Shift Work Disorder

Ryan Fiorenzi, BS, Certified Sleep Science Coach - Updated on May 29th, 2023

What is Shift Work Disorder?

Shift work sleep disorder (SWSD) is sleep deprivation that is caused by working a job that requires you to be awake at night and sleep during the day. Our brains work on a cycle called circadian rhythm that is set by our exposure to light. When we see light in the morning, it causes us to be awake. At night, our brains produce melatonin (the sleep hormone) that helps us sleep. If you need to fall asleep during the day, it will usually take longer to fall asleep, sleep duration is often shorter, and the quality is lower.

Common professions that use shifts are nurses, respiratory therapists, doctors, firefighters, pilots, flight attendants, police officers, drivers, bakers, military personnel, EMTs, security guards, and factory workers.

SWSD Statistics

  • According to the Cleveland Clinic, around 20% of the full-time workforce in the United States does some kind of shift work, and between 10% and 40% of those shift workers have SWSD.
  • "Night owls" are less likely to suffer from SWSD.
  • Those who are above 40 to 50 years old are more likely to suffer from SWSD.
  • According to a Norwegian study, women are less likely to develop SWSD.
  • The scale to measure people's ability to adapt to shift work called the circadian type inventory. The main 2 factors it measures are an individual's rigidity/flexibility of sleeping habits, and their ability/inability to fight off drowsiness.
  • Other factors that are associated with SWSD are the number of shifts separated by less than 11 hours off, as well as the number of nights worked over the last 12 months.

Health Risks

SWSD can cause many issues on and off the job, including:

  • headaches
  • lack of energy
  • poor focus
  • irritability that can affect relationships
  • higher chance of work-related accidents, as well as driving accidents
  • difficulty managing stress levels-even small stresses can feel like huge stresses
  • drug and alcohol dependency
  • microsleeps, which are 1 to 3 second periods where you fall asleep but don't realize it

SWSD has been associated with certain types of cancer, heart disease, digestive disorders, insulin resistance, metabolic syndrome, depression, anxiety, and menstrual irregularities.

Do You Have SWSD?

Sleep Education provides a simple way to determine if you have SWSD by answering 4 simple questions:

  1. Does your job require you to sleep when it's light out, and be awake when it's dark?
  2. Are you very tired or have issues sleeping because of your work schedule?
  3. Have you had this sleep problem for at least a month?
  4. Does this sleep disorder affect your family, social, or work life?

If the answer is yes, then you'll want to take some steps to improve the amount of quality sleep that you're getting, and speak to a sleep doctor.

If you see a sleep doctor, they may ask you to keep a sleep diary for 2 weeks that will track when you got in bed, how long it took you to fall asleep, and when you woke up. They may then order a sleep study that is sometimes done by taking a monitor home with you, or by spending a night in a sleep clinic.

The Role of Melatonin in SWSD

Melatonin is secreted by the pineal gland, starting about 2 hours before normal bedtime. The pineal gland is a pea-sized gland located just above the middle of the brain that's inactive during the day. For a person who sleeps at night, the maximum amount of melatonin in the system is usually between 3 and 4 am and stops being produced 2 hours before waking up. The rise in melatonin correlates with an increased propensity to sleep, and lack of melatonin is associated with a lack of the ability to sleep.

Melatonin has often been referred to as the "sleep hormone," but the Psychiatric Times purports that it would be more accurate to label it as the "hormone of darkness". Exposure to light stimulates a nerve pathway from the retina to the hypothalamus in the brain. That's where the suprachiasmatic nucleus signals other parts of the brain to make changes in hormone levels, body temperature, and other functions.

In the morning when the eyes are exposed to light, a series of events occur that include increased body temperature and increased cortisol levels. Cortisol is a stress hormone that helps facilitate activity and prevents sleep.

Exposure to anything more than dim light will inhibit the production of melatonin. The National Sleep Foundation has referred to melatonin as the "Dracula of hormones," as it only occurs at night. Your pineal gland can be switched on by your internal clock, but if it's not dark, it won't produce melatonin.

Melatonin is the only hormone that's available for purchase without a prescription in the United States. It's naturally contained in some foods (such as tart cherries, rolled oats, and bananas), so it's sold as a dietary supplement.

Evidence suggests that taking melatonin is effective for resetting the circadian rhythm, but not for regular use, like a sleeping pill. Some research has shown that it's effective for reducing the amount of time it takes to get to sleep, and it reduces the number of awakenings throughout the night, but it doesn't look to increase the amount of sleep time.

Research indicates that melatonin production increases with lower temperatures. This may be because of the association of lower temperatures with less daylight or may be related to the fact that melatonin is an antioxidant. An antioxidant neutralizes free radicals, which damage and even kill cells.

Melatonin also helps cell repair during sleep, as well as stimulates the body to produce other antioxidant enzymes. Scientists theorize that people with SWSD have higher rates of several diseases due to this lack of repair of cells and "house cleaning" that's supposed to occur at night.

How to Manage SWSD

To be able to stay awake at night, many people rely on caffeine, though there are many other techniques to help reduce the effects of SWSD.

  1. Try to keep the same sleep schedule. Many sleep experts believe that the most important part of sleep hygiene is to fall asleep and wake up at the same time every day.
  2. Take a 90-minute nap before your shift. We sleep in 90-minute cycles, and if you wake up at the end of a cycle, you will be less groggy.
  3. Take a 15-minute nap during the day, and/or during a work break. If you wake up before you start going into a deeper phase of sleep, you'll wake up refreshed, not groggy, and you will have made up some of your sleep debt.
  4. Create an ideal sleep environment that blocks noise and light.
  5. Expose yourself to bright light early in the shift at night, which tricks the brain to stay awake.
  6. Reduce your bright light exposure in the morning. You can wear dark goggles or blue-blocking glasses. Blue light is the part of the light spectrum that tells the brain to be awake.
  7. Take melatonin. The American Association of Sleep Medicine recommends that a dose of 0.5 mg is as effective as higher doses. Some doctors have expressed concern that long-term use could cause dependency, or that the body would stop producing it on its own, but there's so far no evidence to back up those concerns.
  8. Reduce your stress levels.
  9. Reduce caffeine for several hours before bedtime.
  10. Avoid alcohol and nicotine. Though alcohol may help you get to sleep faster, it may reduce the overall quality of sleep.
  11. Exercise regularly.
  12. Eat a healthy diet, and incorporate foods that help induce sleep.
  13. Talk to your doctor. They may prescribe modafinil (Provigil), which has been approved by the FDA to help wake people up. As with any pharmaceutical, be very careful with side effects and dependency.
  14. If you're on a rotating shift, ask your manager to schedule a clockwise rotation, which means that your new shift will start later than your last shift. This is easier to adapt to because it's easier to stay up later than get out of bed earlier.

For some people shift work causes no issues. For others, it can cause serious health and life issues. If you're one of those people, try to find a long-term solution by getting onto a schedule where you can sleep at night and work during the day.

Many companies make the newest employees with the least seniority work the shifts that negatively impact sleep. If you're in this situation and are on schedule to go back to a shift that's better for your sleep schedule in a few months to less than a few years, try these strategies to increase the amount of restful sleep. If there's no end in sight, talk to your boss about modifying your schedule, and if that's not a good option, look into a change of companies, or a change in your job.