Contents   Search publications                     Previous chapter   Next chapter

General health

In addition to the specific effects of VDU work on operators' eyesight, skin, musculoskeletal and reproductive systems, there have also been many reports of a general worsening of VDU workers' health, both physical and mental. Complaints range over a wide area including:

increases in colds, flu and other viral infections digestive and eating disorders angina and other heart or circulatory problems migraine attacks depression irritability exhaustion insomnia sexual difficulties increased dependence on alcohol, tobacco, tea, coffee and tranquillisers increased risk of some types of cancer

Obviously none of these complaints is peculiar to VDU workers, but many of these symptoms are associated with the increased levels of stress reported by many of those who work on VDUs.

Stress

Stress is a condition which can be caused both by physical and psychological factors, and whose effects can be both physical and psychological. Different types of stress can exacerbate each other, so that for example, if the body is recovering from the stress caused by a physical injury, then it is less able to resist infection; both conditions could in turn be aggravated by worry.

A Canadian survey of 79 data entry operators found that 85 per cent experienced work-related stress and there was a very strong association between reported occupational stress and physical health complaints (Pickett and Lees 1991). The researchers concluded that provision of 'ergonomic', adjustable workstations alone will not offer protection against the physical effects of VDU work and that the control and prevention of physical and mental stress complaints must be tackled simultaneously. This finding was confirmed by a three year study of 530 US communications workers. 22 per cent of all the workers had repetition strain injuries even though the workstations studied conformed to physical ergonomic standards.

An important piece of research presented to the 1992 Work with Display Units '92 Conference showed that workers' own impressions of how much stress they are feeling very closely matched stress levels gauged by measurement of peak concentrations of carbon dioxide in exhaled breath (VDT News November/December 1992). (Most people hyperventilate under stress, as a result of which they don't use all the oxygen they take in, and they exhale less carbon dioxide).

The forms of stress which VDU operators may be subjected to include:

Muscular stress

Eye muscles, fingers, hands, wrists, arms, shoulders, back, trunk, and legs are all involved intensively in gazing at the screen, operating the keyboard or supporting the rest of the body in doing so. Both repetitive movements and static loads are involved, all of which create tension and place abnormal demands on the body's resources. This subject is dealt with in detail in Chapter 5.

Environmental factors

Many VDU operators are exposed to stressful levels of noise, for example from the sounds of typing, telephones ringing, opening and shutting of filing cabinets, street noise, the air conditioning system, printers and from the VDU itself, particularly the hum from the cooling fan. Audio typists and telephone sales assistants are also expected to work with earphones. Such workers are subjected to continuous noise, often with a high level of distortion or interference, which may be made worse if they have to turn up the volume to make them audible over high levels of background noise.

As well as noise, many VDU operators experience overcrowding, extremes of temperature and dryness, atmospheric pollution and poor lighting. Detailed recommendations on workplace design are given in Chapter 9.

Hardware and software design

The physical design of equipment which is awkward or uncomfortable to use can be an important cause of stress (see also Chapter 9). So can poorly designed software - particularly that which produces unpredictable delays in response times or unexpected errors, or is used to monitor performance. Payment incentive schemes based on keystroking or error-free operation encourage excessive work speeds with greatly increased stress on the workers involved.

Job design factors

A great deal of stress is caused by the way in which jobs are designed. Monotony, lack of any chance to change either your position or the type of work being done, piece rates, pressure to work fast to meet production targets and the knowledge that the work is being closely monitored can each place the individual operator under strain. If the job includes several of these factors, this strain can quickly become intolerable. Electronic monitoring of workers' performance, which may in turn be linked to payment-by results has been termed a cause of 'undesirable job stresses' by the World Health Organisation (Journal of Occupational Medicine 1989).

The Schedule to the Regulations specifies that:

For many VDU operators the most important job design factor causing stress is lack of control over the job.

Several new studies, including a USA survey of 100 employees conducted over a three year period, have shown that heavy work load, work pressure and lack of support by supervisors are important predictors of stress. However, these factors can change over time, and in the USA study, employees interviewed during the third year said that job security and clear task definition were the most important factors contributing to stress (VDT News January/February 1993).

Throughout this book we emphasise the importance of frequent rest breaks away from the screen. Frequent breaks help to prevent stress. However, some computer systems have been developed which include rest break programs - which force users to take breaks at specific regular intervals. Whilst this might appear to offer the advantage of ensuring that breaks are taken, it also adds to the problem of lack of control over the job. It is preferable for user to have the right to take breaks at their own discretion, before the onset of any discomfort.

Another 'development' which may be advocated by employers is 'stress management'. This consists of a variety of activities and techniques ranging from blinking more often, to yoga, deep breathing to encounter group meetings. Whilst there may be benefits from all of these activities, they are most unlikely to offer any protection to the VDU operator who spends eight hours a day in front of a VDU doing rapid, repetitive work with little or no control over the job, and the threat of the sack if they complain about the conditions.

'Stress management' implies that workers suffering from stress are unable to cope due to individual weakness or incompetence - thereby absolving employers from the responsibility to design the job to fit the workers, rather than insist the workers adapt to fit the system.

VDU workers should take up their rights under the new regulations to information (Regulation 7) and training (Regulation 6) on all aspects of health and safety relating to their workstations, and to a properly planned daily work routine which allows for sufficient breaks and changes of activity to:

It is worth noting that while the HSE has dismissed many of the health concerns of VDU workers as being unfounded, in its annex to the regulations it acknowledges that many of the stress-related symptoms described by VDU workers are caused by

The HSE goes on to advice that the risks of physical fatigue and stress can be minimised by

A 1989 World Health Organisation meeting goes some way further than the HSE in making recommendations on the factors which should be taking into account in designing VDU-based jobs, including the following:

task variation, including the provision of some non-VDU work some degree of task complexity, consistent with the skill potential of individual users, and providing some degree of responsibility and opportunity for exercising judgement coherent job content, entailing some intrinsic meaning in tasks performed skill development, ensuring that past skills do not become obsolete without the opportunity for learning new ones feedback on performance, ensuring that it does not create excessive or unrealistic expectations that may result in stress control, implying some possibility of influencing the structure and planning of work tasks and scheduling of breaks.

The WHO goes on to recommend that

VDU work should not prevent the opportunity for social contact support should be provided by supervisors planning should take account of likely breakdowns and faults the work pace should not be dependent on colleagues or the system (Journal of Occupational Health 1989).

Unfortunately, all official UK institutions have shied away from specifying limits on the length of time which can be spent doing VDU work in any one day (an important factor in VDU workers' stress-related ill-health), although several trade unions have successfully negotiated 'maximum hours' agreements for their members.

The UK's official view is in contrast with the Australian Government which, following an epidemic of RSI in VDU operators resulting in several thousand claims for compensation, now recommends a standard daily maximum of five hours of VDU work (VDT News November/December 1992).

Given the volume of evidence showing that reports of ill-health related to VDU work increase in direct proportion to the number of hours spent at the VDU, it seems that the UK would be well advised to consider following the Australian example, and set a maximum daily limit.

Cancer

The association between jobs in which workers are exposed to low frequency electromagnetic radiation and an increased risk of cancer has been established for some time. An excess (a higher than expected level compared to the general population) of leukaemia and brain, skin, eye, breast and throat cancer have been reported for electrical engineers, power workers, projectionists, telephone lineworkers and radio and communications workers.

It is these studies which have concerned VDU researchers since VDUs also emit low frequency electromagnetic radiation. (See Chapter 7 for more about screen technology).

In 1990, the US Environmental Protection Agency was on the point of classifying extremely low frequency (ELF) electromagnetic fields as 'probable human carcinogens'. The classification was overruled on the grounds that the mechanism by which they caused cancer could not be established. Whether or not ELF eventually receives official designation as a cancer-causing agent, recent studies already give cause for concern.

In particular, a three-year Australian study of risk factors for brain tumours produced a result which the researchers had not anticipated: that women who use cathode ray tube VDUs had nearly five times the expected rate of brain tumours (Ryan et al 1992). The researchers point out that the total number of people investigated was small - 170 with brain tumours and 417 controls - but given the tens of millions of VDU workers around the world, even if there is even a small increased risk of brain cancer, this will affect very large numbers of people worldwide.

Ion effects and electrostatic fields

Although many claims have been made about the effects of ions (electrically charged particles) on health, little 'scientifically acceptable' research has been carried out. Some reports suggest that a lack of negative ions in the atmosphere is associated with depression, lethargy and anxiety and may increase the risk of diseases such as asthma, migraines and problems with blood clotting. In contrast, an excess of negative ions is reported to increase alertness, appetite, sounder sleep and fewer respiratory complaints. The mechanism for these effects is not known, although the limited research which has been done suggests that ions affect the hormonal system.

It is known that electrostatic fields from operating VDUs do deplete the concentration of ions, so as well as reducing the risk of skin rashes, and shocks from the discharge of built-up static electricity, reducing the electrostatic fields from VDUs may improve the air ion concentration. Ducted air conditioning, smoke and contamination and a high density of individuals in the workplace can also contribute to low air ion levels (London Hazards Centre 1990).

Ways of reducing static electricity include making sure that VDUs and other equipment are properly earthed, controlling humidity and temperature, removing pollutants and dust at source and ensuring that offices are not overcrowded.

Electrical hypersensitivity

In Sweden, work has been going on during the last few years to investigate cases of a condition known as electrical hypersensitivity (PROSA 1992). The condition may appear first in the form of skin problems but may progress to include dizziness, fatigue, headache, impairment of memory, breathing difficulties and eyesight problems. Most sufferers' symptoms will disappear when they go away from the VDU, but some develop a general hypersensitivity to sources of electricity which causes the symptoms to persist even when they are at home.

Very low frequency magnetic fields (such as those emitted from VDUs) are the probable cause electrical hypersensitivity and possibly increase the risk of mercury poisoning by accelerating the release of mercury from mercury amalgam fillings. In Sweden and in the USA it is believed that many cases of chronic fatigue syndrome seen in VDU workers may be due to mercury poisoning.

Ozone from printers

Ozone is a sweet-smelling, highly toxic gas produced during the high voltage electrical discharge in photocopiers and laser printers (Daily Hazard August 1990). Health effects of ozone exposure include eye, nose, throat and lung irritation, dermatitis, headaches and nausea, premature ageing and potential reproductive dangers. The UK occupational exposure limit (OEL) for ozone is 0.1ppm. But if you can smell ozone, the concentration is too high. Most laser printers have ozone filters but these should be regularly checked and replaced - as often as once a month for printers in very heavy use. Effective ventilation of the area in which the printer is sited is essential. Laser printers should be properly installed and regularly maintained and serviced.

In the previous chapters we have looked at the range of health effects attributed to VDU work. In the following chapters, we examine the equipment itself, the law on VDU work and workplace ergonomics.