PHYSIOLOGY OF WORK

From Big Medical Encyclopedia

PHYSIOLOGY of WORK (Greek

phy-sis the nature of 4 logos the doctrine) — the section of physiology studying changes of a functional condition of a human body under the influence of its work and proving from positions of physiology methods and funds of the organization of labor process allocated for maintenance of high performance and preservation of health of workers.

Main objectives F. t. are: studying fiziol. patterns of work of the person; research fiziol. parameters of an organism at different types of works; development of the practical actions directed to optimization of labor process, decrease in fatigue working and preservation of their health.

Physiological mechanisms of labor processes. In work the person should carry out different types of work. In a basis of both physical, and intellectual labor action of working the purpose, on a basis a cut in c lies. the N of page is created the certain action program which is implemented according to P. K. Anokhin, in the system and organized behavioural act (see. Functional systems).

In the course of labor action in c. the N of page arrives information

on the course of implementation of the program, on the basis a cut the current amendments to action are possible (touch corrections, according to N. A. Bernstein; allowances for to a basis of the return afferen-tation, according to P. K. Anokhin). Accuracy of programming and success of implementation of the program depend on experience and the number of the previous repetitions of this action, automatism.

Even prior to work as a result of the created program the level of activity of a row fiziol increases. the systems providing performance of this work. This phenomenon carries the name of a precautionary innervation or predna-building. During labor process various fiziol. systems become more active in a bigger degree.

At physical work first of all the muscular system and system of so-called vegetative ensuring muscle performance (blood circulation, breath) becomes more active. At hard physical activity the level of exchange processes and amount of the oxygen consumed in a minute, minute volume and a respiration rate, number of cordial reductions, etc. increases.

In the course of cerebration various departments of a cerebral cortex become more active, in to-rykh the blood stream and oxygen consumption increases; with increase in degree of intellectual or nervno-emotsional-ny tension activity of sympathoadrenal system is significantly stirred up, increase of pulse, increase in the ABP is observed, intensity of exchange processes increases.

Activation of functional systems of an organism causes increase in level of a metabolic cost of an organism. Already in operating time there is an intensification of recovery processes, generally processes of recovery are carried out after stoppage. Property of an organism quickly enough to compensate the energy spent in operating time is result of exercises in this type of work. Strengthening exchange processes, labor loading promotes improvement of a functional condition of a human body and preservation of his health. All this allows to consider process of activation fiziol. functions and the level of exchange processes at work as one of the essentialest moments biol. values of work.

V F. t. concepts of working capacity and exhaustion yalyatsya by the major. Understand potentiality of the person as working capacity to execute throughout the set time and with sufficient efficiency a certain number of work. In a production situation under the influence of various factors working capacity changes throughout change and is conditionally subdivided into several phases. The first phase — a phase of a vrabatyvayemost, in time a cut under the influence of conditioned excitators raises activity of c. the N of page, increases the level of exchange processes, activity of cardiovascular system amplifies that leads to increase in working capacity. This phenomenon is caused by gradual inclusion various psikhofiziol. functions, establishing various regulatory processes providing the level of functioning of an organism, optimum for this situation. The second phase — a phase of rather steady working capacity, characteristic feature a cut is optimum level of functioning of c. N of page. At this time efficiency of work is maximum. The third phase — the phase of decrease in working capacity connected with development of exhaustion. The fourth phase — - a phase of secondary increase in working capacity. The uslovnoreflektorny mechanism connected with the forthcoming end is its cornerstone? works and subsequent rest.

Working capacity depends on conditions of the environment, in a cut work is made. An adverse microclimate (see), noise (see), the increased content in air of a working zone of various chemical substances can significantly reduce it.

Modern problems of physiology of work. The present stage of development of the national economy is characterized by transition to complex automation and mechanization of production. At the same time along with increase of number working, work to-rykh is followed by intellectual and nervous tension, there is a large number of workers, work to-rykh is characterized by forced rate and a rhythm, repeated repetition of uniform actions.

The major factors of labor process influencing a functional condition of an organism and health of working are: in the same way repeating local muscular tension, long preservation of a forced working pose, a monotonia, nervous and psychoemotional tension. Impact of the specified factors on a human body can amplify due to insufficient physical fitness, the cut is one of the reasons a hypokinesia.

High tension in the course of different types of work can pass into the overstrain which is characterized by development of an adverse functional condition of an organism, boundary between norm and pathology.

Adverse influence of an overstrain on health can be shown in three main directions: an overstrain of a ledge

et as a direct etiol. factor of emergence various nozol. forms of occupational diseases (see. Occupational diseases); the overstrain can be one of the risk factors promoting developing of diseases (psychological, cardiovascular, etc.); reducing body resistance to various adverse effects, the overstrain can promote increase in frequency of emergence inf. diseases and to an aggravation of a current hron. diseases. The same adverse factors can sio-sobstvovat to operational injuries.

In this regard in problem solving, the Central Committees of the CPSU and Council of ministers of the USSR which are contained in the resolution

1982. «About additional measures for improvement of public health care», optimization and rationalization of factors of labor process, reduction of their intensity in compliance with mental and physical capacities of working has paramount value.

As a result of automation and mechanization of production physical work became easier, the share of the work demanding inclusion in work of groups of large muscles of a body considerably decreased, more often only small muscular groups participate in work, but the number of small muscular efforts for change quite often reaches tens and even hundreds of thousands; with smaller tension the cardiovascular system and system of breath functions, there were energy costs less. The level of physical effeciency of the person is lower, the higher «the physiological cost» of any kind of work and the quicker comes exhaustion (see) even at physically easy work. For the persons leading the slow-moving life, sharp vegetative shifts arising at rather small exercise and nervous tension are unusual and demand very big tension of all regulatory processes.

Broad use of the conveyor, line and mechanized lines, considerable crushing and simplification of operations, performance to-rykh demands simple uniform movements, is accompanied by monotony of work and low energy consumptions. At such kind of activity in structure fiziol. changes the leading value gets decrease in functional activity of c. N of page, leading to lowering of the level of wakefulness.

The decrease in level of wakefulness developing in the course of monotonous work is overcome due to considerable strong-willed efforts that under adverse circumstances can promote emergence of various neurotic states.

Methods of a research. Under the influence of production activity are applied to assessment of changes of a functional condition of an organism standard in physiology and functional diagnosis (see) methods of a research. The choice of specific methods depends on research problems and features modern the prof. of activity. The first stage of researches in the area F. t. detailed assessment of character of the prof. of activity working i.e. drawing up a profes-siogramma — detailed registration of working conditions and the analytical description psikhofiziol is. functions of an organism at this type of work. Researches of a functional condition of the organism working are made or once, or throughout a shift. Particularly important time overseeing by duration of separate operations, pauses, idle times, etc. becomes. On the basis of these data define percent of working loading, change of working capacity in time, stability and success of work in general.

Various tests (alphabetic, digital, with Landolt's rings) for check of stability of attention and scoping of the processed information, tests for definition of stability of memory were widely adopted. Assessment of a functional condition of c. N of page make by means of an electroencephalography (see), determine a condition of analyzers by the usual methods applied at a research of sense bodys of the person. At a research of the visual analyzer (see) define contrast sensitivity, stability of clear vision, volume of accommodation, etc. The condition of the acoustic analyzer (see) is estimated by definition of a threshold of acoustical feeling, differential thresholds, etc. Functions of a motor analyzer (see) estimate on thresholds of muscular and joint sensitivity, excitation thresholds and lability. At a research of physical work widely use dynamometry (determination of force and endurance of muscles), an electromyography (see). If necessary estimate various functions of external respiration. Much attention is paid to a research of a functional condition of cardiovascular system. Implementation of the COMPUTER gave the chance to pass to the detailed mathematical analysis of changes of a heart rhythm throughout a shift. An electrocardiography (see), a polycardiography (see), a reografiya (see), a pletizmografiya (see), registration of a tone of vessels, rate of volume flow of a blood-groove, distensibility and capacity of veins, venous pressure, etc. are more and more widely applied. For assessment of the hidden changes in cardiovascular system and its functional reserves use various functional trials: definition of the general physical effeciency, the maximum oxygen consumption, orthotest, different types of tests with the dosed exercise stresses (static character, on the stationary bicycle, the tredbena, steptest, test to Martina, etc.).

Physiological optimization of labor processes. Among actions on fiziol. the correct work-rest schedule is important rationalization of labor processes, under the Crimea understand the system of creation of the periods of work and rest providing them the optimum duration, contents and sequence.

The modes can be daily, week and annual. In order that the short-term regulated breaks in work entered into the mode of the working day were effective, they need to be organized before emergence of exhaustion in working. Depending on the nature of work during breaks workers can passively have a rest, carry out specially picked up physical exercises, be engaged in self-massage (see Massage, hygienic massage), auto-training (see Psychotherapy, an autogenic training), to be exposed to any activating procedures in special rooms for psikhol. unloadings, etc.

An effective remedy of increase in labor productivity is the production esthetics (the correct coloring of production rooms and the equipment, beautiful and rational overalls, functional music, etc.), directed to creation at the person of good mood, decrease in fatigue, reduction of a possibility of traumatism (see an industrial art). To the same purpose serves actions of the ergonomic plan (see Ergonomics).

At types of work with low level of an exercise stress the increasing attention is given to use of means of physical culture (see Physical culture and sport).

Physiological bases of the rational organization of rest. Working capacity is defined both by working conditions, and conditions of rest (see). During rest changed in the course of work fiziol. indicators shall be returned to initial level. This period is called a phase of recovery or a restitution. Its duration for different functional systems is various and is defined by the nature of the previous activity. So, after local static work heart rate and ABP are returned to initial level within 1 — 2 min.; changes in neuromuscular system last much longer therefore total time of rest by 3 — 4 times exceeds duration of the previous work and can reach 30 — 40 min. After hard rhythmic work the long time remains strengthened oxygen consumption. Especially long after hard work shifts in quantity and structure of leukocytes, activity of hormones, the maintenance of a glycogen in muscles are recovered.

To the USSR along with mikroiauza for rest, throughout a shift several regulated periods of rest with complete cessation of work for

5 — 15 min. are entered. At nek-ry types of work (hard physical work, work in the conditions of the elevated temperature of air, work at height, etc.) more frequent and long breaks are possible. Rest can be passive and active. Active recreation includes various forms of activity different, however, from the main work. It is shown that active recreation leads to more bystry maintenance, than passive. I. M. Sechenov's doctrine about active recreation became a scientific basis of production gymnastics (see Gymnastics, production gymnastics). Rest after the working day shall recover forces of working completely. The night dream (see) sufficient duration is of great importance for maintenance.

Exercise in the course of labor training. The most important factor of steady increase in working capacity are exercises in this form of activity (see the Training). Fiziol. a basis of effectiveness of exercise in the course of labor training is the mechanism of formation of conditioned reflexes (see), a dynamic stereotype, formation of functional system of work.

Process of formation of the most economic and rational working actions takes place a number of stages, each of to-rykh has quite certain fiziol. structure. Generalization of nervous processes is characteristic of the first stage. The movements are less organized and held more down owing to insufficiently created control system at this time, the number of muscles, big, often unnecessary for this action, takes part in them.

As a result of the exercise promoting formation of skill, processes of excitement generalizutsya and concentrate, the movements gain big freedom and are carried out at more economic wasting of energy.

During any kind of production activity correctly created dynamic stereotype (see), i.e. the uslovnoreflektorny reaction developed in response to constantly repeating action of the same irritants is important. In this case there is enough one initial irritant (verbal, light, sound, etc.) to use all fixed action program. At the same time uslovnoreflektorny bonds reach a stage of automatism. Thanking to dynamic stereotype the excess movements and excess muscular tension are excluded, programming and correction of the movement is specified and accelerated, by means of a feedback mechanism the current information is specified, associative bonds between reflexes, components a working dynamic stereotype are fixed. Thanks to it professional actions become more economic, less tiresome, are less subject to influence of external irritants, do not demand constant concentration of attention.

Any labor process is impossible without inclusion in system of regulation of various vegetative functions of an organism. At a stage of mastering labor skill and in the course of training of reaction of the blood circulatory system, breath and other systems are inadequate to intensity of the performed work. However in process of formation of a dynamic stereotype and adaptation to a type of work the complete system of self-control of all set fiziol forms. the processes providing successful and economical implementation of labor actions. Therefore, in the course of exercise and training in an organism of working there is a number of the adaptive changes providing increase in intensity of work, increase in its efficiency, long maintenance of high performance. Along with it as a result of exercise functionality of an organism which is especially shown at maximum loads increase in any type of work. Under the influence of physical exercises force and endurance of the working muscular groups can increase twice, indicators of coordination of movements improve, indicators of a difference of size of pulse increase up to work and during work, the stroke and minute output of heart, size of lung ventilation and levels of the maximum oxygen consumption, etc.

In the conditions of systematic work the organism begins to work more economically and gains higher ability to bystry mobilization of the functionality, including and to increase in resilience to influence of various pathogenic factors.

Positive influence of the corresponding labor load of the level of working capacity and health of the person is convincingly shown at noticeable decrease or elimination of this loading.

Effects of an insufficient exercise stress (a hypokinesia and a hypodynamia) were already considered above.

Decrease in size of intellectual loading leads to a memory impairment, attention, a will, logical thinking and other highest mental functions, and also to a nek-eye to adverse shifts in c. N of page of the person.

Feasible rationally organized work is one of the most important and necessary conditions of a healthy lifestyle of the person. Optimum influence of labor process on an organism is noted in that case when in it there are elements of both physical, and intellectual loadings i.e. when it is possible, speaking to I. P. Pavlov's words, «to connect the head to hands».

Feasible work is necessary also for persons of an elderly, including retirement age. Age decrease in level of functional activity of a row fiziol. systems and bodies it can be compensated by activation of these systems at the expense of the corresponding labor loading.

Feasible (on duration, a look and a form) labor loading is a necessary condition of preservation of working capacity at persons of the senior age groups and pledge of an active old age.

Physiological features of work in extreme conditions. Working in unusual (difficult) natural and working conditions quite often come under influence of various environmental factors making an adverse effect on a functional state and operability of an organism. Factors such carry to the category extreme since they can cause overreactions of various systems of an organism owing to absence or imperfection of mechanisms of adaptation (see. Extreme states). It is accurate to draw line between usual and extreme factors quite difficult. Depending on specific features of the person and the nature of its previous activity the same influences at the same time for one people can be usual, for others — extreme.

Work of aircrew belongs to one of the most difficult types of activity. Its feature»:) the high neuroemotional pressure connected with a large number of information, with need of bystry decision-making, influence of unusual natural factors (the lowered partial pressure of oxygen, considerable pressure differences and temperatures, changes of spectral composition of light and visibility) and also with specific influence of the aircraft equipment on an organism (considerable overloads, the increased noise and vibration) is. These factors cause loads of psycho-fiziol. functions of an organism (see. Air medicine, Flights).

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Work of astronauts, in addition to high nervous tension, is characterized also by influence of such factors as lack of gravitation, excessive overloads during accelerations and braking. The changes of a gaseous fluid ionizing and not ionizing radiation (see Medicine space) can be potentially possible influencing factors.

During the work in the conditions of highlands the major adverse factor is the low partial pressure of oxygen leading to decrease in working capacity. Work under water at various depths is connected with impact on an organism of divers of supertension (see. Diving works).

Fiziol. reactions at the people working at Far North are connected with specifics of climatic conditions and extent of adaptation of the person to them.

Development of physiology of work in the USSR. In our country F. t. began to develop intensively after Great October socialist revolution. In 20 — the 30th laboratories of physiology of work in research in-ta of labor protection, occupational health and occupational diseases are created, and also at the large industrial enterprises. Researches on F. t.

L. A. Orbeli, A. D. Slonim, M. I. Vinogradov, etc. were carried out under the leadership of such famous scientists as A. A. U of htomskiya.

Laboratories of physiology of work are created at in-ta of hygiene and labor protection both in our country, and in the majority of the socialist countries. The Soviet scientists have close scientific ties with the of a zaru-bezhnyiya by colleagues and conduct joint researches. The leading place in training but physiology of work occupies departments of physiology and occupational health of medical institutes, departments of physiology of high fur boots and teacher's colleges. Bibliography: Vinogradov M. I. Physiology of labor processes, M., 1966, bibliogr.; About r sh to about in S. I., 3 about -

l and N and 3. M and M about y to and Yu. V N.

Techniques of researches in physiology of work, M., 1974, bibliogr.; M about y to and Yu. V N. Physiological bases of the scientific organization of work, M., 1971, bibliogr.; N and in joint stock company and t and to I A. O. N and To r y and N about Sunday to and I am V. V. Age operability of persons of brainwork, Kiev, 1979; The Guide to physiology of work, under the editorship of

3. M. Zolina and N. F. Izmerov, M., 1983; Sherrer Zh., etc. Physiology of work, the lane with fr., M., 1973.

Yu. V. Moykin. V. I. Tkhorevsky.

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