Shiftwork - health effects

There is increasing evidence becoming available that shift work can lead to very serious consequences.

Shift work can be described as any shift outside the normal daylight hours of 7am to 6pm.

Increasing research is linking  shift work to poorer sleep, circadian rhythm disturbances, and strains on family and social life. Night work and shift work have been linked to serious conditions from cancer to heart disease. Fatigue can be deadly. In our society it is not possible to eliminate shift work, and so it is necessary to develop strategies to make critical services available while keeping workers healthy and everyone around them safe.

In addition to more workers working shift work, there are growing numbers of workers working long hours on a regular basis - or others having to juggle more than one job over several parts of the day. Every extra hour on the job is one less spent someone's off-the-job responsibilities (eg with family). When the day is too full to fit everything in, it is often sleep that gets the short shrift.

The hours we work and the hours we sleep are a crucial health and safety issue.

Page Overview

• Shift Work Disorder (SWD)
• 2015 Health Study
• NIOSH Work and Sleep Blog
• Canadian Institute for Work and Heath
• UK Trade Union Congress
• Shift Work and Heart Problems
• References

Shift work disorder (SWD)

Shift work disorder (SWD), which is characterized by insomnia and excessive sleepiness related with shift work, is one of the most common health problems in shift workers.

Shift work disorder causes insomnia, fatigue, worse work performance, an increased likelihood of workplace incidents ('accidents'), and a poor quality of life. In addition, SWD is associated with decreased productivity and increased economic costs. The correct management of SWD is important to prevent sleep disturbances and maintain work performance in shift workers.

To diagnose and evaluate SWD, it is necessary to take detailed medical histories, assess the severity of sleep disturbances, and evaluate shift workers' sleep using a sleep diary and actigraphy (a non-invasive method of monitoring human rest/activity cycles). The work-fitness evaluation should include recommendations on how shift workers can reduce their sleep disturbances and increase work performance, as well as the assessment of work performance. A recent research paper reviews previous research on the evaluation, diagnosis, and management of SWD and summarizes the work-fitness evaluation of SWD. Read more: Tae-Won Jang: Work-Fitness Evaluation for Shift Work Disorder [Open access] Int. J. Environ. Res. Public Health 2021, 18(3), 1294; https://doi.org/10.3390/ijerph18031294

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2015 Health Survey for England survey conducted by the Health and Social Care Information Centre

The results of this survey are as follows:

• • Shift workers have higher rates of obesity and ill-health than the general population.
    The data from the survey showed that 30% of shift workers were obese, compared with 24% of men and 23% of women working normal hours.
  • 40% of men and 45% of women on shifts had long-standing health conditions, such as back-pain, diabetes or chronic obstructive pulmonary disease, compared with 36% and 39% of the rest of the population.
  • 'Night owls' are also more likely to smoke, which could exacerbate many of the illnesses they are at risk of developing.
  • Shift work is most common in the 16-24 age group; an age group that should exhibit better levels of health and cognitive performance.
    The rates fell with age so that fewer than a third of men and a fifth of women were working shifts after the age of 55.

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US National Institute for Occupational Safety and Health (NIOSH) Work and Sleep Blog

What are the risks of long work hours and shift work?

Risks for Workers:

• Sleep deprivation   
• Lack of adequate time to recover from work
• Decline in mental function and physical ability, including emotional fatigue and a decline in the function of the body's immune system 
• Higher rates of depression, occupational injury, and poor perceived health
• Higher prevalence of insomnia among shift workers with low social support
• Increased risk of illness and injury
• Strain on personal relationships, such as marriage and family life
• Increased risk of long-term health effects, such as heart disease, gastrointestinal disorders, mood disturbances, and cancer

Risks for Employers:

• Reduced productivity
• Increase in errors
• Absenteeism and presenteeism (present at work but not fully functioning because of health problems or personal issues) 
• Increased health care and worker compensation costs
• Workforce attrition due to disability, death, or moving to jobs with less demanding schedules

Risks to the Community:

• Medical errors
• Vehicle crashes
• Industrial disasters

• Sleep and Work blog 
• NIOSH Research on Work Schedules and Work-related Sleep Loss

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Canadian Institute for Work and Health

September, 2010

The Canadian Institute for Work and Health, an independent not-for-profit organisation whose mission is to conduct and share OHS research, has published an issues briefing on the impact of shift work on health. The research has noted some concerns involved with shift work.

The key messages from the research are:

• • People who work night shifts are likely to have shorter sleep duration and/or poorer sleep quality than regular day workers.
  • Long-term exposure to night shift work may elevate the risk of breast cancer. There are also findings pointing to an elevated risk of colorectal cancer.
  • Some studies indicate an elevated risk of preterm delivery, gastrointestinal disorders and mental health problems among shiftworkers.
  • Research findings regarding a causal link between shiftwork and heart disease are inconsistent.
  • Shiftworkers, especially those working at night, face a higher risk of workplace injury than regular day workers.
  • Promising approaches to mitigate the adverse effects of shiftwork include restricting successive evening or night.
  • Shifts to three shifts, limiting weekend work, moving from backward to forward shift rotation and using a participatory approach to the design of shift schedules.
  • More research is needed to resolve some of the questions regarding the health effects of shift work, and to investigate the impact of interventions designed to mitigate the adverse consequences of shiftwork on health.

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UK Trade Union Congress