Shiftworking and employee health: squaring the circle

Shiftworking poses a threat to employees' health, with potential knock-on effects on absence, staff retention and costly accidents at work. We analyse what can be done to minimise these problems.

Learning points Shiftworking can have a significant impact on employees' health, raising the possibility of employer liability, higher resignation rates and work-related accidents and mistakes. Employers have particular duties under the Working Time Regulations 1998 to carry out risk assessments for nightworkers, and to offer such employees a regular free health assessment, alongside their general duty to undertake risk assessments for all staff. Our research indicates that most employers are aware of their responsibilities to shiftworkers under health and safety law. Most employers contacted by us consider that absence rates and accidents are not higher among shiftworkers, although a minority has found the opposite to be true.

Health considerations are unlikely to feature strongly in an employee's decision whether or not to choose to undertake shift work. But the health impact of working at night or other unsocial hours - the most frequently reported disadvantage of shiftworking - can push up resignation rates and open the door to higher levels of accidents and mistakes at work.

In the NHS, where shiftworking is common, poorly structured shift patterns are encouraging some workers to become dependent on caffeine to keep them awake and pills to get them to sleep, according to members of the Unison trade union.

The union's health conference last year called for urgent action to tackle the stresses of working alternate day and night shifts, arguing that this particular shift pattern damages workers' physical and mental health and disrupts family life. Unison is calling for shift patterns to be thoroughly risk assessed and carefully planned and implemented to minimise the potential health risks.

Circadian rhythms

The move away from an economy based on manufacturing towards service sector work has done nothing to reduce the prevalence of shiftworking. Indeed, the growth of 24-hour shopping, 24/7 call centres and other aspects of modern life have given it a boost.

There is, therefore, an increasing onus on employers to take account of the potential impact of shiftworking on workers' health and safety.

The effect on health of shift- and nightworking has been studied for many years, and there is clear evidence that these work patterns unbalance both a worker's circadian, or biological, and social rhythms.

Circadian rhythms include sleep patterns, body temperature, alertness and metabolism - in other words, the body's internal clock.

Shift work can also disturb a person's social balance, which is based on the shared experiences of family meals, recreation, work and sleep. Adopting patterns in all these areas that are out of synchronisation with those of family and friends can distance shiftworkers from everyday social and family life.

A wide range of health problems is linked to shift work, including digestive complaints, particularly among nightworkers. Night shiftworkers are five times more likely to develop ulcers and other stomach problems than day workers, or other shiftworkers not on nights, due partly to unsuitable food being taken in unsuitable quantities and at unsuitable times.

Shiftworkers have higher rates of anxiety and depression - switching from day to night work is physically and emotionally draining and some people find it hard to sustain relationships in these circumstances. Shiftworking is also linked to a rise in heart disease risk factors, altered bowel habits, asthma, epilepsy and chronic fatigue syndrome.

Sleep debt

Sleep disturbances are common among shiftworkers owing to a combination of sleep loss and the need to be alert and awake when the body's natural rhythms suggest sleep. The cumulative sleep loss resulting from night shiftworking can lead to sleep debt and long-term fatigue.

Sleep debt is worsened by workplace environment factors, including poor lighting, high temperatures and noise levels, according to a report on shiftworkers' health by the London Chamber of Commerce and Industry¹.

The excessive fatigue and sleepiness associated with cumulative sleep debt can have a major impact on performance and safety standards. Fatigue may develop only slowly, in a way that is not always apparent to workers themselves or their managers.

However, the lapses in concentration that often result from fatigue can lead to severe accidents. The Health and Safety Executive (HSE) believes that fatigue from shiftworking and overtime is one of the most frequent factors behind major accidents. Driving home at the end of a night or late shift is a particularly dangerous pursuit, as it often takes place when the need for sleep is at its strongest.

Which shifts are worse?

A recent research report for the HSE² examined the various shift patterns of offshore oil workers to see which pattern of two-week offshore work involves the least disruption to circadian rhythms.

Oil workers doing 14 nights or 14 days experienced the least disruption and, therefore, found it easier to adapt to "normal" life after a stint offshore. Working during the day for seven days, followed by seven nights of work, was also found to upset internal body clocks to a relatively small degree, even though this pattern left workers returning home synchronised with nightworking (it is easier to adapt at home, the researchers conclude).

The worst shift pattern for biological rhythms is seven nights followed by seven days. Workers find it particularly difficult to adapt to day shifts after a period on nights because daylight is present over the full duration of the shift, countering adaptation.

Somewhat inconveniently, the researchers conclude that a schedule involving a shift changeover at 3am would cause the least disruption to circadian rhythms, as very little circadian adjustment would be required. Two shift patterns would be ideal for worker adaptation purposes - an early one between 3am and 3pm and a late one between 3pm and 3am - the researchers conclude.

The effects of light are crucial to how workers adapt to different shifts, and the HSE report recommends a range of interventions to help this process, including timed light treatment to encourage faster adaptation to new shift patterns. For example, workers on a 14-night pattern could be advised to avoid light immediately after the shift ends, especially on the first few night shifts, in order to prevent counteractive light effects.

Sleep strategies can also help with adaptation. Employers and workplace health advisers should recommend that people coincide sleep with the period when they should be avoiding light (that is, immediately after a shift in the case of nightworkers).

Naps during night shifts, especially on the first night, may be a useful strategy to improve immediate alertness, but need careful timing, the HSE report suggests. The value of "power naps" for nightworkers has also recently been supported by two psychiatrists in a guide for doctors³ on surviving night shifts, which includes taking short naps.

The HSE report also recommends that shiftworkers avoid fatty foods and snacks at night, particularly at the start of a night shift.

The London Chamber of Commerce guide stresses the importance of workplace environment factors in mitigating the health impact of shiftworking, suggesting that employers should provide their shiftworkers with healthy food choices and the means of preparing meals.

Ventilation should also be checked in areas where night shiftworking is prevalent, and bright lighting provided in order to signal to the body that it is time to be awake and alert. If this is not possible because of the nature of the work, employers should attempt to provide bright lighting in some areas where possible, for example, at a record station in the case of a hospital ward that cannot be brightly lit at all times.

Women's health

The number of women working night shifts has grown in recent years, particularly with the arrival of call centres, and research suggests that shiftworking might have particular health impacts for women, including on their menstrual cycles and in increasing the risk of certain diseases.

Some of the research to date is inconclusive, but some does suggest there are health concerns, such as a higher incidence of miscarriage, and premature and low birth-weight babies as a result of irregular working hours. A meta-analysis - an in-depth scrutiny of research findings - published last year⁴ looked at 13 studies and concluded that these showed a significantly raised risk of breast cancer among female airline cabin crew, and female nightworkers generally.

Working Time Regulations

The Working Time Regulations came into force on 1 October 1998 and impose obligations on employers, including nightwork restrictions and health assessments for nightworkers.

Regulation 6 contains measures relating to nightworking, and states that the normal working hours of nightworkers must not exceed an average of eight hours in a 24-hour period, calculated over a 17-week reference period.

This measure is modifiable by agreement between employers and workers, except in the case where the work involves special hazards, or heavy physical or mental strain, where no nightworker may work for more than the specified hours.

However, these night restrictions do not apply to those working in the security and surveillance industries, or in situations where there is a need for continuity of service or production, for example, healthcare and airports, or where there is a foreseeable surge in work activity.

Employers are required to carry out risk assessments for nightworkers, which should be used to assess whether groups of workers fall into the job categories not eligible for the night work restriction opt-out (that is, to identify those that involve special hazards or heavy strain).

Risk assessments should identify any "special hazards" facing nightworkers, prioritise them according to their significance, and reduce the risks as much as reasonably practicable. In conducting assessments, employers need to look at whether the work becomes particularly hazardous when carried out at night. This might be the case, for example, if tasks become more difficult when performed in darkness, or because the full range of daytime services may not be available at night, or when those performing them find it difficult to adjust to the shift patterns required.

Health assessments for nightworkers

Regulation 7 of the Working Time Regulations 1998 requires employers to offer a free health assessment to any worker who is to become a nightworker, unless a previous assessment is still valid. Nightworkers must also be offered further assessments at regular intervals.

No standard for the quality or content of these health assessments is set out by the regulator, but, as a minimum, the HSE recommends that employers should construct a screening questionnaire compiled with guidance from a qualified health professional. Acas recommends that assessments should be repeated annually.

Special provisions on health assessments apply to young workers aged under 18 employed at any time between 10pm and 6am.

The requirement to offer nightworkers a health assessment complements other duties on the employer under the Management of Health and Safety at Work etc Regulations to make a suitable and sufficient assessment of the risks to employees' health and safety. Employers also have a duty to redeploy those doing nightwork to a more suitable working pattern if a registered medical practitioner advises that the worker is suffering health problems connected with nightwork.

Employers control shiftworking

IRS Employment Review has conducted research into employers' shiftworking practices (see Shiftworking ticks along nicely and Paying a premium for shift work  for our findings on shift patterns and shift payments). In all, 71 employers gave us feedback about their practices, of which a large majority (89%) impose some limits or special provisions on shiftworking and shiftworkers for health and safety reasons.

The most frequently used controls relate to the provision of rest breaks during shifts and minimum breaks between shifts (see table 1). Other frequently used controls cover the actual length of each shift, the number of shift days worked in a row, and restrictions on double shiftworking.

Several organisations told us that the Working Time Regulations are taken into account when selecting shift patterns. For example, one private sector employer does not employ under-18s on night shifts, while a second states that compliance with the Regulations is an important consideration generally in determining working patterns.

Impact on absence

There is little evidence from our research that shiftworkers have higher sickness absence or accident rates than employees as a whole.

For example, two-thirds (64%) of the employers we contacted told us that there is no difference between the short-term sickness absence rates of shiftworkers and their employees not on shifts.

Similarly, two-thirds (64%) said that there is no difference between shiftworkers and non-shiftworkers in respect of long-term absence rates. A higher proportion - approaching three-quarters (7 1%) - told us that there is nothing to choose between the number of employees referred to occupational health specialists on the basis of whether or not they work shifts. And much the same proportion (72%) said that the number of accidents at work shows no real difference between shiftworkers and non-shiftworkers.

However, when we turn to the minority of employers that did notice a difference in absence and accident rates between their shiftworkers and other employees, we find a noticeable pattern emerges. Almost all of this group says that absences, occupational health referrals and accidents are relatively higher among shiftworkers than those on standard day work.

¹24/7 health effects: shift and night working, an employer's guide, London Chamber of Commerce and Industry, 2004,www.londonchamber.co.uk.

²Effect of shift schedule on offshore shiftworkers' circadian rhythms and health, HSE research report no.31 8, 2005,www.hse.gov.uk.

³"Working the night shift: preparation, survival and recovery — a guide for junior doctors", Royal College of Physicians, 2006, www.rcplondon.ac.uk.

⁴"Night work and breast cancer risk: a systematic review and meta-analysis", Megdal, SP et al, European Journal of Cancer, vol. 41, issue 13, September 2005, pp.2,023-2,032.

See Shiftworking ticks along nicely and Paying a premium for shift work for our research findings on shiftworking patterns and shift pay.

Checklist: Reducing the impact of shiftworking on health Shiftworking can have a significant impact on employees' physical and mental health, raising issues of employer liability, higher resignation rates, and accidents and mistakes at work. Research shows that there are ways of minimising the detrimental impact of working shifts. These can be considered as part of an employer's legal duties to assess the risks of shiftworking. A six- to 12-month trial period for new shiftworking systems should be allowed. Rotating shifts may work for employees who do not want to work permanent nights. Fixed shifts may help employees schedule childcare and other family commitments. The impact of nightworking can be reduced through adequate lighting levels, good temperature, ventilation and noise controls, facilitating 'power naps' and by the shift patterns used. Advice can be given to workers about adjusting their sleep patterns, eating habits and exposure to light. Poor diet contributes to the health impact of shiftworking; employers should provide adequate kitchen facilities and healthy food choices where there is on-site catering. A short-cycle schedule, under which the number of consecutive night shifts is small, presents fewer health risks and has a positive impact on the leisure time of workers. Jobs within a team of shiftworkers could be rotated where particular jobs require high levels of concentration. Shift rosters should be set well in advance to allow employees to plan their leisure time. Sufficient time between shifts should be allowed for travel, washing, eating and sleeping, and for employees to attend to their personal lives. Employees should be allowed to change shifts where practicable. Some employers have found that self-rostering can operate satisfactorily, enabling workers to balance their personal and work lives and reducing stress through greater job control. Table 1 shows the most common ways that employers manage shiftworking to minimise its health risks. Sources: "24/7 health effects: shift and nightworking, an employer's guide", London Chamber of Commerce and Industry, 2004; "Effect of shift schedule on offshore shiftworkers' circadian rhythms and health", HSE, 2005; and IRS.

Table 1: Shiftworking and health considerations

Our research shows that most employers are making at least some adjustments to the working practices and patterns of shiftworkers with their health and safety in mind.

Adjustment/Limitation	% of employers
Rest breaks during shifts	73
Minimum break between shifts	69
Length of shifts	55
Number of consecutive shift days	48
Restrictions on double shiftworking	39
Limits on night shifts	21
Other	13

n = 62.

Source: IRS.