Night work

A night worker is defined as someone who works at least three hours of their daily working time during the night time “as a normal course” (Regulation 6).

Night time is a period of at least seven hours, including the period between midnight and 5am, as laid down in an agreement or contract or, in the absence of such an agreement, the period between 11pm and 6am (Regulation 6). A night worker must not normally work more than eight hours in each 24-hour period when averaged over any period of 17 weeks (the reference period).

If the length of night work is altered or excluded by a collective or workforce agreement, compensatory rest must be made available. Mobile workers are excluded from the night work limits. Instead, they are entitled to “adequate rest”.

The Working Time (Amendment) Regulations 2002 changed the definition of night working hours to include all overtime (rather than just guaranteed overtime) in the calculation of average night working limits.

Some sectors (including hospitals, agriculture, retail trading, hotels and catering businesses, bakeries, fisheries and postal and newspaper deliveries) are exempted from the night working restrictions because of their particular operational needs. Work in bars and restaurants are also exempted.

Night work and young workers

Young workers may not ordinarily work at night between 10pm and 6am (or between 11pm and 7am where the contract of employment allows for work after 10pm).

Health assessments

Employers must ensure that night workers whose work involves special hazards or heavy physical or mental strain do not work more than eight hours in any 24-hour period. This includes work that a risk assessment carried out under the Management Regulations (see Chapter 2) shows to involve a significant risk.

Employers must not assign adult workers to night work unless the worker has been offered a free health assessment. These should be available at appropriate regular intervals and can be provided by an occupational health doctor or GP. If a doctor advises an employer that a worker’s health problems are likely to be connected with night work, and it is possible to transfer them to suitable work that is not night work, the employer must transfer the worker to daytime work (Regulation 7(6)).

However, there is no absolute protection for workers, other than pregnant women and disabled people, if there is no suitable work to transfer to. This means an employer may be able to dismiss a worker fairly in these circumstances.

Research linking shift work and health problems

A report published by the Health and Safety Executive (HSE) in 2010 estimated that more than 550 UK breast cancer deaths and almost 2,000 cases of breast cancer are linked to shift work. This represents almost half of all occupationally-related cancer registrations (1,971 out of a total of 3,622) in women. The Burden of occupational cancer in Great Britain, Imperial College London, the Institute of Environment and Health and the Health and Safety Laboratory (HSL), provides an updated estimate of the number of cancer cases and cancer deaths caused by work. It can be found at: www.hse.gov.uk/research/rrhtm/rr800.htm

More recently, a Canadian study reported that working night shifts for more than 30 years could double the risk of developing breast cancer. Researchers examined 1,134 women with breast cancer and 1,179 women of the same age without the disease. They questioned them about their work and shift patterns and assessed hospital records. An association was not found for those doing night shifts for less than 30 years. The results of the study were reported in TUC Risks e-bulletin: www.tuc.org.uk/workplace/tuc-21700-f0.cfm#tuc-21700-10

In January 2014, researchers at the Sleep Centre at Surrey University made a disturbing finding on the implications for those working on night shifts. They found that a change to regular sleeping times affects people at a genetic level, influencing the daily rhythm of our genes.

The study was carried out on 22 participants who had their sleep deliberately disrupted to show the effect of working night shifts on the human body. This research has been published in the Proceedings of the National Academy of Sciences.

Research reported in July 2014 found that shift work carries a 9% higher risk of type 2 diabetes compared with normal office hours. The authors of the study, published in the Occupational and Environmental Medicine journal said that the risk appeared to be highest among men and those who work rotating shift patterns. Men who worked shifts were 37% more likely to develop diabetes and those who worked rotating shift patterns had a 42% higher risk than those who worked a fixed shift pattern. The study was carried out by researchers at Huazhong University of Science and Technology in China. More information can be found online at: http://oem.bmj.com/content/early/2014/06/12/oemed-2014-102150.abstract

And new research published in the Occupational and Environmental Medicine journal in November 2014 found that working shifts “chronically impairs cognition”, significantly damaging the ability to think and remember. Doing so for at least ten years “ages” the brain by an extra six and a half years, researchers at Swansea and Toulouse universities found. The findings add to those linking shift work with cancer, heart disease, diabetes and other health effects.