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How Does Shift Work Affect Circadian Rhythm? How Can Sleep Hygiene Help?

Our bodies have an intrinsic timekeeping system that regulates sleep, wakefulness and other systems such as temperature, appetite and hormone levels. This built-in system is called the circadian rhythm. 

For most people the circadian rhythm drives wakefulness during the daytime and promotes sleep at nighttime. This is because the biggest environmental contributor to sleep-wake cycles is light vs dark. Light, especially bright light, promotes alertness. Darkness leads to release of melatonin, a hormone that is released from the pineal gland in response to darkness, which promotes sleep. This makes sleeping much easier and more natural at night. 

However, shift workers do not always have the luxury of sleeping at night due to their hours of work. I am fortunate to no longer work night shifts, but my husband continues to have to work overnights some evenings when he is on call.

Establishing healthy sleep hygiene is even more important to maintain good health for those individuals whose schedules force them to sleep during the day and work during the night.

Sleep Disorders in Shift Workers

Circadian rhythm sleep disorder (CRSD) is a DSM-5 class of sleep disorders in which there is a persistent and recurrent pattern of disruption to one’s internal sleep clock (American Psychiatric Association, 2013). Sleep disorders can manifest as excessive sleepiness and/or insomnia. This can lead to fatigue, distress and can impair social or occupation functioning. 

There are multiple subtypes of circadian rhythm sleep disorders including shift work type insomnia. This is defined as insomnia secondary to shift work and/or fatigue which can include falling asleep unintentionally during unconventional work hours. Shift workers often describe difficulty falling asleep, broken sleep, poor sleep quality, and reduced duration of sleep.  This is because they are trying to sleep when the body is promoting wakefulness.  It is estimated that 5-10% of night shift workers experience CRSD.

Insufficient sleep can cause a wide range of health issues including metabolic syndrome, gastrointestinal problems, cancer, depression, heart disease, excessive sleepiness and accidents. 

Sleep Hygiene Strategies for Shift Workers

The best way for shift workers to manage their sleep is to ensure they follow the usual recommended sleep hygiene strategies for everyone with a few modifications. These include:

  • Try to get an appropriate amount of sleep and have a regular sleep schedule.
  • Caffeine consumption can be helpful early in a shift but should be stopped at least 4 hours before going to bed. 
  • Maximizing light exposure during wakefulness and minimizing light exposure immediately prior to and during sleep. 
  • Black out blinds can be utilized to improve quality of sleep when it is still bright out. Your room should be dark, quiet and cool.
  • Bright light therapy lights can be used for the purpose of increasing wakefulness when the sun is not out. 
  • Utilizing naps as needed and permitted.
  • Healthy and regular eating and staying well hydrated.
  • Regular exercise.
  • Melatonin can also be used before going to bed to help with going to sleep. 
  • Occasionally a doctor may prescribe a hypnotic medication for short term use to induce sleep in certain individuals.
  • For some a lifestyle change to minimize work that disrupts sleep maybe warranted if sleep disruption is causing detrimental effects. 

Please see your healthcare provider if you continue to struggle with sleep.

This post was co-authored by John Saieed, Medical Student at the University of Alberta (Class of 2022) and Dr. Yuliya Kolodenko, MD, CCFP. The article was reviewed by Erin Manchuk, BScPharm, BCGP and Stephanie Liu, MD, MSc, CCFP, BHSc.


American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.).

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