Home » Sleep Disorders » Shift Work
November 2020 |  Reviewed by:  Shelley Hershner, MD and Seema Khosla, MD

What is shift work disorder?

Shift work disorder occurs when you have difficulties adjusting to your wake and sleep times due to your work schedule. For example, you may need to work at night when most people sleep. Early morning shifts can be a problem too when you have to try to fall asleep before your body is ready. When you have shift work disorder, there is a conflict between your body’s circadian rhythms and your work schedule. You may have to be at work when your body wants to sleep. Then when you must sleep, your body expects to be awake.

People with shift work disorder may sleep up to four hours less than the average worker. Shift work disorder causes you to have trouble sleeping or be severely tired. The quality of sleep may be poor, and you may wake up feeling unrefreshed. You may feel fatigued or have trouble concentrating. This can hurt your performance at work and can put you at risk for making a costly mistake or getting injured on the job.

Not everyone who does shift work has shift work disorder. Many people have difficulty initially adjusting to a new shift. If after several weeks you continue to have difficulty falling asleep or staying asleep, or if you feel tired even after sleeping 7-8 hours, you may have shift work disorder.

The symptoms of shift work disorder usually last as long as you keep the same shift work schedule. The sleep problems tend to go away once you begin sleeping at a more conventional time again. Some people may have sleep problems even after the shift work schedule ends.

Shift work disorder is a circadian rhythm disorder. Your circadian rhythms are your body’s internal clock that signals when you are supposed to feel sleepy or alert. Your circadian rhythms operate on a roughly 24-hour schedule. Your body uses light (and the absence of light) to determine how much of the sleep-promoting hormone melatonin it produces. In shift work disorder, melatonin production may occur when you need to be awake and alert for your job. Exposure to sunlight may prevent you from producing melatonin when you are supposed to sleep.

There are several variations of shift work schedules that can cause difficulties. This includes:

  • Early-morning shifts
  • Night shifts
  • Overnight shifts
  • Rotating shifts

Some people have a more difficult time with certain shift work schedules. Night owls may adjust more easily to working an evening shift than morning-types. Likewise, morning larks may have an easier time with early morning shifts. Many people have difficulty adjusting to overnight or rotating shifts.

What are symptoms of shift work disorder?

Shift work disorder makes it difficult to get enough sleep each day. As a result, you may experience:

  • Excessive sleepiness
  • Difficulty falling asleep or staying asleep
  • Lack of energy
  • Difficulty concentrating
  • Headaches
  • Poor mood and irritability

What are risks of shift work disorder?

Shift work disorder can also increase the risk of:

  • Work-related injuries
  • Mistakes at work
  • Increased use of sick time
  • Accidents related to drowsy driving
  • Substance abuse due to the use of drugs or alcohol to fall asleep

Increased long term health risks include:

  • Frequent infections, colds, and the flu
  • Breast and prostate cancer
  • High cholesterol levels
  • Heart disease
  • Obesity

How to diagnose shift work disorder?

Self test and diagnosis

If you think you may have a shift disorder, ask yourself the following questions:

  • Do you have a schedule that requires you to work when you would normally sleep?
  • Do you have trouble sleeping or are severely tired due to your work schedule?
  • Have you had this work-related sleep problem for at least one month?
  • Does this problem hurt your social, family, or work life?

If your answer is yes to each of these questions, then you might have shift work disorder. The sleep team at an accredited sleep center can provide you with methods to help your body adjust to your work schedule and to improve your sleep.


Before your appointment, the doctor may ask you to keep a sleep diary for two weeks. You will record when you go to sleep and when you wake up, along with how long it takes you to fall asleep, A sleep diary will help your sleep doctor see your habits and give her clues on what course of treatment to take. Your doctor will need to know your complete medical history. Be sure to inform her of any past or present substance, supplement, or medication use.

Normally, a record of your sleep patterns, symptoms, and your work schedule is enough information to make this diagnosis and determine a treatment plan. A sleep study may be needed if the sleep doctor suspects that another sleep disorder, like sleep apnea, may be causing some or all of your symptoms.

How to treat shift work disorder?

Bright light therapy

Bright light therapy involves exposure to a specific type of light to help your body adjust to your new schedule. This light is used at a specific time, usually at the beginning of your shift. Your sleep doctor can help you determine when and for how long you should use light therapy.

The light is available as a lightbox, desk lamp, light goggles, or a visor. They are similar to the lights used to treat seasonal affective disorder. This is especially helpful for night shift workers.

Sleep medications

Your doctor can prescribe a sleeping pill to help you sleep at appropriate times. Sleeping pills may help you sleep better in the short term. Over time, you may develop a dependency or tolerance. Some people may experience side effects when on sleep medications. Talk to your medical provider before taking an over-the-counter sleep aid.

Melatonin

Melatonin supplements may help you adapt better to a shift work schedule. Melatonin is a natural hormone produced by the brain’s pineal gland and a signal for when your body is supposed to sleep. Research suggests that a small dose is just as effective as higher doses. Melatonin should be taken several hours before you plan to sleep. Talk to your medical provider before taking an over-the-counter sleep aid.

Shift work sleep tips

  • If you work rotating shifts, ask your manager to schedule a clockwise rotation. This means that your new shift will have a start time that is later than your last shift. It is easier to adapt to this type of rotation because it is easier to stay up late than to go to bed early.
  • If possible, take a nap during a break in your shift or before reporting for a night shift. Even a nap of just 20 to 30 minutes can improve your alertness on the job.
  • Arrange for someone to pick you up after a night shift or take a bus or cab home. Drowsy driving can put your life and the lives of other drivers at risk. Sunglasses on your way home can help you to fall asleep faster when you get home.
  • Try to keep the same schedule on workdays and days off. Keeping a routine helps your body know when to be alert and when to sleep.
  • Plan for a major change in a shift-work schedule. Begin to alter your sleep time a few days in advance. This will make it easier for your body to adjust. See the example below of a transition from an evening shift to a night shift:
Schedule Sleep time
Evening shift (5 p.m. – 1 a.m.) 3 a.m. – 11 a.m.
Night 1 of transition 5 a.m. – 1 p.m.
Night 2 of transition 7 a.m. – 3 p.m.
Night 3 of transition 8 a.m. – 4 p.m.
Night shift (11 p.m. – 7 a.m.) 9 a.m. – 5 p.m.
  • Use moderate amounts of caffeine to help you stay alert on the job. Stop drinking coffee in the later portions of your shift so that it does not disrupt your sleep when it is time to go to bed.
  • Avoid exposure to sunlight in the morning if you need to sleep during the day. Wear sunglasses if you must go outside.
  • Make sure others in your home are aware of your work schedule. They should keep the home quiet when they know that you need to sleep.