occur. First of all, vibration sensitivity is disturbed. The vast majority of people with vibration-hazardous professions have increased vibration sensitivity thresholds. Vibration with a low frequency up to 30 Hz, mainly causes pain sensitivity disorders. Its changes begin at the tips of the fingers, cover the entire hand and the lower part of the forearm, like a short or long glove.

With the simultaneous action of vibration and noise among persons with a long experience, cases of a pronounced form of occupational hearing loss can be observed.

With local vibration, first of all, the regulation of the tone of peripheral blood vessels suffers, and the plasticity of the lymphatic bed is disturbed. Direct mechanical and reflex stimulation of vascular smooth muscle cells lead to spasms.

With local vibration, pathological changes occur in the neuromuscular apparatus: electrical excitability and lability of muscles and peripheral nerves decrease, bioelectric activity in the resting muscle increases, motor coordination is impaired. The strength, tone and endurance of muscles decrease, foci of seals, painful strands appear in the muscle tissue, and atrophy develops.

General vibration causes similar disorders in the entire motor sphere of the body, caused by both mechanical trauma and reflex changes in the trophism of muscle tissue, peripheral nerve endings and trunks.

When exposed to general vibration, the central nervous system is particularly affected. In the cerebral cortex, inhibitory processes predominate, normal cortical-subcortical relationships are disrupted, and autonomic dysfunctions occur. As a result, the general physical and mental state of the body worsens, which can be expressed in fatigue, depression or irritability, headaches and other nervous disorders up to persistent neuroses.

Vibration can affect all sensory systems. With local vibration, there is a decrease in temperature, pain, vibration, tactile sensitivity. With general vibration, visual acuity decreases, the field of vision decreases, the photosensitivity of the eye decreases, the blind spot increases; the perception of sounds worsens, the activity of the vestibular apparatus is disrupted. Hemorrhages are found in the tympanic cavity of the middle ear, semicircular canals. Concussion can occur under the influence of vibrations.

Due to the stressful nature of the action of vibration, the entire system of neurohumoral regulation is disturbed, as well as metabolic processes, the function of the digestive system, liver, kidneys, and genitals. As a mechanical factor, vibration causes a disturbance in the hydrodynamic balance in tissues and internal organs, an increase in the total energy consumption of the body with corresponding shifts in oxidative processes, disturbances from the respiratory and vocal apparatus, trauma due to displacements of internal organs and systems.

With prolonged exposure to vibration, a person develops vibration disease. Vibration disease is an occupational disease caused by vibration. It was first described by Loriga in 1911. The main factor leading to the development of the disease is vibration. The severity and time of development of the disease is determined by the area of ​​parts and the amount of vibrational energy transmitted to the entire human body or a limited area of ​​it, as well as the factors accompanying the development of vibration disease: a return blow from a hand tool, forced body position, cooling, noise.

At the heart of vibration disease is a complex mechanism of nervous and reflex disorders that lead to the development of foci of stagnant excitation and to persistent subsequent changes both in the receptor apparatus and in various parts of the central nervous system. An essential role in the pathogenesis of vibration disease is also played by specific and nonspecific reactions, reflecting the adaptive-compensatory processes of the body. It is believed that vibration disease is a process in which a spasm of small and larger vessels is observed. Possible trophic changes in the skin, nails up to the development of gangrene of the fingers of the hands and feet. There is atrophy of the muscles of the arms and shoulder girdle. In the spinal cord - dystrophic changes in nerve cells, minor hemorrhages, necrosis. In the osteoarticular apparatus of the upper limb - aseptic necrosis of the articular parts of the bones, which is a reflection of atrophic, dystrophic, necrotic and regenerative processes in cartilage, articular capsules, bones. In the bone tissue, there are foci of compaction with the deposition of lime in them. Most often, this pathology is found in the heads of the metacarpal bones. In muscle tendons, lime deposits and bone formation are sometimes noted.

Vibration disease caused by exposure to local vibration is complex in terms of clinical symptoms. The disease develops gradually. The patient complains of pain in the hands, sometimes cramps in the fingers, increased sensitivity to cold, irritability, insomnia. The leading place is occupied by vascular syndrome, accompanied by bouts of whitening of the fingers after general or local cooling of the body, as well as disturbances in sensitivity - vibration, pain, temperature. Vascular disorders appear earlier in the capillary circulation. There is swelling of the fingers and their deformation, a decrease in muscle strength and muscle tone.

Vibration disease caused by general vibration is marked by significant changes in the central nervous system. Functional disorders of the digestive glands, gastritis, metabolic disorders are noted.

There are four stages of vibration disease: Stage I - initial, low-symptom, complaints of mild pain in the hands with mild sensory disturbances at the fingertips predominate; Stage II - moderately pronounced, there is a decrease in temperature and sensitivity of the skin, narrowing of the capillaries, there are deviations in the function of the central nervous system, the phenomena are reversible; Stage III - severe disorders, sensitivity disorder, noticeable shifts in the functional state of the central nervous system, changes are persistent and slowly respond to treatment; Stage IU - the symptoms are pronounced, vascular disorders in the arms and legs, disorders of the coronary and cerebral vessels, the condition is persistent, hardly reversible.

Treatment is based on complex therapy in the form of vasodilators and the use of physiotherapeutic methods.

Prevention of adverse effects of vibration. Reducing the harmful effects of vibration can be achieved in the following main ways:

I. Technical measures:

· Reduction of vibration at the source of their formation by constructive and technological measures (change of the working cycle diagram, use of materials with high internal friction;

· Reduction of vibration along the path of propagation can be achieved by means of vibration isolation and vibration absorption: the use of spring and rubber shock absorbers, gaskets, lining of handles and other contact points with vibration-absorbing materials, the device of vibration-insulating bushings;

· Fight against accompanying unfavorable factors of the production sphere. So, to protect the organ of hearing from noise when working with vibrating equipment, it is recommended to have individual anti-noise; these include internal earbuds, ear muffs and helmets.

II. Work and rest mode.

III. Treatment and prophylactic measures.

Vibrotherapy as a method of physiotherapy. Vibrotherapy is a method of physiotherapy, which consists in the impact of mechanical vibrations of low frequency and amplitude on various parts of the body or the whole body of the patient. The fact that vibration has healing properties has been known for a long time. It was used explicitly and implicitly: cart riding, horseback riding, acoustic exposure, rhythmic dances. These observations and centuries of experience have led to the need for the development of special devices and methods that make it possible to purposefully use vibration for therapeutic effects either of the whole person, or on individual parts of his body, or localized on specific areas of the skin.

There are two approaches to using vibration as a diagnostic and therapeutic agent. The first, which has become traditional, is the effect of vibration on diseased parts of the body or the entire body as a whole. The second is in which vibration excitation is addressed to local skin areas.

Vibration therapy is carried out in the simplest case by rhythmic tapping of the patient's body with the palms of a masseur or by using mechanical vibration devices of various designs.

Mechanical vibrations during vibration therapy can be transmitted from their source and through the bath water in which the patient is placed. Vibration baths are carried out every other day, their duration is set depending on the disease and the localization of exposure from 2-3 to 12-30 minutes. The dosage of the effect is regulated according to the patient's sensation, depending on the functional state of the nervous system, body temperature and, to a large extent, on which part of the bodies the mechanical stimulation is directed to. In the area of ​​exposure, there is a decrease in pain or various degrees of "numbness" depending on the applied intensity of the stimulus and on the nature of the disease.

In the mechanism of action of vibrotherapy, the most important is the transmission of a locally applied stimulus from baroreceptors through conductive fibers to the posterior columns of the spinal cord and from here to the thalamus and cerebral cortex. The irritation spreads within the corresponding metamere of the body, including its constituent internal organs.

Vibration therapy can have anesthetic, anti-inflammatory effect, stimulate metabolic processes in muscle tissue, and improve peripheral blood circulation.

Indications for recovery: consequences of injuries of the joints and spine, nerve diseases, chronic diseases of the joints and spine (osteochondrosis), chronic gastritis, cholecystitis, constipation, bronchial asthma, chronic inflammatory diseases of the female genital organs.

Contraindications to recovery: pronounced forms of neuroses, pronounced dysfunction of the endocrine system, thrombophlebitis, pregnancy, condition after a recent (up to 1 year) trauma of the brain and spinal cord.

Lecture number 20

Water and health

Water content in the human body. The body of an adult contains about 65% water. So, in men, about 61% of body weight is water, and in women - 54%. The difference is due to the high amount of fat in the woman's body. It should also be noted that the younger the body, the greater the specific gravity of water in its composition. So, a 6-week-old embryo contains 97.5% of water, in a newborn body - 70-83%, in old age it decreases to 50%. Water in the body can be free, constituting the basis of the intracellular fluid; constitutional, part of the molecules of proteins, fats and carbohydrates; bound, which is part of colloidal systems. Water is involved in the regulation of body temperature and blood formation.

Most of the water is inside the cells - 71%, outside the cells - 19%, in the circulating blood, lymph, cerebrospinal fluid and other fluids - 10% of the total amount of water in the body. The smallest amount of water is associated with proteins - no more than 4%. The amount of water in the body depends on the amount of fat: the more fat, the less water.

Water makes up about 22% -30% adipose tissue, 55% cartilage, 70% liver, 70% brain, 72% skin, 76% muscle, 76% spleen, 78% pancreas, 79% heart, 79% lung, 80% connective tissue, 83% of the kidneys in relation to the mass of the organ. Plasma contains 92% water, and digestive juices contain 98-99% and more.

Water in the body performs the following functions:

· In the aquatic environment, the digestion process takes place;

· In aqueous solutions and with the participation of water, metabolism, hematopoiesis occurs;

· Without water, absorption processes and all chemical and enzymatic processes are impossible;

· With the help of water, food products are transferred in the body, as well as their assimilation;

· Water is involved in thermoregulation processes;

· Poisonous toxins are excreted from the body with water;

· Water is a versatile solvent.

The constancy of the volume of fluids in the internal environment of the body is ensured by water-salt metabolism. Water entering the body from the stomach and intestines enters the bloodstream and is carried throughout the body. In the body, water is distributed between different liquid phases in accordance with the concentration of osmotically active substances in them.

Daily balance of water in the body. Drinking regime. In the human body, in the course of evolution, a complex mechanism has been developed that ensures normal water balance - the amount of consumed water should be equal to its consumption. The water balance in humans is calculated based on the daily consumption of water, as well as its excretion from the body. A person receives an average of 2.5 liters of water per day: 1.2 liters - due to the liquid he drinks, 1 liter - together with foodstuffs that contain water, 0.3 liters of water is formed in the body itself in the process of metabolism - this is the so-called endogenous water. The same amount of fluid in 24 hours should be excreted from the body.

An adult needs 2.5-3 liters of water per day - in the composition of food and drinking, because approximately this amount of water is lost to the external environment. If the temperature of the external environment is equal to the temperature of the human body, then an adult evaporates 4.5 liters of water every day.

The need for water varies significantly depending on the ambient temperature, on the nature of the diet, and in particular on the salt content of the food. For example, when working in hot climates, the total daily requirement for water in food and drink increases to 10 liters.

In addition, water is formed in the body itself during the oxidation of nutrients. It is found in large quantities in some foods, such as vegetables, berries, and fruits. With complete oxidation, water is formed per 100 g of the substance: during the oxidation of protein - 41 cm 3, starch - 55 cm 3, fat - 107 cm 3.

For every 420 J released during the splitting of organic substances, 12 cm 3 of water is formed, and about 300 cm 3 per day. On average, an adult's body receives 1200 cm 3 of drinking water per day, and 1000 cm 3 of the food contained in food. A day from the body of an adult is excreted with urine about 1.5 liters, with feces - 100-200 cm 3, through the skin - 500 cm 3 and through the lungs - 350-400 cm 3. This keeps the water balance.

With a lack of water in the body, a feeling of thirst appears, which is expressed by a peculiar sensation of dryness in the mouth and pharynx. The center regulating water exchange is located in the brain stem. The main cause of thirst is a violation of the optimal ratio between water, salts and organic substances in the blood, as a result of which the osmotic pressure of the body fluid rises.

Drinking regimen- rational order of water consumption. A correctly established drinking regime ensures a normal water-salt balance and creates favorable conditions for the vital activity of the body. Indiscriminate, excessive drinking impairs digestion, creates an additional load on the cardiovascular system and kidneys, leads to an increase in the excretion of a number of substances valuable for the body (for example, table salt) through the kidneys and sweat glands. Even a temporary load of water disrupts the working conditions of the muscles, leads to rapid fatigue, and sometimes causes convulsions. Insufficient water intake also disrupts the normal vital activity of the body: body weight decreases, blood viscosity increases, body temperature rises, pulse and respiration become more frequent, thirst and a feeling of nausea appear, and working capacity decreases.

The minimum amount of water required to maintain the water-salt balance during the day (drinking rate) depends on climatic conditions, as well as the nature and severity of the work performed. For example, for temperate latitudes, the amount of water introduced with drinking and food with minimal physical activity is 2.5 liters per day, with physical work of medium severity up to 4 liters, in the climate of Central Asia with a minimum physical activity of 3.5 liters, with physical work of medium severity up to 5 liters, during heavy work in the open air up to 6.5 liters.

It is especially important to observe the correct drinking regime in conditions that cause large losses of fluid in the body, which often occurs in hot climates, when working in hot workshops, during prolonged and significant physical exertion (for example, during training and in competitions, mountain climbing). Residents of areas with hot climates are advised to completely quench their thirst only after satiety and strictly limit fluid intake in between meals. To quench thirst, use tea that increases salivation and eliminates dry mouth, add fruit and vegetable juices or extracts to the water. In hot shops they drink carbonated water or dried fruit decoctions. The drinking regimen of athletes provides for thirst quenching after exercise. When mountain climbing, it is recommended to quench your thirst only during long breaks. With significant weight loss associated with high physical activity (after workouts, sports competitions, steam baths), it is recommended to drink in fractional portions.

The consequences of a lack and excess of water in the human body. Under certain conditions, both a lack and an excess of water in the body can be the main reason for the violation of certain functions up to the development of chronic diseases. Lack of water in the body is difficult for humans to tolerate.

A decrease in the total water content in the body, when its losses exceed the intake and formation, is called dehydration (negative water balance). According to the mechanism of development, dehydration of the body can be caused by excessive excretion of water with insufficient replacement, loss of water due to primary loss of sodium, restriction or termination of water intake.

The body can lose a significant amount of water through the intestines (with diarrhea, laxatives), stomach (with profuse vomiting), kidneys (diabetes, action of diuretics), skin (increased sweating), lungs (with increased ventilation in dry air) , as a result of blood loss, with extensive burns, wounds. When performing work, the greatest loss of water with sweat is observed in conditions of overheating of the body. When climbing high mountains, increased water loss is facilitated by increased sweating due to physical activity and its rapid evaporation; at altitude, a lot of water is also lost through the lungs due to an increase in ventilation and dry air. Water loss associated with prolonged carbohydrate-free diets can be the cause of dehydration. With a loss of water in an amount of less than 2% of the body weight, thirst appears, with a loss of 6-8% - a semi-faint state, 10% - hallucinations and difficulty swallowing, with a deficit of more than 12%, death occurs.

Clinically, dehydration is manifested by a decrease in body weight, intense thirst, loss of appetite, and nausea. The mucous membrane becomes flabby, wrinkled, loses elasticity, the fold of the abdominal skin does not smooth out for a long time. Blood and intraocular pressure decreases, the pulse is rapid and weakened. Weakness increases, there is a headache, dizziness, gait instability, coordination of movements is impaired. Weakened muscle strength, attention, decreased performance. Sometimes the body temperature rises. With an increase in the clinical picture, a further decrease in body weight occurs; eyeballs sink, facial features sharpen, vision and hearing weaken, swallowing is severely difficult; circulatory failure increases, urination becomes painful, the psyche is disturbed. With severe dehydration, the feeling of thirst may be lost. If a person is in relative rest and in a moderate ambient temperature, he can live without water for a week (without food for about a month), and in conditions of high temperature - only three days.

Excess water is a common form of disturbance in water-salt metabolism. It manifests itself mainly in the form of edema and dropsy of various origins. With an excess of water, its content in blood and plasma increases, as a result of which the hematocrit index decreases. Hydration of cells is observed. The body weight is increasing. The appearance of nausea, vomiting is characteristic. The mucous membranes are moist. Apathy, drowsiness, headache, muscle twitching, convulsions, impaired coordination of movements, muscle weakness testify to the hydration of brain cells. Excess water overloads the cardiovascular system, causing exhausting sweating, accompanied by the loss of salts and water-soluble vitamins, weakens the body. With an excess of water, there is profuse salivation, a drop in temperature, and increased urine output.

Indications and methods of using mineral waters. Mineral springs of the Republic of Belarus. Mineral waters - underground (sometimes surface) waters with an increased content (more than 1 g / l) of mineral salts and gases, possessing physicochemical properties (chemical composition, temperature, radioactivity), allowing them to be used for medicinal purposes. Some mineral waters are of industrial importance. By mineralization, they are distinguished: low-mineralized (1-2 g / l), low (2-5 g / l), medium (5-15 g / l), high (15-30 g / l) mineralization, brine (35-150 g / l) and strongly brine (above 150 g / l) mineral waters. According to the ionic composition, mineral waters are divided into chloride (Cl -), hydrocarbonate (HCO 3 -), sulfate (SO 4 2-), sodium (Na +), calcium (Ca 2+), magnesium (Mg 2+). According to the presence of gases and specific elements, they are distinguished: carbon dioxide, sulfide (hydrogen sulfide), nitrogen, bromide, iodide, ferrous, arsenic, silicon, radioactive (radon) mineral waters. They are distinguished by temperature: cold (up to 10 0 C), warm (20-37 0 C), hot (thermal, 37-42 0 C) and very hot (high-thermal, from 42 0 C and above) mineral waters.

The use of natural mineral waters is one of the oldest methods of treating a number of diseases. It was known to the ancient medieval doctors of Europe and the Arab East. The first mentions of their medicinal properties are in the writings of the Greek physician Hippocrates (IU century BC), where some information about the properties of salt and sea water is given. In the CUI century, the experience gained by that time in the treatment of mineral waters was summarized by the Italian physician G. Fillopia in the book "Seven books about dark waters". In the CUI-CUII centuries, the construction, equipment and operation of resort areas with various mineral waters began to be more widely considered. In Russia, state measures for the exploration of mineral waters and their exploitation for medicinal purposes were initiated by Peter I.

Under the curative mineral waters it is customary to understand underground waters containing in high concentrations various mineral (less often organic) components and gases or possessing any special physical properties (radioactivity, high temperature), due to this mineral waters have a therapeutic effect on the human body when externally or internal use. Medicinal waters include waters exceeding 2 g / l or with a lower salt content in the presence of pharmacologically active microcomponents. In medicinal waters, mineralization reaches 2000 mg / l, carbon dioxide is 500 mg / l, hydrogen sulfide - 10 mg / l, arsenic - 0.7 mg / l, iron - 20 mg / l, bromine - 25 mg / l, iodine - 5 mg / l, silicic acid - 50 mg / l and radon - (5 nCi / l).

According to its medicinal properties, mineral waters are divided into 8 balneological groups: without "specific" components and properties, carbonic, sulfide (hydrogen sulfide), arsenic, ferrous, iodine-bromine with a high content of organic matter, siliceous thermal and radon.

Depending on the mineralization, mineral waters are used for both indoor and outdoor use. Their therapeutic effect on the body is due to a complex of substances dissolved in water, physicochemical properties, as well as mechanical and chemical effects. With the internal use of mineral waters, the physiological effect and therapeutic effect depends on the amount of water taken, its temperature, mineralization, chemical composition, time of intake in relation to food intake, on the functional state of the digestive system. This combines the various effects of the use of mineral waters. So, chloride and sulfate waters of high mineralization (more than 15 g / l) can irritate the gastric mucosa and cause exacerbation of diseases. The laxative effect of sulphate sodium and magnesium waters begins when the content of sulphate ions in them is more than 2.5 g / l.

Mineral water with the same total mineralization, different chemical compositions, affects the human body in different ways. For example, sodium chloride waters have a beneficial effect on the digestive organs; calcium chloride promotes anti-inflammatory processes and has a positive effect on the nervous system; magnesium chloride help to dilate blood vessels; sulfate waters, mainly choleretic and laxatives. Sodium bicarbonate (like "Borjomi") reduce acidity.

The therapeutic effect of sodium chloride waters when applied externally (baths) is determined by thermal, chemical and gas components that improve the activity of the cardiovascular, nervous system, and enhance metabolic processes. These waters are also used for diseases of bones and joints.

Waters containing iodine and bromine are used for internal and external use. Iodine enhances the action of the endocrine glands. Bromine has a beneficial effect on the central nervous system, facilitates the work of the heart, and helps to lower blood pressure. Iodine-bromine baths are effective in the treatment of functional diseases of the nervous system, atherosclerosis, skin and other diseases.

Ferrous mineral waters are used as drinking waters, which have a beneficial effect on the processes of hematopoiesis. They are used in the treatment of iron deficiency anemias. Arsenic mineral waters are more commonly used for oral administration. They are prescribed for exhaustion and anemia. Siliceous thermal waters treat chronic gastritis, colitis, liver diseases, metabolism, while sulphide mineral waters treat diseases of the cardiovascular system, chronic inflammatory diseases of bones, joints and skin diseases. Radon baths are prescribed for a number of diseases of the nervous system and cardiovascular system, organs of movement, and skin.

More than 25 mineral water deposits have been explored in Belarus, which can produce 4.3 thousand m 3 of water per day (Table 4). Of these, only about 10% of the resources of the identified 11 types of mineral waters are still being used. Mineral waters of the republic with salinity from 1.7 to 4.40 g / l are mostly cold (10-15 0 С), with the exception of deep brines with temperatures up to 89 0 С, nitrogen non-carbonated (gas saturation up to 35 g / l), in most cases without specific components. In terms of chemical composition, they are sulfate calcium-magnesium, chloride sodium, chloride-sulfate sodium-calcium, chloride-sulfate sodium, chloride sodium and chloride calcium with a high content of hydrogen sulfide, bromine, iodine. The most common are sodium chloride waters. They were explored on Lake Naroch, in Bobruisk, in the Gomel region (sanatorium "Vasilyevka"), in the Brest region (sanatorium "Berestye").