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Can Working Night Shifts Cause Insomnia?

by Dale Cudmore | Updated: Jul 04, 2021

Shift work puts people at a greater risk of developing circadian rhythm sleep disorder (also called shift work disorder).

It’s a condition recognized in the International Classification of Sleep Disorders, and its main symptom is insomnia and excessive sleepiness.

We’re going to go over the research behind shift work and sleep issues shortly, but know that the main cause is the disruption of the circadian rhythm (which controls when and how we sleep).

By not getting normal exposure to sunlight, the circadian rhythm can be thrown off and cause all sorts of sleep issues.

Let’s look at this in more detail, and how insomnia in night shift workers can be treated.

How Common is Insomnia For Shift Workers?

If we put together a variety of studies, we can see that shift work disorder occurs in roughly:

  • 32-37% of night shift workers (1)
  • 8-26% of rotating shift workers (1, 2)
  • 10% of day workers (3)

In other words, the more night shifts someone works, the more likely it is for them to develop insomnia as a result of this disorder.

Rotating shifts (between periods of night and day work) are slightly better, but some people adapt to them better than others.

Does Insomnia Severity Differ for Night or Day Shift Workers?

One other relevant question is whether or not night shift workers suffer the same severity of sleep troubles in most cases.

One study looked at this topic in great detail, with a sample of 418 adults of all types of work (4). They found:

  • Insomnia in both night and rotating shift workers had a similar profile to that of insomnia in day workers.
  • Overall sleep time was related to the degree of insomnia, but not the type of shift work.
  • Night workers with insomnia reported higher scores in overall pain and lower scores in social life.

So while some of the consequences of sleeplessness might be worse for night shift workers, there’s nothing too different from “normal” insomnia cases.

Consequences of Night Shift Insomnia

If someone works night shifts for years and develops sleep issues, research shows that those sleep issues are likely to continue even after shift work stops (5).

Most symptoms of insomnia in night shift workers are the same as the regular side effects of insomnia (6):

  • Anxiety
  • Depression
  • Fatigue

In addition, one study showed that constant night shifts are the worst for health (7):

Among all shift types, workers with fixed night shifts were found to have the shortest duration of sleep, highest level of burnout score, and highest prevalence of insomnia and minor mental disorders.

Burning out is a particularly interesting symptom, as it means that insomnia in this case doesn’t negatively affect just mental and physical health, but also career (financial) health.

Treatment for Shift Work Insomnia

The typical treatment prescribed for insomnia by doctors is cognitive behavioral therapy (CBT-i) and sometimes sleep medication. While those might help a bit, they will not fix circadian rhythm sleep disorder because they don’t treat the underlying issue (lack of proper light exposure).

Recent research has shown promising results from using bright light therapy for insomnia.

One study exposed night shift patients to bright light during the first half of their night shift, and then gradually reduced it throughout the morning, with good outcomes (8):

The Insomnia Severity Index (ISI), Hospital Anxiety Depression Scale (HADS), and subscales of the HADS scores were significantly improved in the treatment group as compared with the control group.

A simple graph makes the results really clear:

On top of light therapy, proper sleep hygiene is also crucial.

During the day, there’s typically more light and noise pollution that can disrupt sleep, which means that things like blackout curtains and even ear plugs are even more important in many cases.

Summary: Insomnia and Night or Rotating Shifts

Night shifts, and even rotating shifts, put people at a great risk of developing insomnia as a symptom of circadian rhythm sleep disorder.

Approximately 1 in 3 night shift workers develop this disorder, and it can lead to long term issues with sleep.

For now, research suggests that adding light therapy to a traditional insomnia treatment plan (created and supervised by a medical professional) is the most effective way to address this disorder.


  1. Shift Work Disorder in Nurses – Assessment, Prevalence and Related Health Problems
  2. Shift Work Disorder in a Random Population Sample
  3. Shift Work Sleep Disorder: Prevalence and Consequences Beyond that of Symptomatic Day Workers
  4. Insomnia in shift work
  5. Sleep Quality of Former Night-shift Workers
  6. Insomnia Induced by Night Shift Work is Associated with Anxiety, Depression, and Fatigue, among Critical Care Nurses
  7. Night shift and rotating shift in association with sleep problems, burnout and minor mental disorder in male and female employees
  8. The Effectiveness of Light/Dark Exposure to Treat Insomnia in Female Nurses Undertaking Shift Work during the Evening/Night Shift

Medical Disclaimer: The information on is not intended to be a substitute for physician or other qualified care. We simply aim to inform people struggling with sleep issues about the nature of their condition and/or prescribed treatment.

About the authorDale is the founder of Snooze University and a sleep researcher. I overcame my sleep issues and now I'd like to help you do the same by summarizing the latest sleep studies for you.