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In the age of globalization, a worldwide movement towards more networked organization structures and fast moving societies is linked to an increase in responsibilities and workloads for many employees. The resulting demands may lead to psychological and physical health problems . This is why there is a growing need to focus on job demands and their associated outcomes, such as worker health, well-being and performance. The following article provides an overview on relevant demands that are typical in the world of work today and their relationship with health outcomes and security at the workplace.
Job demands are all physical, psychological, social or organizational aspects of a job that require continuous physical and/or psychological (i.e., cognitive or emotional) effort . A job demand may lead to positive as well as negative outcomes depending on the demand itself as well as on the individual’s ability to cope with it. Positive responses may be motivation, stimulation or job-satisfaction while negative responses can be depression, anxiety or burnout. Job demands have been identified as one of the most common sources of work-related stress . Long work hours and demanding work shifts, high time pressure, ergonomic problems and unpleasant physical conditions, for example, have a high risk of leading to stress and negative long-term consequences. The negative short- and long-term effects of such demands may be buffered by job resources like control over the work process or just gratification for achievements.
Job demands can be characterized in several categories, and in a variety of different ways. But it is important to note that these categorisation systems are not discrete and, therefore, are inter-related in their meaning to a certain degree . Generally speaking, four types of job demands can be distinguished: quantitative demands (e.g. time pressure or the amount of work); cognitive demands that impinge primarily on the brain processes involved in information processing (e.g. the difficulty of the work); emotional demands which refer primarily to the effort needed to deal with organizationally desired emotions during interpersonal transactions; or physical demands that are primarily associated with the musculoskeletal system (i.e. motoric and physical aspects of behaviour (e.g. dynamic and static loads)) .
The Ergonomic principles defined in the ISO 10075  classify four main categories of sources of job demands, including: task requirements, work equipment, physical work environment, social and organisational factors. Task requirements include all factors related to job content and control, workload and work schedule (e.g. working rotating shifts or permanent night work, irregular work schedules, role ambiguity and lack of stimulating work). Work equipment compromises of all factors related to work equipment and factors related to ergonomic workplace facilities. Physical work environment includes lightning, noise, climate conditions, vibration, weather conditions and smell. Social factors are for instance relationships (e.g. among colleagues or among employee and superior), team structures, social contacts (e.g. isolated work places, customer relations) and conflicts. Organisational factors are, for example, cultural standards, structure of communication, organisational principles, and leadership style.
Cox and Griffiths  describe a more detailed classification of job demands. They differentiate between the following eight aspects: Job content, workload and work pace, work schedule, control, environment and equipment, organisational culture and function, interpersonal relationship at work, role in organization, career development, and home-work interface. Broadly, job content refers to the lack of variety or short work cycles, under use of skills, fragmented or meaningless work, high uncertainty, and frequent contact with the public. Workload and work pace refers to high levels of time pressure, work overload or under load, machine pacing, continually subject to deadlines. Work schedule includes shift working, night shifts, unpredictable hours, inflexible work schedules, long or unsociable hours. Control is, for example, a lack of control over workload or pacing or low participation in decision making. Environment and equipment include inadequate equipment availability, suitability or maintenance; poor environmental conditions (such as, lack of space, poor lighting or excessive noise). Organizational culture and function comprise of poor communication, lack of definition of organizational objectives, low levels of support for problem solving and personal development. Interpersonal relationships at work describe social or physical isolation, interpersonal conflict, lack of social support, poor relationships with superiors, bullying or harassment. Role in organization/ Career development includes role ambiguity, role conflict, and responsibility for people, career stagnation and uncertainty, job insecurity, under promotion or over promotion, poor pay, and low social value to work. Last, but not least, home-work interface refers to conflicting demands of work and home and low support at home and dual career problems.
|General classification||ISO 10075||Cox and Griffiths|
|Quantitative demands||Task requirement||Job content|
|Cognitive demands||Work equipment||Workload and work pace|
|Emotional demands||Social factors||Work schedule|
|Physical demands||Organizational factors||Control|
|Environment and equipment|
|Organizational culture and function|
|Interpersonal relationships at work|
|Role in organization Career development|
Table 1 provides a summary of the different classification of job demands. As explained above these categories of classification of job demands are not discrete. For example, the categories job content, workload and work pace, work schedule and control from Cox and Griffiths are combined in the category task requirement in the ISO classification, which is, in turn, recovered in quantitative and cognitive demands in the general classification. Organizational culture and function together with role in organization and career development are regarded in organizational factors. Environment and equipment includes the same aspects as physical work environment and can be put on a level with physical demands. The table gives an example of the broad variety of ways to classify job demands.
“Strain is defined as the potential psychological, physical, and behavioural outcome of perceived mental workload." . When workers are confronted with job demands they may experience mental strain as a consequence . Mental strain is not negative itself, but it may lead to negative consequences, such as: impairments of mental or physical health. These negative consequences will only become apparent when the perceived demands imposed by the job do not match the perceived ability or qualification of an employee or worker . For example, if an employee is demanded to handle toxic materials, but doesn’t know how to protect himself appropriately he or she will suffer from fear or stress. It is important to take into account that the effects of mental strain can either be facilitating or impairing. Furthermore, a distinction has to be made between short term and long term consequences of mental strain.
Facilitating effects (short term)
The short term facilitating effects of mental strain are warming-up-effects and activation. The warming-up effect is a common result of mental strain. After the beginning of a task the warming up effect leads to a reduction of effort, which is required to implement or carry out the task. Activation is an inner state of a different level of mental and physical functionality. Mental strain leads according to length and intensity to various levels of activation. The ideal level of activation, which ensures the highest level of functionality, should not be too low or too high. A sudden enhancement of mental strain may lead to an adverse over-activation .
Facilitating effects (long term)
The long term facilitating effect of mental strain is, for example, the training effect. Training is a development of psychological and physical skills established by an outlasting change of the individual efficiency, caused by learning processes concerning the recurrent coping of risk factors at work. Well-being and health-maintenance are further effects .
Impairing effects (short term)
According to ISO 10075 short term impairing effects of mental strain are mental fatigue, monotony, reduced vigilance and mental satiation. A future version of the ISO will also include stress as a short term impairing affect.
Mental fatigue is the temporary impairment of mental and physical functional efficiency, depending on the intensity, duration and temporal pattern of the preceding mental strain .
Monotony is a slowly developing state of reduced activation that may occur during long uniform, repetitive tasks or activities; and which is mainly associated with drowsiness, tiredness, decrease and fluctuations in performance, reduction in adaptability and responsiveness, as well as an increase in variability of heart rate .
Reduced vigilance is a slowly emerging state with reduced signal detection performance at observation tasks (e.g. radar or instrument panel observations). The impact is very similar to monotony .
Mental satiation is a nervous and unsettled state, containing a strong emotional rejection towards a repetetive task or a situation that creates a feeling of “making time" or “not getting anywhere". Additional symptoms may be anger, decreased performance, and/or feelings of tiredness, and a tendency of withdraw .
Impairing effects (long term)
The extent of long term, impairing effects of mental strain ranges from the domain of mental health problems to more serious mental disorders, such as: clinical depression or anxiety . Furthermore burnout is predicted, which in turn may lead to various negative outcomes such as physical illness, labour turnover, absenteeism, and early retirement. Other organisational outcomes of mental strain include: decreased performance, increased rate of accidents and an increased likelihood of looking for alternative employment . For example, a research study with transit operators has suggested that workers with high time pressure in their jobs may be four times as likely to have an accident. In periods of increased strain individuals may enhance their smoking and consumption of alcohol .Eating disorders, family problems and violence are further examples for impairing long term effects .Moreover impairing long term effects of mental strain are associated with increased risk of sleep disturbance, infectious disease, musculoskeletal complaints, asthma, suppressed immune functioning, the risk of stroke , elevated blood pressure, hypertension and coronary heart disease .
As mentioned before the aim of creating healthy workplaces is to eliminate risks, but not to reduce job demands to a minimum. However, looking at demands is not enough, when the health of workers is regarded. In addition the presence of resources is also important as they will help employees to handle their job and life stressors .
Job resources contain all physical, psychological, social, or organizational aspects of a job that either reduce job demands and the associated psychological and physiological costs, are functional in achieving work goals or stimulate personal growth, learning and development . Just as job demands, job resources basically comprise cognitive, emotional and/or physical components. Cognitive job resources are, for example, handbooks but also colleagues providing information, whereas emotional components embrace colleagues providing sympathy and affection. Ergonomic aids are ranked on the physical component of job resources . Other examples for job resources are internal personal factors and characteristics such as hope, self-efficacy and optimism . Several studies have shown that job resources have a stress-buffering effect and particularly have motivational potential when job demands are high . So job resources are conceptually similar to coping options; they can mostly be conceptualized as a kind of energetic reservoir that can be tapped when the individual has to cope with stressful stimuli.
The resources of individuals need to be strengthened to enable them to deal with stressors at work. High job demands can result in excessive mental strain, unless workers have sufficient and corresponding types of resources to deal with their demanding work  . The idea of specificity and match, means that workers who are confronted with high physical job demands (e.g., moving heavy objects) are least likely to experience mental strain if they have access to physical job resources (e.g. a trolley). Cognitive job resources (such as, information from a handbook, training, information from colleagues and supervisors) may moderate cognitive demands, like solving complex problems. Finally, workers who are faced with high emotional demands, like taking care of dying patients, are least likely to experience excessive mental strain when they are able to go back to emotional job resources (e.g., support from colleagues). As a result, people are generally inclined to use cognitive job resources to deal with cognitive job demands, emotional job resources to deal with emotional job demands, and physical job resources to deal with physical job demands .
Job resources can be influenced by the workplace and are essential to well-being, which is why they should be incorporated in measures of prevention. Measures of prevention may be divided into three types: primary, secondary and tertiary preventive measures .
Primary prevention interventions include reducing physical-environmental and psychosocial conditions conducive to stress and strengthening organizational resources (social support, and control), as well as individual resources (qualification, fitness, coping abilities etc.) . The OSH framework directive introduces the principle of risk assessment and defines its key elements (e.g. hazard identification, worker participation, introduction of adequate measures with the priority of eliminating risk at source, documentation and periodical re-assessment of workplace hazards). Practical experience shows that such approaches may be developed best in workshops that include employees and/ or their representatives . Measures that will be agreed on may, for example, contain ergonomic redesign of work equipment, freedom to take breaks when necessary or restructuring work tasks at particular work places. Individual resources may be increased by offering skill or stress management trainings, exercise programmes or help at keeping up work-life balance (e.g. flexible working time, reduced working hours, switch from full-time to part-time employment, subsidised childcare).
The overall goal of primary prevention is to avoid the impairing effects mentioned above. Specific design guidelines for measures of prevention should take into account the effects, which are intended to influence fatigue, monotony, vigilance or satiation . For example the enhancement of intensity and duration of workload exponentially leads to fatigue. This is why the duration of working time should match the intensity of workload. In this case a physical job resource is for instance a rest time between sequential working days or working shifts. The rest time needs to be long enough to ensure an entire recovery of fatigue. A further job resource is the employees’ control of their working conditions . If the employees’ control is high, they are able to arrange their rest time autonomously; which will help to avoid impairing effects like fatigue. To get emotional support from colleagues in terms of encouragement and sponsorship to deal with emotional demands (such as, taking care of dying patients), a harmonic, conflict-free relationship between employees’ must be reliable. Role ensures that there are no conflicting roles and that employees understand their role within the organization and change includes the management and communication of organizational change (large or small). The challenge is to motivate organizations to investigate into primary prevention programmes even when there is no evidence for health restrictions or illness so far.
Secondary prevention addresses those workers that show first signs of negative health implications. Its aim is to prevent exacerbation of the symptoms. In opposite to primary prevention secondary preventive measures concentrate on individuals and their specific job situation. When a worker shows first signs of an illness, responsible persons in the organization have to figure out if work demands are related to the health problems or if the individual skills of the worker may be enhanced . As a result either demands need to be changed (e.g. organizational changes or changes in task distribution) or employees need to be strengthened in their resources to be able to deal with the demands.
Finally, tertiary prevention focuses on employee assistance . The goal is to heal those who have suffered long-term negative effects associated with work . It is also important to avoid further impairing effects. Employee assistance programmes are addressing e.g. drug abuse, personal crises, marital and family problems and with a broader perspective impending retirement and relocation . In the context of occupational integration management demands are adapted to individual abilities. Nevertheless at this point poor health and well-being is already associated with lower productivity and increased sickness absence need to be expected.
On the basis of the age of globalization, job demands and their consequences for employee’s health and the job productivity gain more and more importance. In summary, this article integrates job demands into the context of work related stress and the concept of mental workload and mental strain. An overview of all potentially stressful job demands shows the variety of ways to classify job demands. Summarized job demands include all objective elements in the environment, which effect on the worker’s mental and physical state. If the immediate effect of mental workload is positive (i.e. facilitating effects) or negative (i.e. impairing effects) depends on the individual perceived resources and coping styles of an individual. Job demands can also be regarded as challenges therefore the target is not to reduce but to optimise job demands. Job resources are an important factor to help employees to deal with job demands. They have to be adequate to the job demands (e.g. high job demands require high resources).The support of job resources is considered in primary, secondary and tertiary prevention programs with the goal to balance job demands and job resources, resulting in healthy and productive work environment.
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