Shift work sleep disorder

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at January 9, 2017
StartDiseasesShift work sleep disorder

Shift work sleep disorder is a type of circadian rhythm sleep disorder that affects people who work at night or who have rotating shifts in which they work at night some of the time and work during the day at other times. It causes excessive daytime sleepiness. It is also known as shift work disorder.


Definition & Facts

Up to 20 percent of the population engages in shift work in which a person works at night or rotates, working a night and day shift. Workers that commonly work nights are maintenance and cleaning crews, security guards, doctors, bakers, and cops. Shift work sleep disorder occurs when the body's internal clock or circadian system causes sleepiness when a person is at work and/or wakefulness when a person is needing to sleep.

The circadian system is the body's internal clock which regulates the release of hormones, digestion, and sleep according to a 24-hour cycle. It takes its cues from external factors such as sunlight and eating. Circadian rhythm sleep disorders involve a discrepancy between the circadian system and these outside factors. Examples of other circadian rhythm sleep disorders include advanced sleep phase disorder, delayed sleep phase disorder, and non-24-hour sleep–wake disorder.

Excessive daytime sleepiness is the leading reason why people seek treatment at sleep clinics, and it can be caused by shift work sleep disorder. Excessive daytime sleepiness interferes with the capacity to function in daily life, including fulfilling work obligations and partaking in hobbies.

Shift-work sleep disorder can be a serious condition in that it can increase the risk of workplace accidents and automobile accidents as well as cardiovascular disease and other health conditions.

Symptoms & Complaints

Excessive daytime sleepiness is a major complaint of shift work sleep disorder. A person with this condition experiences difficulty concentrating, headaches, lethargy, and persistent drowsiness. He or she does not feel refreshed after getting amounts of sleep that others find adequate.

Cognitive deficits such as impaired memory occur. The capacity to study, be productive, or socially interact is compromised. Irritability and mood swings are also symptoms of this condition. Depression may also be a symptom. If a person is unable to socially engage with their family or friends due to their sleep disorder, it can cause or exacerbate an existing mood disorder.

In addition to excessive daytime sleepiness, people with this condition can also experience insomnia in which they find that they cannot fall asleep or they wake up too quickly without achieving 7-9 hours of sleep. An increased risk of developing a cardiovascular disease is linked to sleep disorders such as an increased risk of obesity, stroke, and blood clot.

Shift work sleep disorder can also lead to the abuse of stimulants in an attempt to stay awake. This can lead to a host of other health problems. People with this condition may also be at a higher risk for certain cancers.


Shift work sleep disorder involves a conflict between the body's circadian system and a person's work schedule. Because the circadian system relies on external cues like sunlight, it promotes sleepiness by producing melatonin at night when a person is working. Therefore, a person finds it difficult to concentrate and be productive while working a night shift.

Though frequently occurring among those who work nighttime, rotating, or overnight shifts, this disorder can affect people who work early morning shifts as well. People who are predisposed to staying up late are more likely to be negatively affected by an early morning shift. It is more common among people over the age of 50.

Diagnosis & Tests

The diagnostic process involves the health care professional inquiring with the patient about his or her symptoms, medical history, and family history. He or she will also perform a physical examination.

A sleep diary can be utilized to track a person's sleeping patterns over a period of weeks. The Epworth Sleepiness Scale is a self-diagnostic tool that measures a person's drowsiness levels during different activities. A multiple sleep latency test measures how quickly a person falls asleep.

Symptoms will have had to persist for a month, and the absence of sleep problems prior to or independent of a person's work schedule will need to be established in order for a diagnosis of shift work sleep disorder to be rendered.

Sleep studies or polysomnography which are typically performed overnight tracks a person's functions while they sleep. This test can help rule out sleep apnea. It measures how a person breathes while sleeping, the movements they make while sleeping, their heart rate and their brain activity.

Treatment & Therapy

Adopting proper sleep hygiene practices can help promote rest and treat or stave off shift work sleep disorder. These practices include limiting caffeine or stimulant use in the hours preceding sleep, creating a relaxing environment in one's bedroom, having a relaxing and consistent routine prior to sleep, using curtains to block out all light if sleeping during the day, and using a sleep mask to block out light.

In the event that sleep hygiene practices are inadequate, there are various medications that may be able to promote wakefulness on the one hand and promote sleepiness on the other. Modanifil is a stimulant that is used to reduce excessive daytime sleepiness among those with this condition. Unlike amphetamine, it does not pose a significant risk of abuse or addiction.

Certain sedatives can help promote sleep during the day, including zolpidem. Benzodiazepams can also promote sleep, though these carry the risk of serious side effects and may be habit-forming. Melatonin supplements may be able to assist in promoting sleepiness. Antidepressants may offer assistance as well in promoting healthy sleep habits.

Sleep disorders are often the result of side effects from medications, so medications will have to be carefully prescribed when treating shift work sleep disorder.

Prevention & Prophylaxis

There are various measures one can take to avoid sleep problems associated with shift work. These can include limiting the amount of night shifts worked in a row. Using bright lights in one's work environment can help promote wakefulness and alertness. When trying to sleep during the day, one should avoid sunlight and even wear sunglasses to limit the intake of sunlight.