15% of the U.S. full-time workforce works shifts outside the typical 9-5 day schedule. These workers are at increased risk of fatigue and shift-work disorder. (sleepfoundation.org)
Further, a large portion of these workers work in safety-sensitive industries such as transportation, construction, healthcare, utilities, mining, aviation, agriculture, manufacturing, etc. Fatigue and shift-work disorder, if left unmanaged, could pose serious safety threats and reduce the productivity and performance of these workers.
What is Shift-Work Disorder?
Shift-work disorder is a chronic sleep disorder caused by the disruption of normal sleep patterns and the worker's natural circadian rhythm. It often results in problems with falling asleep and staying asleep at home, or staying awake and alert at work.
The following are common symptoms of shift-work disorder, according to the Sleep Foundation:
- Excessive sleepiness at work
- Inability to sleep when needed, such as difficulty falling asleep, difficulty staying asleep, or difficulty waking up
- Unrefreshing or insufficient sleep
- Difficulty focusing or staying alert
- Lack of energy
- Problems with personal relationships
How Does Circadian Disruption Affect the health of Night Shift Workers?
Circadian disruption and the ensuing fatigue caused by night-shift work can lead to the following health outcomes for workers:
- Short-term cognitive effects: Impaired memory, concentration, vigilance, reaction-time
- Short-term health issues: Increased stress, depression and reduced immune strength
- Short-term business outcomes: Increased absenteeism, presenteeism, burnout, higher incident frequency, increased errors
- Long-term health issues: Digestion problems, heart disease, increased risk of cancer, obesity, and more
- Long-term business outcomes: Increased turnover, reduced productivity, increased insurance rates, increased safety costs
(Infographic from healthline.com)
How Does Circadian Disruption Affect the Performance of Night Shift Workers?
The symptoms of shift-work disorder, especially difficulty staying alert and excessive sleepiness, have profound negative impacts on safety and productivity at work. Sleep-deprived workers tend to make more errors, take more sick leave, become moody, and they often suffer temporary or permanent health problems (Bates). The following are findings from research studies that demonstrate the impact of shift-work and circadian disruption on work accidents, errors, and productivity.
Workplace accidents caused by night shift work and circadian disruption:
- Work accidents predominantly occur during night shifts. (Ackerstedt, Wright, 2009)
- Single vehicle truck accidents occur most often during night shift. (NTSB)
- 30-40% of all US truck accidents are fatigue-related. (NTSB)
- In car manufacturing, there was a 30-50% increase in accident risk during the night shift. (Smith, Folkard, Poole)
- Fatal occupational accidents were higher in night shift workers. (Akerstedt, et al)
Workplace errors caused by night shift work and circadian disruption:
- Errors in meter readings at a gasworks peaked on the night shift, in a study spanning 20 years. (Bjerner, Holm, Swensson)
- The Chernobyl nuclear disaster was due to human error related to night shift and work scheduling. (Mitler, et al).
- Nurses on rotating night shifts were twice as likely to have a reported accident or error. (Gold, et al)
- Reducing interns' extended work shifts decreased attentional failures during night shifts. (Mitler, et al)
- Sleep deprivation due to night shift work caused significant declines in worker productivity. (Vidacek, et al)
- Telephone operators connected calls significantly more slowly during night shifts. (Browne)
- The speed of spinning threads in a textile mill went down during night shifts. (Wojtczak-Jaroszowa)
What can workers Do To Reduce Risk of Fatigue and Shift-Work Disorder?
The negative impacts of shift-work and circadian disruption on workplace accidents, reduced productivity, and increased errors are well-known. However, shift work and night shifts remain an essential part of our society and economy.
So, what can workers do to minimize the effects of shift work on their personal health and wellbeing?
Here are some tips to share with your night shift workers:
1. Avoid swapping shifts or changing your schedule too often.
2. Get adequate sleep before going into work, and take a nap during night shifts if permitted.
3. As permitted, to stay awake at work, turn on bright lights, listen to music, converse with workers, and avoid tedious tasks around 4 am, when most night shift workers are least alert.
4. Use heavy curtains, an eye-mask, and earbuds to reduce light and noise while sleeping.
5. Avoid consuming too much sugar during night shifts so you don't crash before the shift is over.
6. Disconnect phones, doorbells, etc. to avoid disruption of sleep.
7. Do not drink alcohol or smoke before bed as they will interfere with getting quality sleep.
8. Avoid watching TV or looking at your phone before going to sleep.
9. Avoid light exposure while returning from a night shift by wearing sunglasses.
10. Do not drink caffeine or exercise towards the end of a night shift as they can delay sleep when you get home.
11. Maintain the same schedule on days off and give yourself a few days to adjust to a new sleep schedule before going into work.
What Can Employers Do To Reduce Fatigue Risk on Night Shifts?
Businesses rely on the safe and productive performance of night shift workers. Although many employers are familiar with the risks fatigued night shift workers bring to the workplace, they find it difficult to manage these risks without overstepping professional boundaries or invading workers' privacy.
Here are some tips to reduce fatigue risk and circadian disruption in workers without being invasive or punitive:
12. Schedule workers strategically to reduce fatigue risk and introduce countermeasures during fatigue hotspots. Click here to get a fatigue risk shift schedule assessment.
13. Keep worker schedules consistent and predictable so workers don't have to constantly readjust their sleep patterns.
14. Avoid scheduling overtime or double shifts.
15. Limit consecutive night shifts.
16. Allow frequent breaks for night shift workers to nap, hydrate, snack, or exercise to promote alertness.
17. Designate areas and times for night shift workers to nap.
18. Use music or ambient noise to ward off fatigue during night shifts.
19. Install bright lights to keep night shift workers alert.
20. Educate night shift workers on fatigue countermeasures, found here.
21. Frequently screen night shift workers for sleep apnea and other sleep-related disorders.
22. Encourage night shift workers to get regular physical exams to identify and manage health effects of circadian disruption.
Akerstedt T, Fredlund P, Gillberg M, Jansson B. A prospective study of fatal occupational accidents -- relationship to sleeping difficulties and occupational factors. J Sleep Res. 2002 Mar;11(1):69-71. doi: 10.1046/j.1365-2869.2002.00287.x. PMID: 11869429.
Akerstedt, T., & Wright, K. P., Jr (2009). Sleep Loss and Fatigue in Shift Work and Shift Work Disorder. Sleep medicine clinics, 4(2), 257–271. https://doi.org/10.1016/j.jsmc.2009.03.001
Bates, S. (2019, August 16). How HR Can Help Sleepy Shift Workers. SHRM. https://www.shrm.org/hr-today/news/hr-magazine/1116/pages/how-hr-can-help-sleepy-shift-workers.aspx.
Browne, R. C. (1949). The day and night performance of teleprinter switchboard operators. Occupational Psychology, 23, 121–126.
Gold, D. R., Rogacz, S., Bock, N., Tosteson, T. D., Baum, T. M., Speizer, F. E., & Czeisler, C. A. (1992). Rotating shift work, sleep, and accidents related to sleepiness in hospital nurses. American journal of public health, 82(7), 1011–1014. https://doi.org/10.2105/ajph.82.7.1011
Government of Canada, C. C. for O. H. and S. Rotational Shiftwork : OSH Answers. Canadian Centre for Occupational Health and Safety. https://www.ccohs.ca/oshanswers/ergonomics/shiftwrk.html.
Mitler, M. M., Carskadon, M. A., Czeisler, C. A., Dement, W. C., Dinges, D. F., & Graeber, R. C. (1988). Catastrophes, sleep, and public policy: consensus report. Sleep, 11(1), 100–109. https://doi.org/10.1093/sleep/11.1.100
Nichols, H. (n.d.). Five ways to deal with night shifts. Medical News Today. https://www.medicalnewstoday.com/articles/319918#3.-Watch-your-diet.
National Transportation Safety Board. 1995. Factors that affect fatigue in heavy truck accidents. Volume 2: Case summaries. Safety Study NTSB/SS/95/02. Washington, DC. https://www.ntsb.gov/safety/safety-studies/Documents/SS9502.pdf
Shift Work Disorder: Symptoms & Risks: Sleep Foundations. Sleep Foundation. (2020, October 16). https://www.sleepfoundation.org/shift-work-disorder/symptoms.
Smith L, Folkard S, Poole CJ. Increased injuries on night shift. Lancet. 1994 Oct 22;344(8930):1137-9. doi: 10.1016/s0140-6736(94)90636-x. PMID: 7934499.
Vidacek, et. al. (1986) Productivity on a weekly rotating shift system: circadian adjustment and sleep deprivation effects? Ergonomics, 29:12, 1583-1590, DOI: 10.1080/00140138608967271
What are cognitive abilities and skills, and can we boost them? SharpBrains. (2020, August 21). https://sharpbrains.com/what-are-cognitive-abilities/.
Wojtczak-Jaroszowa, J., & Jarosz, D. (1987). Chronohygienic and chronosocial aspects of industrial accidents. Progress in clinical and biological research, 227B, 415–426.