Shift Work Disorder: Symptoms, Risks, and Treatments

Shift work sleep disorder is a type of circadian rhythm sleep disorder. The circadian rhythm is the body’s natural or automatic internal clock which regulates the sleep-wake cycle. It responds to light and dark and follows a 24-hour cycle. Hormones such as melatonin and cortisol also play a role in regulating the sleep schedule.

When circadian rhythms are disrupted or out of sync, they can cause problems with sleeping, which can have negative effects on a person’s physical and mental health.

What Causes Shift Work Sleep Problems?

The main cause of shift work sleep disorder is working non-traditional hours outside the regular work hours of approximately 9 am to 5 pm. This may involve an early morning, late evening, or overnight shift or working rotating shifts.   

People suffering from shift work sleep disorder (or shift work disorder, SWD) suffer from sleep disturbances or problems with social or occupational functioning as a result of their shift work.

Prevalence of Shift Sleep Disorder

About 20% to 25% of the U.S. workforce is involved in shift work. However, not all shift workers develop shift work disorder. Evidence suggests that 10% to 40% of shift workers have shift work sleep disorder (SWSD). Studies have found that SWSD is present in: 

• 14% to 32% of night shift workers

• 8% to 26% of rotating shift workers 

• 2% to 5% of the overall U.S. population

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Other Circadian Rhythm Sleep Disorders

Examples of other circadian rhythm sleep disorders include:

• Jet lag disorder due to travel between time zones.

• Delayed sleep phase syndrome (going to bed very late at night and getting up very late in the morning).

• Advanced sleep-wake phase disorder (going to bed earlier than most people and getting up very early in the morning).

• Irregular sleep-wake rhythm disorder (erratic sleep timings).

• Non-24-hour sleep-wake rhythm disorder (a circadian rhythm that is longer or shorter than 24 hours).

Symptoms and Risk Factors for Shift Work Disorder  

What Are The Symptoms of Shift Work Disorder?

The main symptoms of shift work disorder are problems with sleeping, including:

• Insomnia (difficulty falling asleep or staying asleep)

• Hypersomnia (excessive daytime sleepiness)

Other symptoms in shift workers with disrupted circadian rhythms may include:

• Trouble concentrating

• Decreased alertness

• Headaches

• Fatigue or tiredness

• Low energy

• Mood changes such as irritability

• Behavioral changes such as impulsivity, aggression, or hyperactivity

Individual Differences in Shift Workers  

Symptoms of shift work sleep disorder can vary based on different shift work schedules. For example:

• An early morning shift worker who works from 5 am to 1 pm may find it difficult to fall asleep with a lack of nighttime sleepiness.

• An evening shift worker who works from 5 pm to 1 am may have trouble staying asleep.

• A night shift worker who works from 1 am to 9 am may feel excessively sleepy at the end of their shift in the early morning hours or have trouble with subsequent daytime sleep.

Shift Work Disorder vs. Insomnia

The term insomnia refers to trouble falling asleep or staying asleep. It is one of the main symptoms of shift work sleep disorder. 

But while insomnia can be associated with shift work, it can also be due to many other underlying conditions. 

Similarly, shift work sleep disorder can cause insomnia but can also cause other symptoms (see above). Most shift workers have more than one symptom.

Risk Factors: Occupations Impacted by Shift Disorder

Occupations that require shift work that can disrupt the body’s natural sleep-wake cycle include:

• Healthcare: Doctors, nurses, paramedics, and other healthcare practitioners. 

• Public safety: Firefighters, police officers, and other law enforcement officials.

• Transportation: Public transit workers and truck drivers. 

• Maintenance: Maintenance technicians and janitors. 

• Hospitality: Bartenders, restaurant servers, chefs, hotel managers, and housekeeping staff.

• Others: Customer service representatives, factory workers, and grocery store cashiers.

Health Impact in Night Shift Workers: What’s the Connection Between Shift Work and Health? 

A night shift schedule or non-traditional work schedule can cause a range of negative health effects, including an impact on physical and mental health as well as an increased risk of accidents.

What Are The Effects of Shift Work on Physical Health?

• Increased risk of infections such as the common cold and flu

• Obesity

• High cholesterol

• Increased risk of cardiovascular disease

• Gastrointestinal problems

• Low testosterone 

• Fertility problems

• Certain types of cancers

• Worsening of underlying health problems due to lack of restful sleep

What Are The Psychological Effects of Shift Work?

• Mood changes such as irritability 

• Behavioral changes such as aggression, impulsivity, or hyperactivity

• A mental disorder such as anxiety and depression 

• Alcohol abuse and drug use (substance use disorders)

What Are The Other Risks of Shift Work Sleep Disorder?

People who work night shifts or other non-traditional work shifts are at an increased risk of accidents and injuries because of the following symptoms of shift work disorder: 

• Sleepiness at undesirable times

• Drowsy driving

• Sleep inertia (temporary disorientation and decline in performance after waking up from sleep)

• Reduced alertness

• Increased reaction time

• Difficulty concentrating

• Headaches

• Tiredness

• Low energy

How Does a Shift Work Schedule Impact Everyday Life?  

A shift work schedule can impact both sleep and overall health. Disturbed sleep and poor health can affect a person’s everyday life. Many night workers and non-traditional shift workers experience:

• Poor work performance due to problems with focusing and concentrating.

• Relationship difficulties due to mood and behavior changes caused by shift work sleep problems.

• Lack of quality time with family members and friends due to mismatching schedules. 

Diagnosis of Shift Work Disorder  

How Do Doctors Diagnose Shift Work Disorder?  

To make a diagnosis of shift sleep disorder, your healthcare provider may ask you to maintain a sleep journal for at least 14 days. In this sleep diary, you will need to record:

• Your bedtime and wake-up time

• How often you wake up at night

• How long it takes you to fall back asleep

• How rested you feel when you wake up

• Other factors that affect sleep such as caffeine intake, noise, or light

Your doctor may recommend actigraphy (a non-invasive technique to measure activity and rest cycles using a device called an actigraph, which is similar to a watch).

A diagnosis of shift work disorder is made if you have: 

• Complaints of significant sleep disturbance (insomnia or hypersomnia) for at least 3 months associated with a shift work schedule.

• A reduction in total sleep time (the recommendation is for adults to get 7 to 9 hours of sleep in 24 hours).

• A sleep log maintained for at least 14 days, including both working days and off days, demonstrating disturbances in circadian rhythm.

• Absence of other sleep disorders that could explain your symptoms (your healthcare provider may refer you to an expert in Sleep Medicine and/or order a sleep study to rule out conditions such as sleep apnea).

Is Shift Work Disorder a Disability?

Shift work sleep disorder (SWSD) may be considered a disability. It is a chronic medical condition that can lead to other health issues, make it difficult to perform job duties, and increase the risk of accidents. Some workers with SWSD may be eligible for workers' compensation benefits.

How is Shift Work Sleep Disorder Treated?  

Bright Light Therapy

Exposure to a specific type of bright light can help the body’s circadian system adjust to a shift work schedule. If you are diagnosed with shift work sleep problems, your healthcare provider may recommend bright light therapy using a lightbox, light goggles, or desk lamp. They will tell you when to use such a device in relation to your sleep period and for how long to use it, depending on your specific circadian phase shifts. Light therapy is especially useful for night shift workers with sleep disturbance or circadian misalignment. 

Note: Light exposure is also used to treat seasonal affective disorder (seasonal depression that typically occurs in the fall and winter months). 

Melatonin Supplements

Melatonin is a natural hormone that regulates the internal body clock and sleep-wake schedule. Taking melatonin in supplement form can help some people with sleep time misalignment due to shift sleep disorder. However, it’s important to get an accurate diagnosis before taking a melatonin supplement to reset your circadian clock. Learn how much melatonin is safe to take.

Sleep-Promoting Medications

Sleep aids and sleeping pills are sometimes used to treat circadian rhythm disorders such as shift disorder. However, they are only for short-term use to avoid harmful side effects. Notably, some of these medicines are habit-forming and can lead to dependency. Examples include benzodiazepines such as diazepam (Valium) and temazepam (Restoril). Non-benzodiazepine hypnotics include eszopiclone (Lunesta), zolpidem (Ambien), and zaleplon (Sonata).

Learn what medications to avoid while taking sleep-promoting medications.

Wake-Promoting Medications

The U.S. Food and Drug Administration (FDA) has approved certain wakefulness-promoting agents for people with conditions such as narcolepsy (a condition in which there is excessive sleepiness/difficulty staying awake in the daytime). These medicines are also approved to improve circadian adaptation in people with shift work sleep disorder. Examples include modafinil (Provigil) and armodafinil (Nuvigil). 

Note: Wakefulness-promoting agents can also be habit-forming and cause side effects. They are not a replacement for healthy sleep habits and adequate sleep.

Living with Shift Work Disorder: Lifestyle Changes and Tips for Better Sleep  

Changes in Work Schedule

Ideally, the best way to treat shift work sleep problems is to avoid non-traditional or rotating shift work schedules. If you are struggling with sleep loss and other symptoms of shift work sleep disorder, talk to your employer about the possibility of working more regular (traditional) hours. If avoiding shift work is not possible, try the following:

• Avoid working several night shifts in a row. Shift workers working 8-hour shifts should try to limit the number of night shifts to five or fewer in a row. Shift workers working 12-hour shifts should try to limit the number of night shifts to four or fewer in a row.

• Take 48 hours off after a row of night shifts, if possible.

• Avoid working overtime or working longer shifts.

• Avoid long commutes as much as possible, which can eat into your sleeping time. 

• Avoid frequently rotating shifts which are more likely to cause severe sleep disruptions. 

Lifestyle Changes to Manage Shift Work Sleep Disorder  

• If you need to sleep during the day, avoid exposure to bright light in the morning hours. For example, wear sunglasses on your drive home after a night shift.

• Take a short nap of 15-20 minutes before or during a night shift to improve alertness.

• Consume caffeine (in moderate amounts) during your work hours to help you stay alert. Stop caffeine consumption in the last few hours of your shift so that it doesn’t cause problems falling asleep when your shift ends. 

• Avoid driving if you are drowsy. Take a power nap before driving, take public transport, or arrange for someone to drive you from work.

Good Sleep Hygiene: Tips to Sleep Better with Shift Work Disorder  

Many shift workers with a circadian rhythm disorder find that making certain changes to their sleep routine at home helps to alleviate some of the problems related to shift work and sleep. These changes can improve sleep quality and help you in getting enough sleep. To practice good sleep hygiene, do the following:

• Get 7 to 9 hours of sleep in 24 hours to prevent sleep deprivation. 

• Maintain a regular sleep schedule as much as possible. Go to bed and get up at the same time every day, including holidays and weekends.

• Follow a relaxing bedtime routine, such as taking a warm bath, listening to light music, or reading a good book. Avoid looking at screens (TV, tablet, phone) for 1-2 hours before bedtime.

• Create a cool, dark, quiet environment in your bedroom. 

• Avoid caffeine and alcohol in the hours before bedtime. 

• Ask family members to keep the TV or music on low volume and avoid noisy household chores like vacuuming while you’re sleeping.

• Place a “Do Not Disturb” sign on your bedroom door to remind family members it’s your sleep time, especially if you need daytime sleep.

• Schedule deliveries for times outside your sleep hours so the doorbell does not wake you up.