Physiology, Industrial

a branch of physiology that studies physiological processes in relation to work, that is, the work process in its physiological manifestations. The two main objectives of industrial physiology are to determine the optimum conditions for the performance of a given task in order to achieve high productivity and efficiency, and to devise ways of preventing the adverse effects of various work-related factors. Toward this end, industrial physiology establishes schedules of work and rest that take into account the length, complexity, and importance of a given task, as well as the expenditure of effort it requires.

Industrial physiology ascertains employees’ optimum and maximum capacities for receiving, processing, and transmitting information and devises such procedures as improved methods of presenting visual, acoustic, and other information on signal boards and control panels. Industrial physiology also conducts studies that determine which bodily motions during the work process conserve maximum energy and result in minimum fatigue. Finally, industrial physiology determines, evaluates, and forecasts the physical condition of workers before, during, and after a given task, develops methods and schedules of training and instruction, and establishes means of rationalizing the work process in order to increase efficiency and protect health.

In its efforts to measure susceptibility to fatigue, as well as to determine a drop in efficiency, industrial physiology is closely related to industrial psychology; in its study of the effects on the environment of the body, it is related to occupational hygiene. All three of these disciplines may thus be regarded as components of ergonomics (biotechnology). Occupational hygiene, the scientific organization of labor, and industrial physiology all deal with the important social question of human work.

History. Industrial physiology became an independent discipline in the second half of the 19th century, when the development of industry and of new occupations led the outstanding physiologists H. von Helmholtz, E. Du Bois-Reymond, I. M. Sechenov, and A. Mosso to study fatigue. In 1857 the Polish naturalist W. Jastrzębowski published Characteristics of Ergonomics. Research conducted during the initial (biomechanical) stage of the development of industrial physiology included the studies of M. Rubner on the energy expended during different types of work and those of the German physiologist N. Zuntz and the French physiologist J. Hamard on muscle contraction. Their work was continued in the 20th century by the German physiologist E. Atzler, who formulated a principle of elementary units into which any muscular activity can be divided. At this time it became evident that a comprehensive study of man’s relations to all instruments of production was needed. In the 1920’s and 1930’s, muscular activity was studied at the Institute of Industrial Physiology in Dortmund, Germany, the Institute of Labor in Kurashiki, Japan, in a laboratory in France for the study of various occupations, and in a number of universities in Great Britain and the USA.

Aspects of industrial physiology studied in the 1970’s included maximum work capacity (D. Meister in the USA and K. Murrell and A. Chapanis in Great Britain), the physiological characteristics of operations performed by skilled workers (Z. Jeton in Poland), and the psychological factors involved in various types of work (J. Piaget in Switzerland and C. Hall in the USA).

In the USSR, the focus on the study of muscular activity gave way to comprehensive study of the work process as early as 1920. Important contributions in this area were made at the Central Institute of Labor of the All-Union Central Council of Trade Unions, founded in 1920 by A. K. Gastev. Research at the institute was conducted by physiologists, hygienists, psychologists, and sociologists; among them were Gastev, S. G. Gellershtein, M. I. Vinogradov, A. D. Slonim, and N. A. Bernshtein.

With the development of the automation of production, studies were made of industrial physiology in relation to skilled work and to management factors. Research focused mainly on the central nervous system and the sensory organs. The studies of N. V. Zimkin, I. S. Kandror, Z. M. Zolina, and V. V. Rozenblat analyzed work performance and the factors involved in the initiation of tasks. Studies by V. I. Zinchenko, G. M. Zarakovskii, and B. F. Lomov presented detailed descriptions of work performance in various areas.

Aims and methods. Industrial physiology studies a number of physiological processes occurring during work, for example, respiration, blood circulation, higher nervous activity, digestion, and sensory and motor processes, as well as environmental factors conducive to satisfactory work performance. Methods of measuring physiological processes include electrocardiography, recording the pulse, and measuring the blood pressure, the rate and depth of respiration, and the amount of oxygen taken in and of carbon dioxide exhaled. Changes in the rate of perspiration under various conditions are determined, and tests are made of sight and hearing.

Other methods calculate the energy required to perform given tasks and determine the precision, speed, coordination, and sequence of work-related motions. In addition, such psychological factors as memory, attention span, and emotional reactions are measured. The interdependence of these factors is studied, as well as their relationship to efficient work performance. In this comprehensive approach, studies are also made of the relationship of workers to the instruments of production and to the results and objectives of the work process. The effects of environmental factors on health and efficiency are studied as well.

Industrial physiology makes use of data derived both from laboratory tests and from tests conducted during the actual performance of tasks on the job. In the laboratory method of testing, certain work-related conditions are simulated and studies are made of their effect on overall work performance or on individual elements of work performance. Tests conducted during the actual performance of work study all the factors that affect a worker’s performance and his psychological and physiological state.

The most common method used to study work performance is through analysis of the organ systems that maintain homeostasis in the body, that is, a steady state of the internal environment and of the functioning of the body’s organs and systems under changing conditions. Homeostatic regulation involves the organism’s steady quantitative and qualitative response to changing external and internal conditions. Such regulation may occur at different levels and may involve simple or complex internal systems and different combinations of their functions. For example, a number of physiological mechanisms maintain a constant supply of oxygen for the body’s cells; these mechanisms alter their activity in accordance with the organism’s needs by changing such factors as the heartbeat or the lumen of the blood vessels.

Industrial physiology studies four states of homeostatic regulation: (1) rest (the body’s readiness for work), (2) the transition from rest to the expenditure of effort (intensification of existing forms of regulation), (3) the transitional state during the alteration of homeostasis (new bodily processes become involved in regulation), and (4) the transition to a gradual breakdown of the existing homeostatic structure as an integrated system. For example, when exertion intensifies, the heartbeats become stronger and more frequent, the blood vessels of the muscles dilate, and the blood vessels of the digestive system and skin constrict. Fluid from the cells enters the vessels, and an increased number of red blood cells emerges from the spleen and liver. An increased number of fibers in the muscles contracts, constricted vessels in the skin dilate, and perspiration intensifies. The need of the tissues for oxygen decreases and the oxygen debt increases as homeostasis is reestablished.

If the physical strain is excessive, the vessels dilate paralytically and do not react to the controlling nerve impulses. Respiration and blood circulation become uncoordinated, the blood circulation in the brain is impaired, and cardiac insufficiency and unconsciousness result owing to the loss of homeostatic regulation. A knowledge of these factors is essential for establishing standards of hygiene, determining the strenuousness of a task and its potential for injuring the body, and establishing schedules of work and rest.

One of the main concepts used in industrial physiology is that of the body’s functional state, that is, the complex of those functions and qualities that directly or indirectly constitute an individual’s work capacity. Analysis of the dynamics of homeostatic regulation leads to the identification of two types of functional states: adequate mobilization and dynamic displacement. Adequate mobilization is typical of the well-trained worker in good physical condition and is the result of a state of tension or of a partial reestablishment of homeostatic regulation assuring fitness for a given task. In dynamic displacement there is a change in homeostatic regulation or a loss of such regulation, resulting in impaired coordination, lowered efficiency, or loss of the ability to continue work. Dynamic displacement occurs under extreme conditions of fatigue, hunger, or thirst.

Another important concept of industrial physiology is that of work expenditure, that is, the expenditure and potential replenishment of the physiological reserves consumed during a task, even under optimum conditions. Any physical exertion results in a loss of energy owing to the consuming of the body’s reserves, to structural changes in the muscle fibers, to the decrease of glycogen, sodium salts, potassium salts, and calcium salts in these fibers, and to the appearance of incompletely oxidized metabolites in the blood. Fatigue is one of the consequences of work expenditure. Industrial physiology studies ways of reducing work expenditure through efficient organization of the work process.

An important practical task of modern industrial physiology is to evaluate various occupations in terms of physiological and hygienic factors. Such evaluations calculate the complexity, strenuousness, and potential for injury of the work involved, and are established for work in industry, agriculture, transport, and many other areas. Particular attention is devoted to work on assembly lines, where monotony is an important factor: in such work, the same motion or group of motions is repeated for an extended period of time, or the worker receives a control signal that is always identical.

The data obtained by industrial physiology are used both to organize the work process and to devise methods enabling workers to adapt easily to new conditions, for example, in underdeveloped regions such as the Arctic and Antarctic, in deserts, at high altitudes, and in outer space. Industrial physiologists also deal with problems arising from the development of automatic control systems and of complex mental tasks. For example, mental fatigue, sensory deprivation, and sensory satiation result from exposure to intense, insufficient, or excessive stimulation, respectively, of the sensory organs. This causes a decrease or a marked increase in the general tone of the central nervous system. Insufficient motor activity (hypodynamia), abnormally decreased muscular activity (hypokinesia), and severe mental stress are among the urgent problems faced by industrial physiology.

In the USSR, research on industrial physiology is conducted at the Moscow Institute of Occupational Hygiene and Occupational Diseases of the Academy of Medical Sciences of the USSR, at the Central Research Institute for Labor Protection of the All-Union Central Council of Trade Unions, and at institutes of hygiene and labor protection in Leningrad, Sverdlovsk, Donetsk, Gorky, Kiev, Tbilisi, and other cities. Research on industrial physiology is also conducted at the All-Union Institute of Industrial Design, at the Institute of Psychology of the Academy of Sciences of the USSR, at the Institute of Labor of the State Committee on Labor and Social Problems of the Council of Ministers of the USSR, at Leningrad State University, and at Moscow State University. Industrial physiology is studied within the framework of research on biotechnology. All-Union and republic-wide conferences on industrial physiology are held regularly; in addition, labor congresses organized by UNESCO deal with aspects of industrial physiology. Research on industrial physiology in the USSR in coordinated by the Council for Applied Human Physiology of the Presidium of the Academy of Sciences of the USSR.

Studies on industrial physiology in the USSR are published in the journals Fiziologiia cheloveka (Human Physiology, since 1975), Voprosypsikhologii (Problems of Psychology, since 1955), and Gigiena truda i professional’nye zabolevaniia (Occupational Hygiene and Occupational Diseases, since 1957) and in the series Ergonomics, published by the All-Union Institute of Industrial Design. Studies on industrial physiology are also published in such foreign journals as Ergonomics and Human Factors (Great Britain).