Night and shift work



Many research studies have found that working at night is linked to increased risks of cardiovascular disease, diabetes and depression. It can also have an impact on home life and relationships and a 2013 Danish survey suggested a possible link between night shifts and a raised risk of miscarriage. NHS advice is that since the evidence of a raised risk of miscarriage is comparatively weak and limited, they do not recommend a mandatory change to shift patterns. Instead, any change to working patterns should depend on the needs of the individual woman.
Night work can also disrupt successful breastfeeding.



A 2017 Oxford University study concluding that “night shift work, including long-term shift work, has little or no effect on breast cancer incidence” was dismissed as “bad science” by the safety campaign journal, Hazards. After consulting a number of expert epidemiologists, it said that the cancer all-clear was flawed and pointed out that the International Agency for Research on Cancer, part of the World Health Organisation, has ranked night work as a “probable” cause of breast cancer in women.


In January 2018, the European Trade Union Institute (ETUI) highlighted the findings of new studies confirming the conclusions of earlier research highlighting an increased risk of cancer for workers who carry out night or shift work. 


Researchers at Sichuan University in China reviewed 61 studies on the effects of night work on the health of women between 1996 and 2017. The data cover 115,000 cases of cancer and four million participants living in the US, Australia, Asia and Europe. The study concluded that the long-term risk of breast cancer increases by 32%, that of skin cancer by 41%, and that of gastrointestinal cancers by 18%. The risk of breast cancer increases by 3.3% for every five years of night work. Nurses are the worst affected occupation.


Meanwhile, a study published in the Scandinavian Journal of Work Environment and Health found that male workers carrying out shift or night work have a higher risk of contracting prostate cancer. The risk is double that for workers who have never worked shifts, while men who have worked shifts or nights for more than 20 years are three or four times more likely to get prostate cancer. 


A recent TUC analysis found the number of people regularly working nights has shot up by 260,000 over the past five years — a 9% increase. Around 3.2 million workers (one in nine or 12% of the workforce) now work nights. That figure increase to one in six (18%) black workers — significantly more than the one in nine (11%) white workers who do so. Over 150,000 black workers now do night work. The majority (62%) of night-workers are male, but women now make up well over a third (38%). One in 11 women work nights, compared to one in seven men. Previous TUC research found night working is most common in occupations and industries such as security, logistics, manufacturing and healthcare. 


The TUC has warned that preventative advice is not keeping pace with the evidence of harm and HSE advice on managing shift work is now more than a decade old and pre-dates much of the new evidence on chronic risks.



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 is also exempted.



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).