Shift Work Sleep Disorder (SWSD)

What is shift work sleep disorder (SWSD)?

Shift work sleep disorder (SWSD) is a circadian rhythm sleep disorder that commonly affects people who work nontraditional hours outside the “regular” 9 a.m. to 5 p.m. workday. This could involve overnight, early morning or rotating shifts.

Circadian rhythms are physical, mental and behavioral changes that follow a 24-hour cycle. These natural processes respond primarily to light and dark. Shift work schedules go against most people’s internal body clocks or circadian rhythms.

SWSD causes difficulties adjusting to a different sleep/wake schedule, which results in significant issues with:

• Sleeping when you want.
• Staying asleep.
• Unwanted sleepiness.

About 20% of the full-time workforce in the United States participates in some form of shift work. Not everyone who does shift work experiences SWSD.

How common is shift work sleep disorder?

Shift work sleep disorder is common. It affects 10% to 40% of people who work nontraditional shifts for their job.

What are the symptoms of shift work sleep disorder (SWSD)?

The two main symptoms of SWSD are:

• Insomnia: Insomnia is difficulty falling and/or staying asleep. Insomnia typically affects people with SWSD differently depending on when they work. For example, people with SWSD who work between 4 a.m. and 7 a.m. often have trouble falling asleep, while those who work in the evening tend to have issues staying asleep.
• Hypersomnia: Hypersomnia is excessive sleepiness at unwanted times. This often occurs when a person with SWSD is at work during the night or early morning hours. It can be dangerous and impair work performance.

Other symptoms of SWSD include:

• Difficulty concentrating.
• Headaches.
• Lack of energy.
• Decreased alertness while working.
• Poor mood and irritability.

If you’re a shift worker experiencing any of these symptoms, talk to a healthcare provider.

What causes shift work sleep disorder (SWSD)?

Shift work sleep disorder (SWSD) results from a mismatch between your “internal body clock” and the external environment, which affects the timing and duration of sleep.

Normally, the visual cue of light — specifically, sunlight — triggers your internal clock during a 24-hour day. Light is transmitted through your eyes and into a “control center” of your brain. This leads to a chain reaction of bodily processes and hormones that signal to your body that it’s time to wake up and start your “active” day.

Other cues that significantly contribute to your internal clock include:

• Melatonin: Melatonin is a natural hormone that plays a role in sleep. Your pineal gland in your brain releases the highest levels of melatonin during the night (dark) and minimal amounts during the day (light).
• Cortisol: Cortisol is a hormone that your adrenal glands produce and release. Under regular circumstances, you have lower cortisol levels in the evening when you go to sleep and peak levels in the morning right before you wake up. (Cortisol has several other important roles outside of your circadian rhythm).

For people who work nontraditional shifts, these cues don’t align with their “day” — their waking hours and sleeping hours. This can negatively affect both sleep and wakefulness.

For example, night shift workers frequently sleep during the daylight, precisely when your body’s signals to wake up and stay awake are strongest. As a result, daytime sleep can be short and frequently disrupted. People who work overnight are often sleepy and drowsy while working, as their melatonin levels are usually highest at this time.

How is shift work sleep disorder (SWSD) diagnosed?

A key part of diagnosing SWSD is keeping a sleep journal. Your healthcare provider will likely ask you to keep detailed notes for at least two weeks on:

• When you fall asleep and wake up.
• How many times you wake up while you’re sleeping
• How rested you feel.
• Things that may affect your sleep or sleep routine, like caffeine use and noise disturbances.

Providers typically diagnose SWSD if you experience symptoms for at least three months. Your provider may have you do a sleep study or other tests to make sure your symptoms aren’t due to another condition, such as sleep apnea, or medication side effects.

How is shift work sleep disorder treated?

Although there’s no cure for shift work sleep disorder, several treatments target the core features of SWSD, including:

• Circadian misalignment.
• Sleepiness.
• Sleep disturbances.

The main forms of treatment for SWSD include:

• Changes to your work routine or schedule (if possible).
• Changes to your sleep routine at home.
• Bright light therapy.
• Melatonin supplement.
• Sleep medications.
• Wake promoting agents (medications).

Changes to your work routine or schedule

One aspect of treating SWSD is making changes to your routines and schedule at work. If possible, discuss schedule changes or work adaptations with your employer that can help decrease the effects of SWSD.

Your provider will recommend specific strategies related to the shift you work and your work setting.

Some general tips include:

• Avoid exposure to sunlight in the morning if you need to sleep during the day. Wear sunglasses if you’re driving home or if you have to go outside.
• If possible, decrease the number of night shifts you work in a row. Shift workers working the night shift should limit the number of night shifts to five or fewer, with days off in between. Shift workers working 12-hour shifts should limit work to four shifts in a row.
• After a string of night shifts, take more than 48 hours off, if possible.
• Avoid working prolonged shifts and putting in excessive overtime.
• If possible, avoid jobs with long commutes, which can take time away from sleeping.
• Avoid frequently rotating shifts. It’s more difficult to deal with rotating shifts than it is to work the same shift for a longer period of time.
• If possible, plan a nap before or during the night shift. Naps can improve alertness in night shift workers.
• Consume moderate amounts of caffeine (such as coffee) to help you stay alert while working. Stop consuming caffeine in the later portions of your shift so it doesn’t disrupt your sleep when it’s time to go to bed.
• Avoid drowsy driving. If you’re too sleepy to drive home from your shift, take a power nap first or find a different ride home.

Changes to your sleep routine at home

Most shift workers sleep one to four hours fewer than non-shift workers. It’s important to get at least seven to nine hours of sleep every day.

If you’re a shift worker, you must make sleep a priority. The following tips can help:

• Follow bedtime rituals and try to keep a regular sleep schedule, even on weekends and days off from work.
• At home, ask family and friends to help create a quiet, dark and peaceful setting during sleep time.
• Ask family members to wear headphones to listen to music or watch TV while you’re sleeping.
• Encourage people in your household to avoid vacuuming, dishwashing and other noisy activities while you sleep.
• Put a “Do Not Disturb” sign on your front door so delivery people and friends won’t knock or ring the doorbell.
• Get enough sleep on days off. Practice good sleep hygiene by planning and arranging a sleep schedule and by avoiding caffeine, alcohol and nicotine.

Bright light therapy

Bright light therapy involves exposure to a specific type of light to help your body adjust to your new schedule. You’ll use this light at a specific time, usually at the beginning of your shift. Your provider will tell you when and for how long you should use light therapy.

The light is available as a lightbox, desk lamp or light goggles. They’re similar to the lights that help treat seasonal depression (seasonal affective disorder). Light therapy is especially helpful for night shift workers.

Melatonin

Melatonin supplements may help you adapt better to a shift work schedule. Talk to your provider before taking a melatonin supplement.

Sleep medications

Your provider may prescribe a sleeping pill to help you sleep at appropriate times. Sleeping pills may help you sleep better in the short term, but long-term use can lead to dependency. Sleeping pills can also have unpleasant or dangerous side effects.

Wake-promoting agents

Wake-promoting agents are medications that improve your alertness and your ability to maintain wakefulness. The U.S. Food and Drug Administration (FDA) currently approves two of these medications for SWSD:

• Modafinil (Provagil®).
• Armodafinil (Nuvigil®).

While these medications may help improve performance issues associated with sleepiness, they aren’t a replacement for adequate sleep. These medications also have side effects and may be habit-forming. Talk to your healthcare provider to see if wake-promoting agents are right for you.

Can shift work sleep disorder be prevented?

You may not be able to prevent shift work sleep disorder outside of working traditional working hours consistently. There are steps you can take to manage your symptoms and create a routine that results in better quality of sleep and improved alertness during your waking hours.

What are the complications of work sleep disorder?

If left untreated, shift work sleep disorder (SWSD) can lead to complications, including:

• Poor work performance: People with SWSD often have difficulty concentrating and remembering things while they’re awake and working. This can result in poor performance at work.
• Higher accident risk: SWSD decreases alertness and reaction time. This puts you at a higher risk of making errors or being involved in an accident while at work. You’re also at greater risk of getting into a vehicle accident while commuting due to drowsiness.
• Mood issues: SWSD can make you feel irritable and unable to cope with conflicts. People with SWSD are at higher risk of depression compared to those who don’t have the condition.
• Alcohol and substance use: Many people with sleep problems, including SWSD, self-medicate with alcohol or drugs. This can lead to substance or alcohol use disorder.

Quality sleep is essential to good health. SWSD and a lack of sleep can worsen underlying health conditions or lead to new issues. Increased long-term health risks of SWSD include:

• Getting sick often, such as with a cold or the flu.
• High cholesterol levels.
• Heart disease.
• Obesity.
• Gastrointestinal issues.
• Reproductive issues and/or low testosterone.
• Several types of cancer.

How long does shift work sleep disorder last?

The symptoms of shift work sleep disorder usually last as long as you work nontraditional hours. It tends to go away once you begin sleeping and being awake at more conventional times again. You may have sleep issues even after your shift work schedule ends.

When should I see my healthcare provider about shift work sleep disorder?

If you’re experiencing symptoms of shift work sleep disorder, talk to a healthcare provider about finding a solution that’s right for you.

If you’ve been diagnosed with SWSD and your treatment plan isn’t working after a few weeks, see your healthcare provider.