a) General vibration is the vibration of the whole body transmitted from the workplace.
Studies of the characteristics of the mechanical effect of general vibration have shown the following. The human body, due to the presence of soft tissues, bones, joints, and internal organs, is a complex oscillatory system, the mechanical response of which depends on the parameters of the vibration effect. At frequencies below 2 Hz, the body responds to general vibration as a rigid mass. At higher frequencies, the body reacts as an oscillatory system with one or several degrees of freedom, which manifests itself in a resonant amplification of oscillations at individual frequencies. For a sitting person, the resonance is at frequencies of 4-6 Hz; in a standing position, 2 resonance peaks were found: at 5 and 12 Hz. The natural frequency of vibrations of the pelvis and back is 5 Hz, and the chest-abdomen system is 3 Hz.
With prolonged exposure to general vibration, mechanical damage to tissues, organs and various body systems is possible (especially when there is a resonance of the body’s own vibrations and external influences). This is why mechanical exposure to vibration often leads to various pathological reactions in truck drivers, tractor drivers, pilots, etc.
b) Local vibration - affects individual parts of the body (upper limbs, shoulder girdle, heart vessels).
When studying the characteristics of the mechanical effect of local vibration on the human body, it was found that vibration applied to any area is generated throughout the body. The propagation zone when exposed to low frequency vibration is larger, since the absorption of vibrational energy in the structures of the body is less. With the systematic vibration effect of low-frequency vibrations, the muscles are primarily affected, and the more strongly the more muscle tension required to work with the tool.
Workers who use manual machines for a long time experience various changes in the muscles of the shoulder girdle, arms and hands. This is due both to direct muscle trauma and to dysregulation due to damage to the central nervous system. Under the influence of local vibration, osteoarticular changes also occur, especially in the elbow and wrist joints, and in the small joints of the hands. Osteoarticular deformations occur due to a violation of the dispersion of tissue colloids, as a result of which the bone loses the ability to bind calcium salts.
The effect of vibration on the nervous system causes an imbalance of nervous processes in the direction of predominance of excitation, and then inhibition. The cortical parts of the brain are sensitive to vibration. Particularly sensitive to the effects of local vibration are the parts of the sympathetic nervous system that regulate the tone of peripheral vessels.
Examinations of workers of various professional groups: choppers, riveters, grinders, drillers - made it possible to establish that spasm of the capillaries more often occurs with vibrations with a frequency of over 35 Hz, and at lower frequencies the capillaries usually experience an atonic state. In patients exposed to local vibration, changes are primarily observed in the rheograms of the fingers and hand, and due to the general impact of vibration, changes are observed in the rheograms of the feet and rheoencephalograms. In many patients, changes in ECG, pulse rate, blood pressure, and cerebral circulation parameters were observed.
The effect of vibration on the vestibular apparatus leads to the emergence of a variety of vestibulosomatic and vestibulo-vegetative reactions. The impact on vision, especially at resonant frequencies of 20-40 and 60-90 Hz, increases the amplitude of vibrations of the eyeball and worsens visual acuity, reduces color sensitivity, and narrows the boundaries of the visual field.
The normalized frequency range for technological vibration and for vibration at workplaces of knowledge workers is established in the form of octave bands with geometric mean frequencies:
For local vibration -2; 4;8 ; 16; 31.5; 63; 125; 250; 500; 1000 Hz;
For general vibration - 2; 4; 8; 16; 31.5; 63 Hz.
The time of exposure to vibration is assumed to be equal to the duration of continuous or total exposure measured in minutes or hours.
The standardized indicators of the vibration load on the operator at workplaces during the work process are single-numeric parameters (frequency-corrected value of the controlled parameter, vibration dose, equivalent adjusted value of the controlled parameter) or vibration spectrum (Appendices 1-4).
The vibration load on the operator is standardized for each direction of vibration.
For local vibration, the standard vibration load on the operator ensures the absence of vibration sickness, which corresponds to the “safety” criterion.
For general vibration, the norms of vibration load on the operator are established for vibration categories and the corresponding evaluation criteria according to Table 1.
| Vibration categories | criteria for evaluation | Characteristics of working conditions |
| safety | Transport vibration affecting operators of mobile self-propelled and trailed machines and vehicles when they move across terrain, agricultural backgrounds and roads, including during their construction | |
| limit of reduction in labor productivity | Transport and technological vibration affecting operators of machines with limited mobility moving only on specially prepared surfaces of production premises, industrial sites and mine workings | |
| 3 type "a" | limit of reduction in labor productivity | Technological vibration affecting operators of stationary machines and equipment and transmitted to workplaces that do not have sources of vibration |
| 3 type "" in" | comfort | Vibration in the workplaces of knowledge workers and non-manual workers |
The “safety” criterion means non-impairment of the operator’s health, assessed by objective indicators, taking into account the risk of occurrence of occupational diseases and pathologies provided for by the medical classification, and also excluding the possibility of traumatic or emergency situations arising due to exposure to vibration.
The criterion “margin of reduction in labor productivity” means maintaining the standard productivity of the operator, not decreasing due to the development of fatigue under the influence of vibration.
The “comfort” criterion means creating working conditions that provide the operator with a feeling of comfort in the complete absence of interfering vibration.
Methods and means of protection against vibration.
To protect against vibration, the following methods are used: reducing the vibration activity of machines; detuning from resonant frequencies; vibration damping; vibration isolation; vibration damping, as well as personal protective equipment. Reducing the vibration activity of machines (reducing Fm) is achieved by changing the technological process, using machines with such kinematic schemes in which dynamic processes caused by impacts, accelerations, etc. would be eliminated or extremely reduced, for example, replacing riveting with welding; good dynamic and static balancing of mechanisms, lubrication and cleanliness of processing of interacting surfaces; the use of kinematic gears of reduced vibration activity, for example, herringbone and helical gears instead of spur gears; replacing rolling bearings with plain bearings; the use of structural materials with increased internal friction.
Detuning from resonant frequencies involves changing the operating modes of the machine and, accordingly, the frequency of the disturbing vibration force; the natural frequency of vibration of the machine by changing the rigidity of the system, for example by installing stiffeners or changing the mass of the system (for example, by attaching additional masses to the machine).
Vibration damping is a method of reducing vibration by enhancing friction processes in a structure that dissipate vibrational energy as a result of its irreversible conversion into heat during deformations that occur in the materials from which the structure is made. Vibration damping is carried out by applying to the vibrating surfaces a layer of elastic-viscous materials that have large losses due to internal friction - soft coatings (rubber, PVC-9 foam, VD17-59 mastic, Anti-vibrite mastic) and hard ones (sheet plastics, glass insulation, waterproofing, aluminum sheets); the use of surface friction (for example, plates adjacent to each other, like springs); installation of special dampers.
Vibration damping (increasing the mass of the system) is carried out by installing the units on a massive foundation. Vibration damping is most effective at medium and high vibration frequencies. This method is widely used when installing heavy equipment (hammers, presses, fans, pumps, etc.).
Increasing the rigidity of the system, for example by installing stiffeners. This method is effective only at low vibration frequencies.
Vibration isolation consists of reducing the transmission of vibrations from the source to the protected object using devices placed between them. For vibration isolation, vibration-isolating supports such as elastic pads, springs, or a combination thereof are most often used. The effectiveness of vibration isolators is assessed by the transmission coefficient of the gearbox, equal to the ratio of the amplitude of vibration displacement, vibration velocity, vibration acceleration of the protected object, or the force acting on it to the corresponding parameter of the vibration source. Vibration isolation only reduces vibration when the gearbox< 1. Чем меньше КП, тем эффективнее виброизоляция.
Preventive measures to protect against vibrations include reducing them at the source of formation and along the path of distribution, as well as using personal protective equipment, carrying out sanitary and organizational measures.
Reducing vibration at the source of occurrence is achieved by changing the technological process with the manufacture of parts from nylon, rubber, textolite, timely implementation of preventive measures and lubrication operations; centering and balancing of parts; reducing gaps in joints. The transmission of vibrations to the base of the unit or the building structure is weakened by shielding, which is also a means of combating noise.
If collective protection methods do not produce results or are irrationally applied, then personal protective equipment is used. Anti-vibration gloves and special shoes are used as means of protection against vibration when working with power tools. Anti-vibration ankle boots have a multi-layer rubber sole.
The duration of work with a vibrating tool should not exceed 2/3 of the work shift. Operations are distributed among workers so that the duration of continuous vibration, including micro-pauses, does not exceed 15...20 minutes. It is recommended to take breaks of 20 minutes 1...2 hours after the start of the shift and 30 minutes 2 hours after lunch.
Vibration is a complex oscillatory process that occurs when the center of gravity of a body or system of bodies periodically shifts from the equilibrium position, as well as when the shape of the body that it had in a static position periodically changes.
The reason for the excitation of vibrations is the unbalanced force effects that occur during the operation of machines and units. Sources of vibrations are reciprocating moving systems (crank mechanisms, hand hammers, sealers, vibrating rammers, devices for packaging goods, etc.), as well as unbalanced rotating masses (electric and pneumatic grinding and cutting machines, cutting tools).
The main parameters of vibration occurring according to the sinusoidal law are: frequency, displacement amplitude, speed, acceleration, period of oscillation (the time during which one complete oscillation occurs).
Depending on the employee’s contact with vibrating equipment, there are: local(local) and general vibration (vibration of workplaces). Vibration affecting individual parts of the worker’s body is defined as local. Vibration of the workplace, affecting the entire body, is defined as general. In production conditions, local and general vibration often occurs simultaneously, which is called mixed vibration.
Based on the direction of action, vibration is divided into those acting along the axes of the orthogonal coordinate system X, Y, Z.
According to the source of its occurrence, general vibration is divided into:
1. On transport, which arises as a result of the movement of vehicles across terrain and roads.
2. Transport and technological, which occurs during the operation of machines performing a technological operation in a stationary position and when moving through a specially prepared part of the production premises or industrial site.
3. Technological, which occurs during the operation of stationary machines or is transmitted to workplaces that do not have sources of vibration. Generators of technological vibration are equipment: sawmills, woodworking, for the production of technological chips, metalworking, forging and pressing, as well as compressors, pumping units, fans and other installations.
2 Impact of vibrations on the human body
The human body is considered as a combination of masses with elastic elements that have natural frequencies, which for the shoulder girdle, hips and head relative to the supporting surface (standing position) are 4-6 Hz, for the head relative to the shoulders (sitting position) - 25-30 Hz For most internal organs, natural frequencies lie in the range of 6-9 Hz. General vibration with a frequency of less than 0.7 Hz, defined as pitching, although unpleasant, does not lead to vibration disease. The consequence of such vibration is seasickness, caused by disruption of the normal activity of the vestibular apparatus due to resonance phenomena.
When the oscillation frequency of workplaces is close to the natural frequencies of internal organs, mechanical damage or even ruptures are possible. Systematic exposure to general vibrations, characterized by a high level of vibration velocity, leads to vibration disease, which is characterized by disturbances in the physiological functions of the body associated with damage to the central nervous system. These disorders cause headaches, dizziness, sleep disturbances, decreased performance, deterioration of well-being, and cardiac dysfunction.
The amplitude and frequency of vibration significantly influence the severity of the disease and, at certain values, cause vibration disease (Table 1).
Table 1 - Effect of vibration on the human body
|
Vibration oscillation amplitude, mm |
Vibration frequency, Hz |
Impact result |
|
Various |
Does not affect the body |
|
|
Nervous agitation with depression |
||
|
Changes in the central nervous system, heart and hearing organs |
||
|
Possible illness |
||
|
Causes vibration disease |
The characteristics of the impact of vibration are determined by the frequency spectrum and the location within its limits of the maximum levels of vibration energy. Local vibration of low intensity can have a beneficial effect on the human body, restore trophic changes, improve the functional state of the central nervous system, accelerate wound healing, etc.
With an increase in the intensity of vibrations and the duration of their influence, changes occur, leading in some cases to the development of occupational pathology - vibration disease.
Among occupational diseases, vibration disease occupies one of the leading places. The etiological factor in the development of the disease is industrial vibration. Concomitant factors such as static-dynamic loads, cooling and wetting of hands, noise, forced working posture, reduce the time of development of the disease and determine some features of the clinical picture of the disease. The highest incidence of vibration disease is recorded in enterprises of heavy, energy and transport engineering, mining industry and amounts to 9.8 cases per 100 thousand workers...transport engineering, mining industry and is 9.8 cases per 100 thousand workers.
Among occupational diseases, vibration disease occupies one of the leading places. The etiological factor in the development of the disease is industrial vibration. Concomitant factors such as static-dynamic loads, cooling and wetting of hands, noise, forced working posture, reduce the time of development of the disease and determine some features of the clinical picture of the disease. The highest incidence of vibration disease is recorded in enterprises of heavy, energy and transport engineering, and the mining industry and amounts to 9.8 cases per 100 thousand workers.
When studying the biological effect of vibration, the nature of its distribution throughout the human body is taken into account, which is considered as a combination of masses with elastic elements. In one case, this is the entire torso with the lower part of the spine and pelvis (standing person), in the other case, the upper part of the torso in combination with the upper part of the spine, bending forward (seated person).
BIOLOGICAL IMPACT OF VIBRATION ON THE BODY
For a person standing on a vibrating surface, there are two resonance peaks at frequencies of 5 - 12 Hz and 17 - 25 Hz, for a person sitting - at frequencies of 4 - 6 Hz. For the head, resonant frequencies lie in the region of 20 - 30 Hz. In this frequency range, the amplitude of head vibrations can exceed the amplitude of shoulder vibrations by three times. For a lying person, the region of resonant frequencies is in the range of 3 - 3.5 Hz. One of the most important oscillatory systems is the combination of the chest and abdominal cavity. Oscillations in this system occur in a standing position. Vibrations of the internal organs of these cavities exhibit resonance at frequencies of 3 - 3.5 Hz. The maximum amplitude of vibrations of the abdominal wall is observed at frequencies from 7 to 8 Hz, and the anterior wall of the chest - from 7 to 11 Hz.
As the vibration frequency increases, its transmission throughout the human body weakens. In a standing and sitting position, the amount of attenuation in the pelvic bones increases by 9 dB per octave of frequency change, on the chest and on the head - 12 dB, on the shoulder - 12 - 14 dB. These data do not apply to resonant frequencies, under the influence of which the oscillatory speed increases rather than weakens. Under conditions of transmission through the hand with a pressing force of 10 kg, vibration attenuation at the back of the hand occurs with a slope of 2.5 dB per octave, and at the head with a slope of 16 dB per octave.
The human hand can be represented by an equivalent system consisting of concentrated masses of elasticity and resistance. The coefficients characterizing the elasticity of the mass and the oscillatory losses of the arm depend mainly on the degree of tension in the arm muscles and the posture of the worker. On the handle of a hand-held machine, when working with it, there is one maximum - in the region below 5 Hz and a second intense maximum - in the frequency region 30 - 40 Hz, which corresponds to the resonance of the “effective mass of the hand” system (approximately 1 kg) and the elasticity of soft tissues of the inner side of the hand.
The mechanical system of the human straight arm has resonance in the frequency range 30 - 60 Hz. When vibrations are transmitted from the palm to the back of the hand, the amplitude of vibrations at a constant frequency of 40 - 50 Hz decreases by 35 - 65%. In areas between the hand and elbow, elbow and shoulder, further weakening of vibrations occurs. The greatest attenuation is observed in the shoulder joint and on the head. With increasing pressure on the handle, there is a proportional increase in vibration conductivity on the shoulder, amounting to 1.2 dB per doubling of pressure for a frequency of 8 Hz, about 3 dB for a frequency of 16 Hz and 4 - 5 dB for frequencies of 32 - 125 Hz. As the force applied to the instrument increases, not only will a person receive a large amount of vibrational energy due to an increase in the input mechanical impedance, but the impact of vibration will spread over a larger receptive area.
The characteristics of the impact of industrial vibration are determined by the frequency spectrum and the distribution within its limits of the maximum levels of vibration energy.
Local vibration of low intensity can have a beneficial effect on the human body, restoring trophic changes, improving the functional state of the central nervous system, accelerating wound healing, etc. With an increase in the intensity of vibrations and the duration of their impact, changes occur, leading in some cases to the development of occupational pathology - vibration disease. Pathology has the greatest share (distribution), in the etiopathogenesis of which local vibration plays a significant role.
According to the concept developed in our country, recognized in a number of countries in Eastern Europe and Japan, vibration disease is considered an occupational disease of the whole organism.
In Western Europe and the USA, the syndrome associated with whitening of the fingers is mainly considered as an occupational disease caused by exposure to local vibration. These vascular disorders have different names, for example, the phenomenon of “dead”, white fingers or Raynaud's syndrome of occupational origin, traumatic vasospastic disease; a later name is vibration-induced white fingers (VWF). However, the clinical symptoms of vibration disorders are not limited to vascular lesions; they also include neurotic disorders, which is gradually beginning to be recognized abroad.
In many countries, the classification of vibration syndrome developed by W. Taylor And P. Pelmear(1974). According to this classification, the severity of vibration disorders - whitening of the fingers (stage IV) is assessed depending on the number of phalanges involved in the pathological process, the frequency of whitening attacks, taking into account how much they interfere with work and rest.
In 1983 Rigby And Cornish proposed a more complete system for assessing disturbances from local vibration. The authors identified 4 categories: category I included a feeling of numbness and (or) tingling (not amenable to objectification), category II included episodic whitening of the fingers, the degree of which is assessed using a special digital scale, category III included acrocyanosis, constant circulatory insufficiency with deterioration of sensitivity, category IV - tissue necrosis of any phalanges of the fingers. In addition to the stage and quantitative assessment of the degree of whitening of the fingers, one of five categories of disability is indicated.
At the IV International Symposium on Local Vibration (1986), a modification of the classification was presented W. Taylor - P. Pelmear, where, in parallel with the vascular stages, neurological stages are also identified, the basis for the establishment of which is a decrease in tactile sensitivity and tactile spatial resolution. Muscular and osteoarticular disorders are not taken into account in foreign classifications.
In our country, a different approach to assessing vibration disorders is used. Developed for the first time in the world by E.Ts. Andreeva-Galanina et al. (1956) classification of vibration disorders - vibration disease as an independent nosological form, which makes it possible to identify a complex of the most common syndromes, has now been significantly developed.
The “Classification of vibration disease from exposure to local vibration”, approved in 1985 by the USSR Ministry of Health, establishes 3 degrees of severity of the disease:
-
initial manifestations (I degree);
-
moderate manifestations (II degree);
-
pronounced (III degree) manifestations.
Each degree is characterized by certain syndromes (peripheral angiodystonic, vegetative-sensory polyneuropathy, etc.), and in grade I only disturbances in the hands (vascular and sensory) are noted; in grades II and III the disturbances are more generalized.
In addition to peripheral vascular and sensory disorders, dystrophic disorders of the musculoskeletal system of the arms and shoulder girdle, cerebrovascular accidents and encephalopolyneuropathy syndrome are considered. The classification makes it possible to assess work ability depending on the nature of the observed syndromes.
In 1982, domestic scientists developed a classification of vibration disease from the effects of general vibration, which is based on the syndromic principle, taking into account the low-frequency nature of vibration, which spreads well throughout the human body and involves the vestibular analyzer in the process.
The classification distinguishes initial (I degree), moderately expressed (II degree) and pronounced (III degree) manifestations of vibration disease from general vibrations. In the clinical picture of vibration disease, the leading ones are cerebral-peripheral angiodystonic syndrome and autonomic-sensory polyneuropathy syndrome in combination with polyradiculoneuropathy syndrome, secondary lumbosacral syndrome (due to osteochondrosis of the lumbar spine).
Vibration disease, caused by exposure to general vibration and shocks, observed among operators of transport and transport-technological equipment, is characterized by vestibulopathy syndrome, which is manifested mainly by vestibulo-vegetative disorders - dizziness, headache, nausea, vomiting, adynamia, bradycardia, etc. Very characteristic also degenerative-dystrophic changes in the musculoskeletal system.
A special place in the clinic of vibration disease is occupied by pathology of the musculoskeletal system. The impact of general vibration leads to a direct microtraumatic effect on the spine due to significant axial loads on the intervertebral discs, which behave like low-frequency filters, being linear even in the case of local overloads in the spinal motion segment as a result of overstrain of postural tension muscles. The impact of external and internal loads on the spine leads to disc degeneration.
The localization of degenerative changes in the same part of the spine and the significant frequency of lumbar osteochondrosis in people in vibration-hazardous professions allows us to suggest a direct connection between these changes and the pathology of vibration genesis. It was noted that clearly defined osteophytes, as a rule, are localized on the lower edges of the I and II thoracic and lumbar vertebrae, as well as on the upper edges of the II, III and IV lumbar vertebrae.
It should be recognized that degenerative changes in the spinal column, along with changes of the same order in other parts of the skeleton in workers, are often found without connection with neurological symptoms. At the same time, pathological changes in the bone structure diagnosed on radiographs are sometimes the only and relatively early signs of vibration disease.
Another important point is the accelerating effect of vibration on the rate of natural involutive processes, therefore, the detection of degenerative changes, the severity of which is greater than should be expected for the age of the subjects, may indicate the presence of osteopathy caused by the vibration factor.
The pathogenesis of vibration disease is based on a complex mechanism of neuro-reflex and neurohumoral disorders, which lead to the development of stagnant excitation followed by persistent changes in both the receptor apparatus and various parts of the nervous system. The unfavorable effect of vibration on the human body is characterized by a local effect on tissues and numerous extero- and interoreceptors embedded in them (direct microtraumatic effect) and indirectly through the central nervous system on various systems and organs. An important role is played by secondary disorders as a result of trophic disturbances caused by vascular dysfunction. 
Clinical symptoms of vibration disease, caused by local or general vibration, consist of neurovascular disorders, lesions of the neuromuscular system, musculoskeletal system, metabolic changes, etc.
Both specific and nonspecific reactions of a general type, reflecting the adaptive-compensatory reactions of the body, are essential for the pathogenesis of vibration disease. Long-term study of this pathology has made it possible to establish various variants of its course with the predominant manifestation of neurovascular disorders or pathology of the musculoskeletal system.
The severity of clinical symptoms is determined primarily by the spectral and amplitude parameters of vibration and the conditions under which this effect occurs. Thus, exposure to low-frequency vibration leads to the development of vibration pathology with a predominance of lesions of the neuromuscular system, musculoskeletal system and a less pronounced vascular component. For example, this form is observed among molders, drillers, etc. Medium- and high-frequency vibration causes vascular, neuromuscular, osteoarticular and other disorders of varying degrees of severity. When working with grinding machines and other sources of high-frequency vibration, mainly vascular disorders occur.
As a result of the influence of intense local vibration, functional changes first occur, and then dystrophic changes in the receptor apparatus and perivascular nerve plexuses of small vessels in the area of the upper extremities. Gradually, other parts of the peripheral and central nervous system are involved in the process.
The damaging effect of vibration causes a decrease in the function of homeostatic regulation of tissue metabolism. Local damage to the vascular intima also occurs. The activity of blood alkaline phosphatase increases, the ratio of the content of nucleic acids - RNA and DNA - changes, and the activity of succinate dehydrogenase decreases.
An important role in initiating an attack of whitening of the fingers is played by exposure to cold, causing a reflex vasoconstriction mediated by the sympathetic system. This hypothesis is supported by the results of a histological study of the tissues of the fingers, which showed that, along with other disorders, in these cases there is a pronounced hypertrophy of the muscles of the vascular wall. 
Oxygen imbalance aggravates microcirculation and vascular permeability disorders. The study of various links in the pathogenesis of vibration disease (neurohumoral, microcirculatory, hormonal, enzymatic) suggests that changes in tissue metabolism and the development of dystrophic processes are associated with the presence of disturbances in both local enzyme systems and central reflex influences on tissue metabolism.
Oxygen deficiency also contributes to the development of trophic disorders in the distal parts of the upper extremities, in particular the occurrence of myofibrosis, arthrosis and periatrosis, the formation of cysts, enostosis, and a decrease in the mineral component of bone tissue. Capillary and precapillary blood circulation in the fingers suffers, and subsequently the tone of large vessels (arteries and veins) on the forearms and shoulder changes, which clinically manifests itself in the form of angiodystonic (or angiospastic) syndrome.
Changes in the blood coagulation system, which contribute to disruption of microcirculation and progression of the process, have a certain significance in the pathogenesis of vibration disease. Along with the above, changes in the mechanisms of autonomic-vascular regulation associated with the altered functioning of higher autonomic centers and the reticular formation of the brain stem, as well as peripheral autonomic ganglia, have a great influence on the development of peripheral hemodynamic disorders.
Vascular disorders in vibration disease tend to generalize, which in severe cases can lead to the gradual development of chronic cerebral circulatory failure.
There are also changes in the function of the hypothalamic-pituitary-adrenal system; the ratio of vasoactive substances of the renin-angiotensinaldosterone system is disrupted, shifts appear in the ratio of hormones of the pituitary-thyroid complex, changes in the content of cyclic nucleotides and an increase in the level of prostaglandins in the blood, shifts in calcium-magnesium metabolism, etc. In some cases of vibration disease, changes in immunological parameters are observed; in severe forms of vibration pathology, a disturbance in the functional activity of T- and B-lymphocytes was noted.
It has been established that the development of peripheral polyneuropathy is accompanied by changes in cholinesterase activity in muscles. Disorders of motor function that arise under the influence of local vibration are caused by both a violation of the coordinating influences of the cortical part of the analyzer on the periphery, and direct damage to the muscles.
When working with heavy pneumatic tools, when there is significant tension in the upper extremities, myofasciculitis, myositis of the muscles of the shoulder girdle, and tendomyositis of the forearm are often observed.
Destructive-dystrophic processes in the osteoarticular apparatus are often detected.
Thus, in the genesis of vibration disease from exposure to local vibration, both local damage to tissue structures that provide homeostatic regulation of tissue metabolism and disruption of the central (humoral and neuroreflex) mechanisms of regulation of peripheral blood circulation, which contributes to the aggravation of the pathological process, play a role.
As for the pathogenesis of vibration disease from exposure to general vibrations, it remains insufficiently studied to date. A generalized clinical and physiological picture of the effect of general vibration allows us to formulate a hypothesis about the mechanism of the direct microtraumatic effect of vibration on the musculoskeletal system, vestibular-mediated and extravestibular reactions. The frequency and severity of violations depend on the physical characteristics of vibration, ergonomic parameters of the workplace, and medical and biological parameters of the human operator.
As is known, vibration disease differs from general vibration in its polymorphism, and the observed early peripheral and cerebral autonomic-vascular disorders are often of a nonspecific functional nature.
According to modern concepts, the pathogenetic mechanism of the formation of vibration disorders from the influence of general vibration is a complex process consisting of three main interrelated stages.
The first stage is receptor changes, characterized by dysfunction of the vestibular apparatus, and associated functional disorders of vestibulosomatic, vestibulo-vegetative, vestibulosensory reactions.
The second stage is degenerative-dystrophic disorders of the spine (osteochondrosis), which arise in the presence of exogenous and endogenous factors, and the associated phenomena of decompensation of the trophic system.
The third stage is the loss of adaptive abilities of the balance organs and associated disturbances in the functional state of the optovestibulospinal complex due to pathological vestibuloafferentation.
Based on clinical, functional and experimental studies, it has been established that one of the pathogenetic mechanisms of vibration disease, along with neuro-reflex disorders, is an increase in venous resistance, a change in venous outflow leading to venous congestion, an increase in fluid filtration and a decrease in tissue nutrition with the subsequent development of peripheral angio-dystonic syndrome. Low-frequency vibration leads to changes in the morphological composition of the blood: erythrocytopenia, leukocytosis; there is a decrease in hemoglobin levels.
The influence of general vibration on metabolic processes, manifested in changes in carbohydrate metabolism, was noted; biochemical blood parameters characterizing disorders of protein and enzymatic, as well as vitamin and cholesterol metabolism. Disturbances in redox processes are observed, manifested in a decrease in the activity of cytochrome oxidase, creatine kinase, an increase in the concentration of lactic acid in the blood, changes in nitrogen metabolism, a decrease in the albumin-globulin coefficient, and changes in the activity of coagulating and anticoagulant factors in the blood.
A change in mineralcorticoid function has been established: a decrease in the concentration of sodium ions in the blood, an increase in the excretion of sodium salts and a decrease in potassium salts. There is a disruption of the endocrine system: the neurohumoral and hormonal regulation of functions is disrupted, manifested in changes in histamine-serotonin levels, hydrocortisone content, 17- oxycorticosteroids, catecholamines. 
General vibration also has a negative effect on the female genital area, which is expressed in menstrual disorders, algodismenorrhea and menorrhagia; impotence is often observed in men; These violations are most typical for operators of transport and transport-technological equipment exposed to jolt-like vibration.
With all types of vibration disease, changes in the central nervous system are often observed in the form of vegetative dysfunction on a non-vasthenic background, which may be associated with the combined effect of vibration and intense noise that constantly accompanies vibration processes.
For the same reason, workers in vibration-hazardous professions with extensive experience experience neuritis of the auditory nerves; in advanced stages of the disease, there is a decrease in hearing not only for high, but also for low tones.
Thus, numerous studies by domestic and foreign specialists have shown that vibration disease differs from local and general vibrations in the polymorphism of symptoms, the uniqueness of the clinical course, and can often lead to impairment of the patients’ ability to work.
STATISTICS OF THE OCCUPATION OF VIBRATION OCCUPATIONAL PATHOLOGY
According to statistics, a third of identified occupational diseases are associated with exposure to vibration and noise. According to the structure in the total share of occupational diseases: 1991 - 22.5%; 1992 - 22.7%; 1993 - 24.1%; 1994 - 26.9%; 1995 - > 25. Moreover, during medical examinations, only 1 - 10% of real cases of disease are detected. The highest incidence of vibration disease is recorded in enterprises of heavy, energy, transport engineering, coal industry and non-ferrous metallurgy.
Incidence rate of vibration disease in the main vibration hazardous areas
professions and average values of the latent period
|
Professional group |
Morbidity rate in vibration-hazardous professions, per 1000 people |
Latent period, years |
|
Casting cutter |
5,4 | 10.8 ± 0.3 |
|
sandpaper |
2,6 | 12.1 ± 0.7 |
|
Forest feller |
4,0 | 14.4 ± 0.4 |
|
Grinder |
0,5 | 14.5 ± 0.6 |
|
Sharpener |
3,9 | 14.7 ± 1.0 |
|
Mechanical assembly mechanic |
0,3 | 16.8 ± 0.6 |
|
Rodman |
0,5 | 17.4 ± 1.2 |
|
Longwall miner |
2,2 | 17.8 ± 0.5 |
|
Driller |
5,9 | 17.9 ± 0.8 |
|
Pathfinder (telescopes) |
23,4 | 17.9 ± 0.9 |
|
Driller (electric drills) |
1,3 | 18.1 ± 1.4 |
|
Riveter |
0,2 | 20.1 ± 1.2 |
|
Moulder |
1,0 | 18,2 + 0,8 |
The human body is like an oscillatory system. Vibrations are the vibrations of a solid body around an equilibrium (rest) position. In this case, either the entire body vibrates in space as a single 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 oscillations can exist both separately and together.
Vibrations as a physical phenomenon are based on the oscillatory process and the wave motion of its propagation in the medium. When vibrations propagate, the amount of vibrational energy transferred by a 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 provided by the body to the vibrations. Propagating from the excitation zone throughout the human body, vibrations cause alternating stresses in the body tissues (compression, stretching, shear, torsion or bending). Changes in stress are captured by many receptors located in tissues not only in the area of contact with a vibrating surface, but also in the area of propagation of vibrations, and the vibrational energy transferred to a person is partially spent on friction in tissues and joints, turning into thermal energy, and is partially transformed by receptors into energy biochemical and bioelectric processes that occur 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 unfavorable factors accompanying vibration - uncomfortable working posture, static stress, uncomfortable microclimate, intense noise, etc.
Systematic prolonged exposure to vibration, significantly exceeding the thresholds for its perception, can cause persistent disturbances in normal physiological functions in the body.
Vibrations are perceived by different organs and parts of the body. Thus, with low-frequency (up to 15 Hz) vibrations, translational vibrations are perceived by the otolith, and rotational vibrations by the vestibular apparatus of the inner ear. When in contact with the vibration of a solid body, the perception of vibration is carried out by the nerve endings of the skin.
A person feels vibrations from fractions of a hertz to approximately 80 Hz, and high-frequency vibrations 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. Sources of vibration can also be industrial installations, vehicles (metro, railway), which create large dynamic loads during operation, which cause the spread of vibration in the ground and building structures. These vibrations are also often the cause of noise in buildings.
Unlike the industrial environment, vibration in residential areas can operate around the clock, causing irritation and disrupting a person’s rest and sleep.
The influence of vibrations on the human body. Vibration disease. Vibrations from power tools, technological equipment or means of transport always affect a person under certain specific conditions: working posture and static body tension; microclimate and dust and gas composition of the air environment; accompanying 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 degree of severity of disturbances in physiological functions that can be observed as a result of prolonged repeated action and the individual characteristics of the body and, in particular, the state of nervous processes - their strength, balance and mobility.
According to the method of influence, vibrations are conventionally divided into general - acting through the supporting surfaces of the body in a standing, sitting or lying position, and local - acting through the palmar surfaces of the hands.
When vibration affects a person, changes are observed in many organs and systems, varying the severity of individual symptoms. In some cases, vascular disorders are more pronounced, in others - dysfunction of the musculoskeletal system.
Significant changes are found in the autonomic nervous system. When the vibration of a power tool affects the human body, the following disturbances in physiological functions occur. First of all, vibration sensitivity is impaired. The vast majority of people in vibration-hazardous professions have elevated vibration sensitivity thresholds. Vibration with a low frequency of up to 30 Hz mainly causes disturbances in pain sensitivity. Its changes begin from the fingertips, cover the entire hand and lower part of the forearm, like a short or long glove.
With the simultaneous effect of vibration and noise, cases of a pronounced form of occupational hearing loss can be observed among people with extensive experience.
With local vibration, the regulation of the tone of peripheral blood vessels primarily suffers, and the plasticity of the lymphatic bed is disrupted. Direct mechanical and reflex irritations of vascular smooth muscle cells lead to spasms.
With local vibration, pathological changes occur in the neuromuscular system: electrical excitability and lability of muscles and peripheral nerves decrease, bioelectrical activity in the resting muscle increases, and motor coordination is impaired. Strength, tone and endurance of muscles decrease, pockets of compaction and painful cords appear in muscle tissue, and atrophy develops.
General vibration causes similar disorders in the entire motor sphere of the body, caused by both mechanical injuries 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. Inhibitory processes predominate in the cerebral cortex, normal cortical-subcortical relationships are disrupted, and autonomic dysfunctions occur. As a result, the general physical and mental condition of the body deteriorates, which can be expressed in fatigue, depression or irritability, headaches and other nervous disorders, including persistent neuroses.
Vibration can affect all sensory systems. With local vibration, a decrease in temperature, pain, vibration, and tactile sensitivity occurs. With general vibration, visual acuity decreases, the field of vision decreases, the light sensitivity of the eye decreases, and the blind spot increases; the perception of sounds worsens, the activity of the vestibular apparatus is disrupted. Hemorrhages are detected in the tympanic cavity of the middle ear and semicircular canals. Vibrations can cause a concussion.
Due to the stressful nature of vibration, the entire system of neurohumoral regulation is disrupted, as well as metabolic processes, the function of the digestive system, liver, kidneys, and genitals. As a mechanical factor, vibration causes a violation of the hydrodynamic balance in tissues and internal organs, an increase in the total energy expenditure of the body with corresponding shifts in oxidative processes, disturbances in the respiratory and vocal apparatus, and injuries 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 the parts and the amount of vibrational energy transmitted to the entire human body or a limited area of it, as well as factors accompanying the development of vibration disease: return blow from a hand tool, forced position of the body, cooling, noise.
The basis of vibration disease is a complex mechanism of nervous and reflex disorders, which lead to the development of foci of stagnant excitation and persistent subsequent changes both in the receptor apparatus and in various parts of the central nervous system. Specific and nonspecific reactions, reflecting the body's adaptive and compensatory processes, also play a significant role in the pathogenesis of vibration disease. It is believed that vibration disease is a process in which spasm of small and larger vessels is observed. Trophic changes in the skin and nails are possible, up to the development of gangrene of the fingers and toes. Atrophy of the muscles of the arms and shoulder girdle occurs. In the spinal cord - degenerative changes in nerve cells, minor hemorrhages, necrosis. In the osteoarticular apparatus of the upper limb there is aseptic necrosis of the articular parts of the bones, which is a reflection of atrophic, dystrophic, necrotic and regenerative processes in cartilage, articular capsules, and bones. In the bone tissue there are pockets 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 observed.
Vibration disease, caused by exposure to local vibration, has complex clinical symptoms. The disease develops gradually. The patient complains of pain in the hands, sometimes cramps in the fingers, increased sensitivity to cold, irritability, and insomnia. The leading place is occupied by vascular syndrome, accompanied by attacks of whitening of the fingers after general or local cooling of the body, as well as disturbances of sensitivity - vibration, pain, temperature. Vascular disorders manifest themselves 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 exposure to general vibration, is marked by significant changes in the central nervous system. Functional disorders of the digestive glands, gastritis, and metabolic disorders are noted.
There are four stages of vibration disease: Stage I - initial, low-symptomatic, complaints of mild pain in the hands with mild sensitivity disorders at the fingertips predominate; Stage II - moderately expressed, 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 disturbances, sensitivity disorders, noticeable changes in the functional state of the central nervous system, changes are persistent and slowly respond to treatment; Stage IU - symptoms are pronounced, vascular disorders in the arms and legs, disorders of the coronary and cerebral vessels, the condition is persistent and 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 activities:
· reduction of vibration at the source of their formation by design and technological measures (changes in the operating cycle scheme, use of materials with high internal friction;
· reduction of vibration along the propagation path can be achieved by means of vibration isolation and vibration absorption: the use of spring and rubber shock absorbers, gaskets, lining handles and other contact points with vibration-absorbing materials, and the installation of vibration-isolating bushings;
· combating associated adverse factors in the production sector. So, to protect the hearing organ from noise when working with vibrating equipment, it is recommended to have individual noise suppressors; these include earmuffs, headphones and helmets.
II. Work and rest schedule.
III. Therapeutic and preventive measures.
Vibration therapy as a method of physiotherapy. Vibration therapy is a method of physiotherapy that involves applying mechanical vibrations of low frequency and amplitude to various parts of the body or the entire body of the patient. It has long been known that vibration has healing properties. It was used in explicit and implicit forms: riding a cart, horseback riding, acoustic effects, rhythmic dances. These observations and centuries of experience have led to the need to develop special devices and methods that allow the targeted use of vibration for therapeutic effects either on the whole person, or on individual parts of his body, or locally 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 areas 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 rhythmically tapping the patient’s body with the palms of a massage therapist or using mechanical vibration devices of various designs.
Mechanical vibrations during vibration therapy can be transmitted from their source and through the water of the bath 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 the impact 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 body the mechanical irritation is directed to. In the area of influence, a decrease in pain or varying degrees of “numbness” is noted, depending on the intensity of the stimulus used and the nature of the disease.
In the mechanism of action of vibration therapy, the most important is the transmission of locally applied stimulus from baroreceptors through conducting fibers to the posterior columns of the spinal cord and from here to the thalamus and cerebral cortex. Irritation spreads within the corresponding metamere of the body, including its internal organs.
Vibration therapy can have an analgesic, anti-inflammatory effect, stimulate metabolic processes in muscle tissue, and improve peripheral circulation.
Indications for recovery: consequences of injuries to 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, severe dysfunction of the endocrine system, thrombophlebitis, pregnancy, condition after a recent (up to 1 year) injury to the brain and spinal cord.
Lecture No. 20
Water and health
Water content in the human body. The adult human body contains about 65% water. Thus, in men, about 61% of body weight is water, and in women - 54%. The difference is due to the large amount of fat in a woman's body. It should also be noted that the younger the organism, the greater the proportion of water in its composition. Thus, a 6-week embryo contains 97.5% water, a newborn body contains 70-83%, and in old age it decreases to 50%. Water in the body can be free, forming the basis of intracellular fluid; constitutional, an integral part of the molecules of proteins, fats and carbohydrates; bound, part of colloidal systems. Water is involved in the regulation of body temperature and hematopoiesis.
Most of the water is inside cells - 71%, outside cells - 19%, in 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. Blood plasma contains 92% water, and digestive juices contain 98-99% or more.
Water in the body performs the following functions:
· the process of digestion occurs in the aquatic environment;
· in aqueous solutions and with the participation of water, metabolism and hematopoiesis take place;
· without water, absorption processes and all chemical and enzymatic processes are impossible;
· with the help of water, food products are transported in the body, as well as their absorption;
· water participates in thermoregulation processes;
· toxic wastes are removed from the body with water;
· Water is a universal solvent.
The constancy of the volumes of fluids in the internal environment of the body is ensured by water-salt metabolism. Water entering the body from the stomach and intestines penetrates the blood and spreads throughout the body. In the body, water is distributed between various liquid phases in accordance with the concentration of osmotically active substances in them.
Daily balance of water in the body. Drinking regime. In the process of evolution, the human body has developed a complex mechanism that ensures normal water balance - the amount of water consumed must be equal to its consumption. A person’s water balance is calculated by daily water consumption, as well as its excretion from the body. A person receives an average of 2.5 liters of water per day: 1.2 liters - from the liquid he drinks, 1 liter - along with food products that contain water, 0.3 liters of water are formed in the body itself in the process of metabolism - this is the so-called endogenous water. The same amount of liquid must be removed from the body within 24 hours.
An adult needs 2.5-3 liters of water per day - in food and drinking water, because... This approximately 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, the nature of the diet, and especially the salt content of the food. For example, when working in a hot climate, the total daily need for water in food and drinking increases to 10 liters.
Water is also formed in the body itself during the oxidation of nutrients. It is found in large quantities in some foods, for example, 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 breakdown of organic substances, 12 cm 3 of water is formed, 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 contained in food. Per day, about 1.5 liters are excreted from the body of an adult in urine, 100-200 cm 3 in feces, 500 cm 3 through the skin, and 350-400 cm 3 through the lungs. This way the water balance is maintained.
When there is a lack of water in the body, a feeling of thirst appears, which is expressed by a peculiar feeling of dryness in the mouth and pharynx. The center that regulates water metabolism is localized in the brain stem. The main cause of thirst is a violation of the optimal relationships between water, salts and organic substances in the blood, resulting in an increase in the osmotic pressure of the body fluid.
Drinking regime- rational order of water consumption. A properly established drinking regime ensures a normal water-salt balance and creates favorable conditions for the life of the body. Disorderly, excessive drinking impairs digestion, creates additional stress on the cardiovascular system and kidneys, and leads to an increase in the release of a number of substances valuable to 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 cramps. Insufficient water consumption also disrupts the normal functioning of the body: body weight falls, blood viscosity increases, body temperature rises, pulse and breathing increase, thirst and nausea occur, and performance decreases.
The minimum amount of water required to maintain water-salt balance during the day (drinking norm) depends on climatic conditions, as well as the nature and severity of the work performed. For example, for temperate latitudes, the amount of water administered with drinking and food with minimal physical activity is 2.5 liters per day, with moderate physical activity up to 4 liters, in the climate of Central Asia with minimal physical activity 3.5 liters, with physical activity for moderate work up to 5 liters, for heavy work outdoors up to 6.5 liters.
It is especially important to maintain the correct drinking regime in conditions that cause large losses of fluid from the body, which often occurs in hot climates, when working in hot shops, during prolonged and significant physical activity (for example, during training and competitions, mountain climbing). Residents of areas with hot climates are advised to completely quench their thirst only after satiety and strictly limit fluid intake between meals. To quench thirst, use tea, which increases salivation and eliminates dry mouth, and adds fruit and vegetable juices or extracts to water. In hot shops they drink sparkling water or decoctions of dried fruits. The drinking regime of athletes involves quenching thirst after finishing exercise. When climbing mountains, it is recommended to quench your thirst only during long breaks. For significant weight loss associated with heavy physical activity (after training, sports competitions, steam bath), it is recommended to drink in fractional portions.
Consequences of lack and excess of water in the human body. Both a lack and an excess of water in the body, under certain conditions, can be the main cause of disruption of certain functions, including the development of chronic diseases. A 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 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, limitation or cessation of water intake.
The body can lose a significant amount of water through the intestines (with diarrhea, the action of laxatives), the stomach (with profuse vomiting), the kidneys (diabetes mellitus, the action of diuretics), the skin (increased sweating), the lungs (with an increase in ventilation in dry air conditions) , as a result of blood loss, with extensive burns and wounds. When performing work, the greatest loss of water through sweat is observed when the body is overheated. When climbing high mountains, increased loss of water is facilitated by increased sweat production 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 the volume of ventilation and dry air. Dehydration may be caused by water loss associated with a long-term carbohydrate-free diet. With a loss of water in an amount of less than 2% of body weight, thirst appears, with a loss of 6-8% - a semi-fainting state, 10% - hallucinations and difficulty swallowing, and with a deficit of more than 12%, death occurs.
Clinically, dehydration is manifested by a decrease in body weight, severe thirst, loss of appetite, and nausea. The mucous membrane becomes flabby, wrinkled, loses elasticity, and the fold of the abdominal skin does not smooth out for a long time. Blood and intraocular pressure decrease, pulse increases and weakens. Weakness increases, headaches, dizziness, unsteady gait occur, and coordination of movements is impaired. Muscle strength and attention weaken, and performance decreases. Sometimes body temperature rises. As the clinical picture worsens, a further decrease in body weight occurs; the eyeballs sink, facial features become sharpened, vision and hearing weaken, swallowing is severely difficult; circulatory failure increases, urination becomes painful, and the psyche is disturbed. With severe dehydration, the feeling of thirst may be lost. If a person is in relative peace and in a moderate ambient temperature, he can live without water for a week (without food for about a month), and in conditions of elevated temperature - only three days.
Excess water is a common form of disruption of 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 the blood and plasma increases, as a result of which the hematocrit indicator decreases. Hydration of cells is observed. Body weight increases. Nausea and vomiting are typical. The mucous membranes are moist. Dehydration of brain cells is indicated by apathy, drowsiness, headache, muscle twitching, convulsions, poor coordination of movements, and muscle weakness. Excess water leads to overload of the cardiovascular system, causing debilitating sweating, accompanied by loss of salts and water-soluble vitamins, weakening the body. With excess water, profuse salivation, a drop in temperature, and increased urine production are observed.
Indications and methods of using mineral waters. Mineral springs of the Republic of Belarus. Mineral waters are underground (sometimes surface) waters with a high content (more than 1 g/l) of mineral salts and gases, which have physical and chemical properties (chemical composition, temperature, radioactivity) that allow them to be used for medicinal purposes. Some mineral waters are of industrial importance. According to mineralization they are distinguished: low mineralization (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 strong brine (above 150 g/l) mineral waters. According to their ionic composition, mineral waters are divided into chloride (Cl -), hydrocarbonate (HCO 3 -), sulfate (SO 4 2-), sodium (Na +), calcium (Ca 2+), magnesium (Mg 2+). Based on the presence of gases and specific elements, they distinguish: carbon dioxide, sulfide (hydrogen sulfide), nitrogen, bromide, iodide, ferruginous, arsenic, silicon, radioactive (radon) mineral waters. Based on temperature, they are distinguished: 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 ancient medieval doctors in Europe and the Arab East. The first mention of their medicinal properties is in the works of the Greek physician Hippocrates (18th century BC), where some information is provided about the properties of salt and sea water. In the CUI century, the experience of treatment with mineral waters that had accumulated by that time was summarized by the Italian physician G. Phillopia in the book “Seven Books on Dark Waters.” In the CUI-CUII centuries, issues of construction, equipment and operation of resort areas with various mineral waters began to be more widely considered. In Russia, state activities for the exploration of mineral waters and their exploitation for medicinal purposes were launched on the initiative of Peter I.
Medicinal mineral waters are usually understood as underground waters that contain high concentrations of various mineral (less often organic) components and gases or have any special physical properties (radioactivity, elevated temperature), due to which mineral waters have a healing effect on the human body when applied 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 their medicinal properties, mineral waters are divided into 8 balneological groups: without “specific” components and properties, carbon dioxide, sulfide (hydrogen sulfide), arsenic, ferruginous, iodine-bromine with a high content of organic substances, siliceous thermal and radon.
Depending on the mineralization, mineral waters are used for both internal and external 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. When using mineral water internally, the physiological effect and therapeutic effect depend on the amount of water taken, its temperature, mineralization, chemical composition, time of intake in relation to food intake, and the functional state of the digestive system. This combines the different effects of using mineral waters. Thus, chloride and sulfate waters of high mineralization (more than 15 g/l) can have an irritating effect on the gastric mucosa and cause exacerbation of diseases. The laxative effect of sodium and magnesium sulfate waters begins when their sulfate ion content is more than 2.5 g/l.
Mineral water with the same total mineralization, different chemical compositions, has different effects on the human body. For example, sodium chloride waters have a beneficial effect on the digestive organs; calcium chlorides promote anti-inflammatory processes and have a positive effect on the nervous system; magnesium chloride promotes dilation of blood vessels; sulfate waters are mainly choleretic and laxative. Sodium bicarbonate (such as Borjomi) reduce acidity.
The therapeutic effect of sodium chloride waters when used externally (baths) is determined by thermal, chemical and gas components that improve the activity of the cardiovascular and nervous systems, 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 functioning of the heart, and helps 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 hematopoietic processes. They are used in the treatment of iron deficiency anemia. Arsenic mineral waters are more often used for oral administration. They are prescribed for exhaustion and anemia. Siliceous thermal waters are used to treat chronic gastritis, colitis, liver diseases, metabolism, and sulfide mineral waters are used to 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, movement organs, 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 so far used. Mineral waters of the republic with a salinity from 1.7 to 4.40 g/l are predominantly cold (10-15 0 C), with the exception of deep brines with temperatures up to 89 0 C, non-carbonated nitrogen (gas saturation up to 35 g/l), in most cases without specific components. According to the chemical composition, there are calcium-magnesium sulfate, sodium chloride, sodium-calcium chloride-sulfate, sodium chloride-sulfate, sodium chloride and calcium chloride 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 (Vasilievka sanatorium), in the Brest region (Berestye sanatorium).