Physiology labor activity - a section of physiology devoted to the study of changes in the functional state of the human body under the influence of his labor activity and substantiating the methods and means of organizing the labor process aimed at maintaining high performance and maintaining health.

Main elements of the labor process that affect the functions of human systems and his health are stereotypically repetitive muscular work, a forced working posture; increased load on the visual system; nervous and psycho-emotional stress; monotony (monotony) of working actions; hypokinesia. The totality of the elements of the labor process determines the nature of the work load and, consequently, the level of physiological stress of a working person. Value truedouble load depends not only on the nature of the labor process, but also on the organization of its rhythm, the mode of work and rest of the worker (intra-shift breaks and their filling, one-, two-, three-shift work, shift organization of labor), the influence of adverse factors in the production environment (temperature, pressure and humidity; noise and vibration; poor lighting; exposure to harmful chemicals), the need to use personal protective equipment.

The workload can be addressed to various physiological systems, significantly increasing the level of their functional activity. Depending on the degree of involvement in the process of labor activity of the neuromuscular apparatus or neuropsychic functions, the load is divided into physical and nervously-mental.

The restructuring of physiological functions, which provides the body with the ability to successfully cope with the performance of a given labor task, depends mainly on two factors that change independently of each other: (1) performance a person, that is, the ability to perform work for the maximum possible time without reducing its effectiveness. Efficiency depends on the degree of training and the tendency to this species activity, state environment, human health, employee motivation; (2) efficiency factor, defined as the ratio of the amount of energy spent on external (physical) work

to the value of the total energy consumption of the human body. The lower the efficiency, the greater the stress of the body and the less efficiency.

Intensity of labor activity(the nature of work) determines the state of a person both during and after work. If the intensity of work is not high, then the restoration of energy costs and the functional potential of loaded physiological systems occurs completely during work. With an increase in the workload, the recovery of costs does not have time to occur during work and is transferred to the period after its completion. In this case, at the end of the work period, fatigue(see chapter 27). If the intensity of work is high, and the rest time is sufficient to fully restore all the energy costs of a person, then in the process of recovery not only the initial level of the state of physiological systems is reached, but even some excess of it is noted, that is, there is an effect workout(exercises; see chapter 27).

If after work the rest is not enough to fully restore working capacity by the beginning of the next day, then there is a constant accumulation of fatigue. As a result, every subsequent day the work will become more and more stressful and tiring. With continued work, excessive fatigue develops into overwork, that is, chronic fatigue, not disappearing during normal periods of rest. In the absence of special preventive measures, overwork can lead to penvoltage- an unfavorable functional state of a person, borderline between the norm and pathology. The consequence of overvoltage may be an increase in morbidity, the development of occupational diseases, and a decrease in labor productivity. Hence, the importance of developing physiologically substantiated means and methods to reduce the degree of fatigue of workers in each specific case is obvious.

The whole variety of types of labor activity is usually reduced to several generalized groups that have general classificationsnye signs. There are: (1) labor requiring significant muscle activity (daily energy expenditure 4500-6500 kcal); (2) mechanized forms of labor (energy consumption - 3000-4000 kcal/day); (3) labor associated with semi-automatic and automatic production; (4) labor on conveyor and production lines: (5) labor associated with remote control; (6) intellectual work; (7) camera work.

Depending on the nature of the load, the work performed can be physical or mental. During physical labor allocate dynamic and static work. Dynamic work takes place when, in the physical sense, resistance is overcome at a certain distance. In this case (transition from one machine to another, transfer of the object of labor, movement of control levers), work can be expressed in physical units (kGm, W, J). At positive dynamic work

the muscles shorten and act as an "engine". At negatedbody work (lowering the part on the table, descending the stairs with a load), the muscle, tensing, begins to yield to the weight of the load, that is, it plays the role of a "brake".

static the work is characterized by the fact that both without shortening (isometric mode) and after the initial shortening of the muscle, the working link of the body does not overcome any distance. In a physical sense, this is not work. However, the body reacts to it with changes in physiological functions corresponding to the load (strength of contractions and volume of active muscles). In this case, the work done is measured by the product of contraction force and time.

mental work includes mental and emotional components. The thinking component prevails when the work affects, first of all, the intellectual abilities of a person. Examples are activities that require solving mathematical problems, thinking about the production situation and making a decision, concentrating attention, processing signals when working at control panels. Mental work, in which emotional components predominate, manifests itself in specific, often quite pronounced vegetative reactions (vegetative components of emotions).

The nature and organization of labor activity have a significant impact on the change in the functional state of the human body. Diverse forms of labor activity are divided into physical and mental labor.

Physical labor is characterized primarily by an increased load on the musculoskeletal system and its functional systems (cardiovascular, neuromuscular, respiratory, etc.), which ensure its activity. Physical labor, while developing the muscular system and stimulating metabolic processes, at the same time has a number of negative consequences. First of all, this is the social inefficiency of physical labor, associated with its low productivity, the need for high physical exertion and the need for long-term rest (up to 50% of working time).

Mental labor combines work related to the reception and processing of information that requires the primary tension of the sensory apparatus, attention, memory, as well as the activation of thought processes, the emotional sphere. This type of labor is characterized by hypokinesia, i.e. a significant decrease in human motor activity, leading to a deterioration in the reactivity of the body and an increase in emotional stress. Hypokinesia is one of the conditions for the formation of cardiovascular pathology in mental workers. Prolonged mental stress has a depressing effect on mental activity: the functions of attention (volume, concentration, switching), memory (short-term and long-term), and perception worsen (a large number of errors appear).

In modern labor activity, purely physical labor does not play a significant role. In accordance with the existing physiological classification of labor activity, there are: forms of labor that require significant muscle activity; mechanized forms of labor; forms of labor associated with semi-automatically thematic production; group forms of labor (conveyor line, forms of labor associated with remote control, and forms of intellectual (mental) labor.

Forms of labor that require considerable muscular activity take place in the absence of mechanization. These works are characterized primarily by increased energy costs. A feature of mechanized forms of labor is the change in the nature of muscle loads and the complication of the action program. Under the conditions of mechanized production, there is a decrease in the volume of muscle activity, small muscles of the limbs are involved in the work, which should provide greater speed and accuracy of movements necessary to control the mechanisms. The monotony of simple and for the most part local actions, monotony and a small amount of information perceived in the process of labor leads to the monotony of labor. At the same time, the excitability of the analyzers decreases, attention is scattered, the speed of reactions decreases and fatigue quickly sets in.

In semi-automatic production, a person is excluded from the process of direct processing of the object of labor, which is entirely performed by the mechanism. The task of a person is limited to performing simple operations on the maintenance of the machine: submit material for processing, set the mechanism in motion, remove the machined part. Character traits this type of work - monotony, increased pace and rhythm of work, loss of creativity.

The conveyor form of labor is determined by the fragmentation of the labor process into operations, a given rhythm, a strict sequence of operations, automatic supply of parts to each workplace using a conveyor. At the same time, the shorter the time interval spent by workers on the operation, the more monotonous the work, the more simplified its content, which leads to premature fatigue and rapid nervous exhaustion.

In the forms of labor associated with the remote control of production processes and mechanisms, a person is included in the control systems as a necessary operational link. In cases where control panels require frequent active actions of a person, the worker's attention is discharged in numerous movements during speech-motor acts. In cases of rare active actions, the employee is mainly in a state of readiness for action, his reactions are few.

Forms of intellectual labor are divided into operator, managerial, creative, labor of medical workers, labor of teachers, students, students. These types differ in the organization of the labor process, the uniformity of the load, the degree of emotional stress.

The work of the operator is characterized by great responsibility and high neuro-emotional stress. For example, the work of an air traffic controller is characterized by the processing of a large amount of information in a short time and increased neuro-emotional tension. The work of heads of institutions and enterprises (management work) is determined by an excessive amount of information, an increase in the lack of time for its processing, increased personal responsibility for decisions made, and the periodic occurrence of conflict situations.

The work of teachers and medical workers is characterized by constant contacts with people, increased responsibility, often lack of time and information to make the right decision, which determines the degree of neuro-emotional stress. The work of pupils and students is characterized by the tension of basic mental functions, such as memory, attention, perception; the presence of stressful situations (exams, tests).

The most complex form of labor activity, which requires a significant amount of memory, stress, attention, is creative work. The work of scientists, designers, writers, composers, artists, architects leads to a significant increase in neuro-emotional stress. With such tension associated with mental activity, one can observe tachycardia, increased blood pressure, ECG changes, increased pulmonary ventilation and oxygen consumption, increased body temperature and other changes in autonomic functions.

The energy costs of a person depend on the intensity of muscular work, the information saturation of labor, the degree of emotional stress and other conditions (temperature, humidity, air velocity, etc.). Daily energy costs for mental workers (engineers, doctors, teachers, etc.) are 10.5 ... 11.7 MJ; for workers in mechanized labor and the service sector (nurses, saleswomen, workers servicing machines) -11.3 ... 12.5 MJ; for workers performing medium-heavy work (machine operators, miners, surgeons, foundry workers, agricultural workers, etc.), -12.5 ... 15.5 MJ; for workers performing hard physical work (miners, metallurgists, lumberjacks, loaders), -16.3 ... 18 MJ.

Energy costs vary depending on the working posture. With a working posture sitting, energy costs exceed the level of basal metabolism by 5-10%; with a standing working position - by 10 ... 25%, with a forced uncomfortable position - by 40 ... 50%. With intensive intellectual work, the brain's need for energy is 15 ... 20% of the total metabolism in the body (the brain mass is 2% of the body mass). The increase in total energy costs during mental work is determined by the degree of neuro-emotional tension. So, when reading aloud while sitting, energy consumption increases by 48%, when delivering a public lecture - by 94%, for computer operators - by 60 ... 100%.

The level of energy consumption can serve as a criterion for the severity and intensity of the work performed, which is important for optimizing working conditions and its rational organization. The level of energy consumption is determined by the method of complete gas analysis (the volume of oxygen consumption and emitted carbon dioxide is taken into account). With an increase in the severity of labor, oxygen consumption and the amount of energy consumed increase significantly.

The severity and intensity of labor are characterized by the degree of functional stress of the body. It can be energetic, depending on the power of work, during physical labor, and emotional - during mental labor, when there is information overload.

The physical severity of labor is a load on the body during labor, requiring mainly muscle effort and appropriate energy supply. The classification of labor according to severity is made according to the level of energy consumption, taking into account the type of load (static or dynamic) and the muscles being loaded.

Static work is associated with the fixation of tools and objects of labor in a stationary state, as well as with giving a person a working posture. Thus, work that requires a worker to be in a static position for 10 ... 25% of the working time is characterized as moderate work (energy consumption 172 ... 293 J / s); 50% and more - hard work (energy consumption over 293 J / s).

Dynamic work - the process of muscle contraction, leading to the movement of the load, as well as the human body itself or its parts in space. In this case, energy is spent both on maintaining a certain tension in the muscles and on the mechanical effect. If the maximum mass of manually lifted loads does not exceed 5 kg for women and 15 kg for men, the work is characterized as easy (energy consumption up to 172 J/s); 5 ... 10 kg for women and 15 ... 30 kg for men - moderate; over 10 kg for women or 30 kg for men - heavy.

The intensity of labor is characterized by the emotional burden on the body during labor, which requires predominantly intensive work of the brain to receive and process information. In addition, when assessing the degree of tension, ergonomic indicators are taken into account: shift work, posture, number of movements, etc. So, if the density of perceived signals does not exceed 75 per hour, then the work is characterized as easy; 75 ... 175 - moderate; over 176 is hard work.

In accordance with the hygienic classification of labor (R.2.2.013 - 94), working conditions are divided into four classes: 1 - optimal; 2 - admissible; 3-harmful; 4-dangerous (extreme).

Optimal working conditions ensure maximum productivity and minimum stress on the human body. Optimal standards have been established for microclimate parameters and labor process factors. For other factors, such working conditions are conditionally used, under which the levels of adverse factors do not exceed those accepted as safe for the population (within the background).

Introduction

In the process of evolution, a person, striving to most effectively satisfy his needs for food, material values, protection from climatic and weather influences, continuously transformed the natural habitat and, above all, the biosphere. To achieve these goals, he transformed part of the biosphere into territories occupied by the technosphere.

Technosphere- a region of the biosphere in the past, transformed by people with the help of direct or indirect impact of technical means in order to best suit their material and socio-economic needs.

The technosphere, created by man with the help of technical means, is the territory occupied by cities, towns, rural settlements, industrial zones and enterprises. Technospheric conditions include the conditions for people to stay at economic facilities, in transport, at home, in the territories of cities and towns.

Man is in close connection with the technosphere. This connection is manifested in the processes of human life support in everyday life, social and cultural life, education, sports and, of course, in work.

Labor, as a purposeful process of human interaction with the technosphere, is the object of study of many natural and social sciences: political economy, philosophy, occupational health, ergonomics, sociology, engineering psychology, etc. And above all, labor is the object of study physiology- science that studies the processes occurring in a living organism. This science includes the discipline labor physiology, which studies the patterns of the course of physiological processes and the features of their regulation during human labor activity.

The tasks of labor physiology include the study of physiological processes, i.e., the state and changes in the vital functions of the human body in the course of his labor activity, and on the basis of this, the development of measures aimed at improving efficiency and general vitality and improving the health of workers.

2.1 Fundamentals of labor physiology

In the physiology of labor, a number of problems are studied: training, rational modes work and rest, fatigue, rationalization of labor movements, etc.

The beginning of the study of issues of labor physiology was laid in our country by the works of I.M. Sechenov (1901) on the analysis of the role of feelings in labor. In 1914-1918. labor physiology was defined as an independent discipline and institutes dealing with labor physiology appeared (Moscow, Berlin). A great contribution to the development of physiology was made by domestic scientists: N.P. Pavlov, N.E. Vvedensky, A.A. Ukhtomsky.

At present, in our country, many institutes for the protection and hygiene of labor are engaged in the physiology of labor.

Physiology is a science that studies the processes occurring in a living organism. Physiology is connected with other sciences (physics, chemistry, biology, etc.). Physiology is divided into a number of related disciplines, one of which is occupational physiology.

Physiology of labor - This is a branch of physiology devoted to the study of changes in the state of the human body in the process of labor and the justification of the means of organizing labor that help maintain human performance. In the physiology of labor, a number of problems are studied: training, rational modes of work and rest, fatigue, rationalization of labor movements, etc.

Forms of labor. Classification of labor.

The life of an urbanized person is inextricably linked with the following activities: work in various sectors of the economy, stay in an urban environment, use of means of transport, household activities, active and passive recreation.

The variety of forms of human labor activity is divided into physical and mental labor.

Physical work It is characterized by a load on the musculoskeletal system and functional systems of the human body (cardiovascular, neuromuscular, respiratory, etc.), which ensure its activity.

Brainwork combines work related to the reception and processing of information that requires a predominant tension of attention, memory, as well as the activation of thought processes.

In modern human labor activity, the volume of purely physical labor is insignificant. In accordance with the existing physiological classification of labor activity, there are:

forms of labor that require significant muscle activity. This type of labor activity takes place in the absence of mechanized means for performing work and is therefore characterized by increased energy costs;
mechanized forms of labor. A feature of mechanized forms of labor is the change in the nature of muscle loads and the complication of the action program. Under the conditions of mechanized production, there is a decrease in the volume of muscle activity, small muscles of the limbs are involved in the work, which should provide greater speed and accuracy of movements necessary to control the mechanisms. The monotony of simple actions and the small amount of perceived information leads to the monotony of work and the rapid onset of fatigue;
forms of labor associated with semi-automatic and automatic production. With such production, a person is excluded from the process of direct processing of the object of labor, which is entirely performed by the mechanism. The task of a person is limited to performing simple maintenance operations of the mechanism: supplying material for processing, starting the mechanism, extracting finished products. The characteristic features of this type of work are monotony, increased pace and rhythm of work, loss of creativity;
group forms of labor - conveyor. These forms of labor are characterized by fragmentation technological process for individual operations, a given rhythm and a strict sequence of operations, automatic supply of parts to each workplace using a conveyor. With a reduction in the time of performing operations, the monotony of labor increases and its content is simplified, which leads to premature fatigue and rapid nervous exhaustion;
forms of work associated with remote control. With these forms of labor, a person is included in the management systems as a necessary operational link, the load on which decreases with an increase in the degree of automation of the management process. There are forms of production process control that require frequent human actions, and forms of control in which the operator's actions are episodic, and his main task is to control instrument readings and maintain constant readiness to intervene, if necessary, in the process of managing an object;
forms of intellectual (mental) labor. This labor is represented both by professions related to the sphere of material production (designers, engineers, technicians, dispatchers, operators) and outside it (doctors, teachers, writers, etc.). Intellectual work is characterized, as a rule, by the need to process a large amount of heterogeneous information with the mobilization of memory, attention, and is characterized by a high frequency of stressful situations.

The energy costs of a person depend on the intensity of muscular work, the information saturation of labor, the degree of emotional stress and environmental conditions (temperature, humidity, air velocity, etc.).

The level of energy consumption can serve as a criterion for the severity and intensity of the work performed, which has great importance to optimize working conditions and rationalize its organization.

The hygienic classification of labor (R.2.2.013-94) divides working conditions into 4 classes: 1 - optimal; 2 - admissible; 3 - harmful; 4 - dangerous (extreme). Optimal and acceptable classes correspond to safe working conditions.

Optimal working conditions are determined by optimal standards for microclimate parameters and provide maximum labor productivity and minimum body tension.

Permissible working conditions are characterized by environmental and labor process factors that do not exceed hygienic standards for workplaces.

Harmful working conditions are characterized by levels of harmful production factors that exceed hygienic standards and have an adverse effect on the body of the worker and his offspring.

Dangerous (extreme) working conditions are characterized by levels of production factors that during the work shift pose a threat to life, the risk of occupational diseases.

The manifestation of muscle activity during physical work

Work- this is the purposeful activity of man and, as K. Marx wrote, is "the eternal natural condition of human life."

labor process- this is a coordinated increase in activity, functional capacity of tissues, organs and the body as a whole, regulated by the central nervous system and the cerebral cortex. The external manifestation of the labor process is the muscular activity of a person during physical work.

During physical work, two manifestations of muscle activity are observed:

constant effort without changing the length of the muscle - static work;
variable muscle effort with a change in muscle length and body movement - dynamic work.

Dynamic work is less tiring - there is an alternation of contractions and muscle relaxation. During static work, the muscles are in an unchanged state for a long time - fatigue occurs earlier.

When performing physical work, the work of the muscles is mixed. When the muscles are excited during work, the potential energy of nutrients is converted into work with the release of heat.

Changes in the body during the labor process

In the process of labor, the muscles require an increased amount of oxygen and nutrients (proteins, carbohydrates and fats), and changes occur in the body to support these increased needs: in the blood, in the cardiovascular system and in the respiratory system.

Change in the blood during the labor process

During work, as a result of complex transformations in the muscles, metabolic products are formed - carbon dioxide, water and some salts.

Delivery to the muscles and tissues of oxygen, nutrients and the transfer of metabolic products from them is carried out by the blood.

During work, quantitative and qualitative changes occur in the blood.

Quantitative changes are expressed by an increase in the number of erythrocytes and leukocytes. Erythrocytes are blood cells involved in the transport of oxygen by the blood, and leukocytes are cells that perform a protective role (capture and digest bacteria, produce antibodies that destroy microbes).

Qualitative changes in the blood are an increase in the regeneration of erythrocytes, that is, an increase in their young forms, which give oxygen to the tissues more intensively.

The oxygen carried by the blood from the lungs to the tissues is involved in complex chemical transformations called tissue respiration. During this respiration, along with other metabolic products, carbon dioxide is formed, which, getting into the blood, turns into carbonic acid. When blood enters the lungs, carbon dioxide is released and exhaled with air.

Carbohydrates in the blood are mainly in the form of glucose, which is continuously consumed by body tissues, especially muscles during physical work. When glucose is oxidized in tissues, the energy they need is released.

The product of carbohydrate metabolism is lactic acid.

Changes in the cardiovascular and respiratory systems

When working, one change in the composition of the blood is not enough, it becomes necessary to increase the supply of blood to the muscles - an increase in the speed of its movement, which is ensured by an increase in the activity of the cardiovascular system (increased blood flow to the heart, depending on the intensity of work; greater filling and emptying of the heart; increased contractions heart; an increase in the volume of blood ejected by the heart per minute).

An increase in blood flow to working muscles is also associated with its redistribution in the body. Most of the blood is supplied to the working organs, which is achieved due to the vascular reaction (expansion of some and narrowing of other vessels). In addition, to increase circulating blood, the ability of the vascular system (lungs, skin, liver) is used to store the blood supply in "blood depots" - local dilatations of blood vessels. During heavy physical work, the vessels in which blood is deposited are compressed and supply blood to the general stream.

The main way oxygen enters the body is through the respiratory system. If at rest a person consumes 150-300 cm 3 of oxygen per minute, then during hard work this need increases 10-15 times, which is ensured by an increase in pulmonary ventilation, that is, the amount of air inhaled and exhaled in one minute.

Theories of fatigue

During the labor process, such a state of the body can occur when its performance decreases - fatigue sets in. Fatigue is a state of the body caused by physical or mental work, in which its performance decreases. Feeling tired is one of the signs of fatigue.

There are a number of theories of fatigue, considering one of the causes of fatigue:

accumulation of lactic acid and other metabolic products in the muscles;
decreased performance of peripheral nervous apparatus;
fatigue of the central (cortical) link of the nervous system.

The most correct is the central cortical theory of fatigue during muscular work. According to this theory, fatigue is a cortical defense reaction and means a decrease in the efficiency, first of all, of cortical cells.

Signs of fatigue during physical work

During physical work, fatigue is manifested by three signs:

violation of the automaticity of movement: if at the beginning of work a person can also perform side work (talking, etc.), then as he gets tired, this opportunity is lost, and side effects damage the main job.
violation of motor coordination: when tired, the work of the body becomes less economical, coordination of movements is disturbed, which leads to a decrease in labor productivity, an increase in marriage, and accidents.
violation of vegetative reactions and the vegetative component of movements: profuse sweating, increased heart rate, etc. Vegetative components are processes in internal organs regulated by the central nervous system.

Signs of mental fatigue

During mental work, fatigue appears in the form of shifts in the autonomic system. There are three phases nervous activity:

Equalizing hypnotic phase - a person reacts equally to significant and insignificant events (“it doesn’t matter”).

With the development of fatigue, a paradoxical phase occurs, when a person almost does not react to important phenomena for him, and insignificant phenomena can cause increased reactions (irritation).

If after the first phase a short rest is enough to restore working capacity, then after the second phase a longer rest time is required.

In case of violation of the regime of work and rest, a state of overwork may occur, which is expressed in a decrease in working capacity at the beginning of work.

Overfatigue and chronic fatigue can occur with the appearance of an ultra-paradoxical phase in nervous activity: when a person reacts negatively to what caused him a positive reaction in his normal state, and vice versa.

Ways to improve efficiency

performance - the degree of functional capabilities of the human body, which is characterized by the quantity and quality of work performed in a certain time. The performance of the body decreases over time.

Measures to combat fatigue should be aimed at increasing efficiency, delaying the onset of fatigue and providing active recreation.

To reduce fatigue, the following factors are taken into account:

improvement of the general working environment, sanitary and hygienic working conditions and the environment.
rationalization of labor processes (working area, rational movements, labor mechanization; rational design and arrangement of handles, devices). Here, training and mastering effective skills in work is important.
the correct organization of labor: the gradual entry into work, the rhythm and uniformity of the distribution of work over time, the alternation of work and rest, the change in forms of work. Here, emotional arousal is important: interest in work, setting certain goals; in addition, a temporary change in work operations, industrial gymnastics is useful.
favorable attitude of society towards work.

Recreation principles

The form of relaxation plays an important role in improving performance.

Rest should be active, while respecting the following principles:

apply an average degree of stress and stimuli;
during intensive work during rest, use smaller loads, and during long-term uninteresting work - vice versa;
when resting, strive to excite the antagonist muscles (muscles of the left hand when working with the right hand and vice versa);
use emotions more widely when relaxing.

To combat fatigue, various stimulants are also used:

CHEMICAL - phenamine, pervitin, etc.
HERBAL - preparations of leuzea, golden root, etc.

But we must remember that chemicals cause a number of side and harmful effects: insomnia, loss of appetite, etc.

Thus, the conditions in which a person works affect the results of production - labor productivity, quality and cost of products. Labor productivity is increased by maintaining human health, increasing the level of use of working time, and prolonging the period of active labor activity of a person.

Improving working conditions and its safety leads to a decrease occupational injury, occupational diseases, which preserves the health of workers.

2.2 Comfortable living conditions

The technosphere, created by the hands and mind of man, designed to satisfy his needs for comfort and safety as much as possible, in many respects did not justify the hopes of people. The biosphere in many regions of the planet began to be actively replaced by the technosphere, there are few territories left on the planet with undisturbed ecosystems. The emerging industrial and urban environments turned out to be far from the necessary requirements in terms of safety and environmental friendliness. Ecosystems are most destroyed in developed countries: Europe, North America, Japan. Here, natural ecosystems have been preserved mainly on limited areas, they are small patches of the biosphere, surrounded on all sides by territories disturbed by human activity.

In the conditions of the technosphere, negative interactions in the "man-environment" system are characterized as:

comfortable (optimal) when the flows correspond to the optimal conditions of interaction (create optimal conditions for activity and rest; prerequisites for the manifestation of the highest efficiency and productive activity); guarantee the preservation of human health and the integrity of the components of the environment;
admissible , when the flows, affecting a person and the environment, do not negative impact on health, but lead to discomfort, reducing the efficiency of human activity; compliance with the conditions of permissible interaction guarantees the impossibility of the emergence and development of irreversible negative processes in humans and in the environment;
dangerous when the flows exceed the allowable levels and render negative impact on human health, causing long-term exposure to disease, and (or) lead to degradation natural environment;
extremely dangerous when flows high levels in a short period of time, they can cause injury, lead a person to death, cause destruction in the natural environment.

Of the four characteristic states of human interaction with the environment only the first two (comfortable and acceptable) correspond to the positive conditions of everyday life, and the other two (dangerous and extremely dangerous) are unacceptable for the processes of human life, conservation and development of the natural environment.

The conditions in which a person works affect the results of production - labor productivity, quality and cost of products. Labor productivity is increased by maintaining human health, increasing the level of use of working time, and prolonging the period of active labor activity of a person.

One of the necessary conditions for a healthy and highly productive work is to provide an optimal microclimate.

Industrial premises- these are closed spaces of the production environment in which people constantly (in shifts) or periodically (during the working day) carry out labor activities related to participation in various types production, in the organization, control and management of production. Inside the production premises there is a working area and workplaces.

Working area called the space (up to 2 m) above the floor or platform, on which there are places of permanent or temporary stay of workers. Part of the working area, which is a place of permanent or temporary stay of workers in the process of labor activity, is called workplace.

Microclimate of industrial premises- this is the climate of the internal environment of these premises, which is determined by the combinations of temperature, humidity and air velocity acting on the human body, as well as the temperature of the surrounding surfaces.

Table 2.1: Comfortable (optimal) conditions are:

No. p / p	Indicators	Meaning
	Air temperature at the workplace, ?С:* • Indoors during the warm period • Indoors during the cold period • Outdoors during the warm season • Outdoors during the cold season

	Relative humidity, %
	Air speed, m/s:
	Toxic substances (multiplicity of MAC exceedance)
	Industrial dust
	Illumination, the multiplicity of exceeding or reducing the norm according to SNiP
	Vibration, the level of oscillatory speed does not exceed the remote control	multiplicity below the remote control
	Noise, sound level dB
	Value physical activity:
	• General, performed by the muscles of the body and legs, kgf/m per shift • Regional, performed by the muscles of the shoulder girdle, kgf/m per shift • The working posture is free (change of posture "Sitting - standing"), the body and limbs are in a comfortable position when moving a load weighing up to 5 kg.	at the discretion of the employee
	The value of neuropsychic stress:
	• Duration of concentrated observation in % of working time per shift • Number of important objects of observation • Number of movements per hour
	Visual intensity:
	• The size of the object of distinction, mm. • Accuracy of visual work • Category of visual work according to SNiP
	Monotone:
	• Number of receptions (elements in operation) • Duration of recurring operations

The main factor in creating an optimal microclimate is air temperature(the degree of its heating, expressed in degrees), which to the greatest extent determines the influence of the environment on a person.

Under natural conditions of the Earth's surface, the temperature of the atmospheric air varies from -88 to +60°C, while the temperature of the internal organs of a person, due to the thermoregulation of his body, remains comfortable, close to 37°C. When performing heavy work and at high ambient temperatures, the human body temperature can rise by several degrees. The highest temperature of the internal organs that a person can withstand is +43°C, the minimum is +25°C.

Air humidity also has a significant impact on microclimate.

Air humidity is characterized by the following concepts:

absolute humidity(A), which is expressed as the partial pressure of water vapor (Pa), or in weight units in a certain volume of air (g / m 3);
maximum humidity(P) - the amount of moisture at full saturation of air at a given temperature (g / m 3);
relative humidity (P) is expressed in %, P=A/P·100%. High relative humidity (the ratio of the content of water vapor in 1 m 3 of air to their maximum possible content in this volume) at high air temperatures contributes to overheating of the body, while at low temperatures it enhances heat transfer from the skin surface, which leads to hypothermia of the body. Low humidity leads to intense evaporation of moisture from the mucous membranes of their drying and cracking, and then to contamination with pathogenic microbes.

Temperature, relative humidity and air velocity are measured at a height of 1.0 m from the floor or work platform when working while sitting, and at a height of 1.5 m when working while standing, and not closer than 1 m from heating appliances and outdoor walls.

To determine the parameters of the microclimate, various measuring instruments are used: thermometers, thermographs, anemometers, psychrometers, etc.

The optimal microclimate for a particular person is determined only on the basis of his subjective assessments. It is well known that the subjective sensation of heat or cold depends not only on climatic conditions, but also on factors such as body constitution, age, gender, severity of work, clothing, etc. Therefore, in practice, we are talking, as a rule, about the ranges of optimal temperatures and air humidity.

Normal thermal well-being takes place when the heat release of a person is completely perceived by the environment. If the body's heat production cannot be fully transferred to the environment, the temperature of the internal organs rises, and such a thermal well-being is characterized by the concept of hot. Otherwise, it's cold.

Thus, the thermal well-being of a person, or the thermal balance in the human-environment system, depends on the temperature of the environment, mobility and relative humidity of the air, atmospheric pressure, temperature of surrounding objects and the intensity of physical activity.

For example, a decrease in temperature and an increase in the speed of air movement contribute to an increase in convective heat transfer and the process of heat transfer during the evaporation of sweat, which can lead to hypothermia of the body. An increase in the speed of air movement worsens health, as it contributes to an increase in convective heat transfer and the process of heat transfer during sweat evaporation.

When the air temperature rises, the opposite occurs.

Microclimate parameters air environment, which determine the optimal metabolism in the body and in which there are no unpleasant sensations and tension in the thermoregulation system, are called comfortable or optimal. The zone in which the environment completely removes the heat generated by the body, and there is no tension in the thermoregulation system, is called comfort zone. The conditions under which the normal thermal state of a person is violated are called uncomfortable. With a slight tension in the thermoregulation system and slight discomfort, acceptable meteorological conditions are established. Permissible values of microclimate indicators are established in cases where, according to technological requirements, technical and economic principles optimal rates are not met.

During production processes, heat is almost always released. Heat sources are furnaces, boilers, steam pipelines, flues and steam. In the warm season, the heat of solar radiation is added.

Man is constantly in the process of thermal interaction with the environment. For the normal course of physiological processes in the human body, it is necessary that the heat released by the body be removed to the environment. When this condition is met, comfort conditions set in and the person does not feel disturbing thermal sensations - cold or overheating.

The release of heat by the human body Q occurs through heat conduction through clothing Q o, convection as a result of washing the human body with air Q k, radiation Q and, heating of exhaled air Q in and due to sweating - evaporation of moisture from the surface of the skin Q use .. The amount of heat given off by each of these pathways, depends on the parameters of the microclimate at the workplace.

Comfortable conditions for the human body are provided subject to the thermal balance

Violation of the thermal balance leads to overheating or hypothermia of the body, which, in turn, leads to disability, fatigue. loss of consciousness and death.

Radiation of heat occurs into the environment if the temperature in it is lower than the temperature of the surface of clothing (+27?30 o C) and open parts of the body (+33.5 o C). At high temperatures (+30 ? 35 o C) of the environment, heat transfer by radiation stops completely, and at higher temperatures, heat transfer goes in the opposite direction - from the surrounding surface to the person. Heat dissipation by sweat evaporation depends on relative humidity and air velocity. The dependence of heat transfer and sweating on air temperature is shown in Fig. 5, a, b.

The amount of heat released by the human body depends on the degree of physical stress and ranges from 75 kcal / h at rest to 430 kcal / h during hard work. For comfortable working conditions, it is necessary that the heat release of the body is equal to its heat transfer, while the temperature of the internal organs of a person remains constant (about 36.6 degrees C).

Rice. 5. Schedule of thermoregulation of the human body depending on the air temperature: a- with heat radiation, b- when sweating: 1-very hard work; 2 - hard work; 3 - work of medium severity; 4 - easy work; 5 - peace.

The body's ability to maintain a constant temperature when the microclimate parameters change and when performing work of varying severity is called thermoregulation.

Thermoregulation provides a balance between the amount of heat that is continuously generated in the body in the process of metabolism, and the excess heat that is also continuously released to the environment, i.e., the heat balance of the human body.

Distinguish between physical and chemical thermoregulation. In the physical - the release of heat from the body to the environment is carried out in three ways:

in the form of infrared rays (at low ambient temperature) radiation; in this case, about 45% of the thermal energy produced by the body is lost;
heating of air washing the surface of the body (convection) - about 30% of heat is lost;
evaporation of sweat - about 13% is lost.

About 5% of the heat is spent on heating the ingested food, water and exhaled air; the rest of the heat is consumed by chemical thermoregulation.

At high air temperatures, the blood vessels of the body surface expand, blood flow increases and heat transfer increases. When the air temperature drops, the vessels on the surface of the body narrow, which reduces blood flow and heat transfer. Thus, for the thermal well-being of a person, a certain combination of temperature, relative humidity and air velocity is important. The normal ambient temperature can be considered 15-25 degrees C.

High humidity (more than 85%) makes thermoregulation difficult due to a decrease in sweat evaporation, and too low (less than 20%) causes drying of the mucous membranes of the respiratory tract. Normal humidity is 40 - 60%.

Relative humidity is the ratio of water vapor content in 1 air to their maximum possible content at a given temperature, expressed as a percentage.

The movement of air in the room contributes to the heat transfer of the body, but at low temperatures is an unfavorable factor. In winter, the air velocity should not exceed 0.3 - 0.5 m/s, and in summer 0.5 - 1 m/s. Reduced body heat transfer can lead to overheating of the body. The high humidity of the air, its immobility and the presence of clothing impervious to air and sweat contribute to overheating - a violation of the body's thermoregulation. The thermoregulation of the body is sharply disturbed at an air temperature above 30 ° C and a humidity of 85% or more, while increasing weakness is observed, headache and heat stroke may occur, which is accompanied by an increase in body temperature (up to 40-41 ° C) and loss of consciousness.

Working area of the premises, types of weather conditions for it.

Sanitary and hygienic requirements (GOST 12.1.005) establish the optimal and permissible standards for temperature, relative humidity and air velocity in the working area of industrial premises.

Work zone - this is a space with a height of 2 m above the floor or platform, on which there are places of permanent or non-permanent (temporary) stay of workers. Optimal conditions ensure the maintenance of thermal equilibrium between the body and the environment, a feeling of thermal comfort.

Periods of the year and categories of work in accordance with GOST 12.1.005

Sanitary and hygienic requirements (GOST 12.1.005) establish the necessary microclimate parameters in industrial premises with considering:

periods of the year:
- cold period with an outdoor temperature equal to +10 ° C and below,
- warm period - above +10 o C;
categories of work - all works subdivided according to severity into three categories:
- light work - category I (energy consumption up to 150 kcal / h - instrumentation);
- medium-heavy work - category II (energy costs from 150 to 250 kcal / h - mechanical assembly, rolling shops);
- heavy work - category III (more than 250 kcal / h - physical stress, carrying heavy loads - more than 10 kg - blacksmith shops with hand forging, etc.).

GOST also establishes requirements for monitoring the content harmful substances in the air of the working area.

Protective measures against heat radiation and cold.

Radiant energy (thermal and solar radiation) has a harmful effect on a person.

Radiant energy is emitted by heated surfaces of steam generators, turbines, steam pipelines, etc. Radiant energy causes skin burns, as well as effects on the entire body, especially on the nervous system.

Measures to protect against human exposure to abnormal meteorological conditions are reduced to maintaining microclimate parameters at a given level through air conditioning, ventilation; from thermal radiation, the following measures are applied: eliminating the source of heat release, protecting against thermal radiation, facilitating the heat transfer of the human body, personal protective measures.

The elimination of heat sources is possible with a change in technology (replacement of fiery furnaces with electric ones), with automation and mechanization of manual labor, reduction in the length of steam pipelines, etc.

Protection against the direct action of radiant energy is carried out mainly by shielding.

Screens are divided into absorbing and reflecting radiant heat. They can be stationary and mobile.

Absorbing screens are made in the form of curtains, shields. Curtains are installed against radiating openings and are made either from small metal chains that reduce the radiant flux by 60-70%, or from a water film that absorbs up to 90% of radiation and transmits visible radiation.

Reflective screens are made of brick, aluminum, tin, asbestos, aluminum foil on asbestos or metal mesh, and other materials. Screens can be single or multi-layered, and the free movement of air between the layers increases the screening efficiency.

Personal protection in hot shops is achieved by protective clothing made of non-flammable, resistant to radiant heat, durable, soft material: cloth, tarpaulin or synthetic linen, chemically treated fabrics with a metal coating.

A suit in the form of overalls is often performed pneumatically with air supplied under it through a hose. Hats made of felt, felt or coarse woolen cloth are used, as well as heat-resistant shoes and mittens.

The eyes are protected from exposure to radiant energy with glasses with light filters: at a temperature of 1800 ° C - blue glasses SS-11, at higher temperatures - dark TC 2, TC 3. The glasses are attached to the visor or headgear fields.

The use of glasses is mandatory, because prolonged exposure to infrared rays (of a certain length - Focht rays) is dangerous for the eyes - they cause eye cataracts (clouding of the lens).

To compensate for the loss of moisture and salts lost during sweating, as well as for the prevention of heat stroke, it is necessary to perform a certain drinking regimen, especially in hot shops.

All enterprises should be provided with high-quality drinking water, the distribution of which should be carried out through fountains, cisterns with nozzles installed at a height of 1 m from the floor, etc.

BJD and ergonomics

BJD is a complex discipline based on data from related sciences, including ergonomics. This term was proposed by the Polish scientist Yastrebovsky in his work "Features of Ergonomics, that is, the Science of Labor" (1875).

Ergonomics studies the functional capabilities of a person in the process of activity in order to create comfortable conditions for his activity.

Ergonomics seeks to adapt technology to man, and the Belarusian Railway, in addition, studies the problems of adapting man to technology, i.e. their compatibility.

Types of human and technology compatibility

There are the following types of compatibility: informational, psychological, social, biophysical, energy, anthropometric and technical-aesthetic.

Informational, psychological and social compatibility

Information compatibility, this is the compatibility of technology with the psychophysiological capabilities of a person.

The operator controls complex systems with the help of controls (buttons, levers, switches), the totality of which forms a sensory field; while the operator observes the readings of instruments, screens, diagrams, listens to the signals, i.e. uses means of displaying information (SDI).

Psychological compatibility takes into account the mental capabilities of a person. Accidents, injuries to a large extent depend on organizational and psychological reasons: low professionalism, neglect of safety requirements, admission to dangerous work of untrained persons or in a state of fatigue.

It is necessary to take into account the peculiarities of the psyche of some people: fear of enclosed spaces (claustrobia), open spaces (agoraphobia).

social compatibility takes into account the relation of a person to a specific social group and vice versa - a social group to a specific person.

Social compatibility is associated with psychological characteristics person, with his behavior in the team.

Biophysical and energetic compatibility

Biophysical compatibility- creation of an environment that ensures high performance and normal physiological state of the operator. This task is aligned with the requirements of labor protection.

This compatibility takes into account the thermoregulation of the human body, which depends on the parameters of the microclimate, as well as the vibroacoustic characteristics of the environment and illumination.

Energy Compatibility- this is the coordination of controls with the optimal capabilities of the operator in terms of applied forces, expended power, speed and accuracy of movements.

Anthropometric compatibility

Anthropometric compatibility- this is taking into account the size of the human body, the possibility of viewing space, taking into account the position (pose) of the operator in the process of work in order to minimize the expenditure of physical strength.

This takes into account the volume of the workplace, the reach zone for the operator's limbs, the distance from the operator to the instrument panel, etc.

When organizing a workplace, the requirements of GOSTs 12.3.002 "Production processes", 12.0.003 "Harmful and dangerous production factors", 12.2.049 "Ergonometric requirements" are taken into account; 12.2.032- workplace standing; 12.2.033 - sitting workplace.

The rational arrangement of the workplace takes into account its optimal layout, the degree of mechanization, automation, the choice of the operator's working posture and the location of the controls for tools and materials.

So, in the conditions of the technosphere, negative interactions in the "human-environment" system are characterized as: comfortable(optimal), admissible,dangerous and extremely dangerous. Of the four characteristic states of human interaction with the environment, only the first two (comfortable and acceptable) correspond to the positive conditions of everyday life, and the other two (dangerous and extremely dangerous) are unacceptable for the processes of human life, conservation and development of the natural environment.

One of the most important elements ensuring the efficiency of human labor activity is the optimization of the parameters of the production environment (microclimate, lighting, etc.).

The industrial microclimate norms are established by the system of labor safety standards GOST 12.1.005-88 “General sanitary and hygienic requirements for the air of the working area”. They are the same for all industries and all climatic zones with some minor deviations. In these standards, each component of the microclimate in the working area of the production facility is separately standardized.

findings

To maintain the health of employees of institutions, workers of economic facilities, it is necessary to correctly take into account the regularities of the daily rhythm of human physiological processes, i.e. provide such parameters that contribute to the best use of production assets and ensure the greatest efficiency of human labor activity.

Therefore, it is necessary to establish an optimal mode of work and rest, and this requires an integrated socio-economic approach. The purpose of this approach is a complete and comprehensive assessment of its optimization in terms of taking into account personal and public interests, the interests of production (organization, institution) and the physiological capabilities of a person.

test questions

Expand the concepts: "Physiology" and "Physiology of labor."
How is human activity divided? Forms of labor.
Hygienic classification of labor.
theories of fatigue. Ways to improve performance.
Recreation principles.
Characteristics of interaction in the system "man-environment".
Comfortable living conditions.
The interaction of the human body with the environment.
Types of compatibility of man and technology.

Bibliography

Life safety: Textbook for students of secondary special. textbook Institutions / S.V. Belov, V.A. Devisilov, A.F. Koziakov and others; Under total ed. S.V. Belova.- 3rd ed., corrected. and additional - M .: Vyssh. school, 2003.- pp. 5-65.
Mikryukov V.Yu. Life safety: Textbook / V. Yu. Mikryukov. - Rostov n/a: Phoenix, 2006.- pp. 217-246.
Revskaya N.E. Life safety. Tutorial SPb.: Publishing House of Mikhailov V.A., 2004 - pp. 7-13.
Hwang T.A., Hwang P.A. Life safety. Series Textbooks and teaching aids. Rostov n/a; "Phoenix", 2003. - pp. 44-145.
Feoktistova O.G. Life safety (medical and biological foundations): Textbook / O.G . Feoktistova, T.G. Feoktistova, E.V. Ekzertseva. - Rostov n / a: Phoenix, 2006. - pp. 173-177.

Physiology of labor - This is a section of general physiology devoted to the study of changes in physiological functions in the process of human labor activity.

Unlike private sections of physiology, this section is a synthetic discipline that studies not so much individual functions as their relationship under workload conditions.

The study of the physiology of labor activity includes two main aspects - theoretical and practical. In the first case, we are talking about the study of the mechanisms of adaptation of physiological functions to the factors of the production environment.

Tasks of practical physiology(which will be of interest to us to a greater extent) - the study of specific types of labor activity, individual professions in order to study their physiological characteristics and substantiate the optimal modes of work and rest.

Physiological characteristics of the labor process - These are the requirements for the functional state of the body, which ensures successful activity.

The most developed and substantiated are the physiological characteristics of the labor process, which determine the severity, tension, harmfulness and danger of labor.

conceptseverity of labor relate mainly to physical labor. This is a characteristic of labor that determines the degree of involvement in the activity of skeletal muscles and reflects the physiological cost of predominantly physical activity. Thus, the severity of labor is determined by ergometric (value of external work) and physiological (energy consumption, activation of cardiac activity, changes in respiratory function) indicators.

Labor intensity - a broader concept. It is determined not only by the intensity of physiological processes during labor activity, but also by the characteristics of the activity structure. The assessment of tension is based on indicators of the intensity and pace of work, informational, motivational and emotional characteristics of the activity.

Harmfulness and danger of work are assessed in terms of injury and morbidity, as well as the probability of the risk of an accident and the concentration of harmful factors.

Modern physiology of labor solves problems of different levels. Among these problems, it should be noted those of a general nature, such as professional selection, diagnosis and prediction of fatigue, management of the functional state, including pharmacological management.

Methods for studying body systems.

For condition assessment motor system The following methods are most commonly used.

muscle strength determined using a dynamometer.

Muscular Endurance is estimated as the maximum time in seconds of holding the effort.

To test the properties of the sensorimotor system to evaluate the position of body parts due to their own mechanisms (without visual control), a technique for determining the accuracy of position reproduction is used.

To assess movement coordination and tremor an arsenal of instruments, usually laboratory-made, is used.

Most often for condition assessment of cardio-vascular system indicators of arterial pressure, pulse and electrocardiogram are used.

For condition assessment respiratory system indicators of pulmonary ventilation (spirometry) and an indicator of blood oxygen saturation (oxygemometry) are used.

For rate status and performance people are increasingly being used psychophysiological methods, in particular, the determination of the time of sensorimotor reactions to light and sound signals allows us to assess the dynamics of the speed of nervous processes, their switching, the level of hand-eye coordination, general level efficiency and activity of the central nervous system, the ability to predict. Methods for assessing the characteristics of attention are implemented in two main directions - test and hardware.

Life safety Viktor Sergeevich Alekseev

21. Physiological basis of labor

Labor is necessary for the optimal flow of biological processes in the body, therefore, it has a great impact on health.

Physical work characterized by severity and is associated with the performance of static and dynamic work, and the mental one is associated with tension against the background of static stress. Physical and mental labor are based on the same central mechanisms. Physical labor is characterized by high energy consumption, oxygen consumption, rapid development of fatigue and relatively low productivity.

Static work is more tedious than dynamic work. During dynamic work, due to the alternation of the processes of contraction and relaxation of the muscles, the latter rest. Contracting skeletal muscles simultaneously act as micropumps, facilitating blood circulation and performing the function of a "peripheral heart". During static work, muscle tension lasts continuously, the vessels in them are constantly compressed, and normal blood circulation is difficult. This leads to stagnation of blood, accumulation in the muscles and in the body of products of incomplete oxidation.

Mental work is one of the most laborious and stressful.

First of all, a clear and precise work of the brain is necessary: attention and memory, which most people consider the main guarantee of success in mental work. Attention has wave-like fluctuations due to natural physiological reasons - a periodic increase in the excitability of the brain is replaced by a decrease in its activity and is associated with the appearance and maintenance of a persistent focus of excitation in one (or several) well-defined centers of the brain. Memory is associated with the preservation of persistent traces of excitation (or internal inhibition) in various centers of the cerebral cortex of the cerebral hemispheres.

With an increase in the severity of physical labor and the intensity of mental labor, oxygen consumption increases. There is a limit to the maximum amount of oxygen that a person can consume - the so-called oxygen ceiling. Usually it does not exceed 3-4 l / min. During the performance of very hard work, the supply of oxygen to the body reaches its limit, but the need for it becomes even greater and is not satisfied in the process of work. At this moment, a state of oxygen deficiency occurs in the body - hypoxia, which becomes a damaging factor. Intracellular oxidative processes and toxic substances are formed - free oxygen radicals that poison the body. If hard physical and mental work continues for a very long time or a person is not accustomed to great physical or mental stress, then his respiratory and cardiovascular systems poorly provide the work of muscles and brain cells. There are mechanisms in the body that prevent the development of such a dangerous condition. There is a decrease in efficiency, fatigue develops. However, if the working capacity does not have time to recover by the beginning of the next working day, overwork develops, accompanied by chronic hypoxia, impaired nervous activity, diseases of the cardiovascular and other systems.

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