Your body has an internal clock—a circadian rhythm—that controls when you sleep and when you wake. One of the most powerful external factors on your internal clock is sunlight. When the sun goes down, your brain and body begin preparing for sleep.
Most of us have jobs that align with this natural circadian rhythm; we work during the day and sleep at night. But about 25 percent of people in the U.S. labor force are shift workers, meaning they work evenings, nights and early mornings.
For some people, adjusting to a nighttime work schedule is relatively easy. Others struggle with the change.
“The demands of the job sometimes don’t match with the internal circadian rhythm,” says UNC Health pulmonologist and sleep medicine physician Adnan Pervez, MD, who is medical director of the UNC Rex Sleep Disorders Center. “This misalignment of the internal clock can lead to poor functioning on the night shift and poor sleep during the day.”
We spoke to Dr. Pervez about how shift workers can stay alert on the job and get adequate sleep during the day, and when they need to consult a doctor about their sleep routine.
Staying Awake During the Night Shift
If you’re working overnight, Dr. Pervez recommends that you consider taking a nap before the start of your shift so you’re well-rested at the beginning of the night.
“Then, if your work allows or accommodates it, you may try to take a shorter nap during your shift, around 20 to 40 minutes,” he says. “Longer naps can lead to you entering deep sleep, and it can be difficult to function immediately when waking up from deep sleep.”
At the beginning of your shift, you can have a small amount of caffeine, such as a cup of coffee or tea. Limit caffeine to the earlier parts of the shift rather than having it throughout the night. That will help you get to sleep more easily afterward.
Throughout the shift, take short breaks to stretch or walk to stay alert. Avoid foods that are high in sugar and fat, which can be difficult to digest and cause dips in energy. Your circadian rhythm affects digestion, and the timing and content of meals can also affect your sleep, so you may want to avoid large meals at night and instead focus on more frequent smaller meals or snacks that are high in protein and fiber.
Protecting Sleep During the Day
After your night shift is over, you need to focus on getting quality sleep. Your commute home in the morning may be in the rising sun, which will prompt your body to think it should be awake, no matter how tired you are.
The goal is to reduce your exposure to light in the morning, which Dr. Pervez says is the most important environmental cue regulating the sleep cycle. “Wear sunglasses on your drive home,” he says. “Once you return home, use darkening shades on windows.”
Then, begin preparing for sleep.
“Have a wind-down routine, just as people who work the day shift do in the evening,” Dr. Pervez says. “Don’t engage in vigorous exercise. Have a small snack if you’re hungry, but avoid a big meal. Don’t rely on alcohol; it may induce sleep, but it causes more sleep fragmentation.”
Tell your partner and other family members when you’ll be sleeping so they can minimize noise and distractions.
“Family responsibilities will have to be scheduled around your need for sleep,” Dr. Pervez says. “You may not be ready to drive kids around or do housework right after a night shift. You have to protect daytime sleep like you do nighttime sleep.”
Dr. Pervez says your internal clock may wake you in the early afternoon, before you’ve gotten enough sleep. That makes a nap before a night shift especially helpful.
If you regularly work night shifts, try to stick to this schedule even if you have a night off. Constantly changing your sleeping and waking times confuses your body clock and makes it harder to stay alert when you work.
Understanding Shift Work Sleep Disorder
If you have trouble functioning during a night shift or difficulty falling asleep at times that are designated for sleep, you may have shift work sleep disorder.
“Shift work sleep disorder is a type of circadian rhythm disorder that can seriously affect your quality of life,” Dr. Pervez says.
A sleep medicine physician can assess your overall health to diagnose the condition and offer strategies to help you cope.
“We can write a prescription for a nap, which you can share with your supervisor,” Dr. Pervez says. “There are also medications that improve wakefulness. They are only available by prescription, and you need to see a doctor who is familiar with your situation.” Timed exposure to bright light during the night shift, particularly earlier in the night, can also help align your internal clock with your work schedule.
Careful use of medications to help you sleep after the night shift may be an option, but Dr. Pervez advises checking with a doctor first.
Even if you don’t have shift work sleep disorder, be aware of other health risks of shift work, and talk to your doctor about precautions to take.
“Motor vehicle accidents in the early morning hours are a tangible risk,” Dr. Pervez says. “There’s also an association between shift work and issues like anxiety and depression, and shift work is associated with an increased risk of obesity, cardiovascular disease and cancer, but the mechanism of those connections is still under study.”
Employers can help shift workers by being mindful when setting schedules. If shifts change, they should move in a clockwise fashion (afternoon shift to evening shift to night shift) rather than counterclockwise (night to evening to afternoon).
“A rotating schedule with varying shifts makes it harder to establish a sleep schedule and stay on it,” Dr. Pervez says. “The more predictable the schedule, the better.”
Having trouble sleeping? Talk to your doctor. If you need a doctor, find one near you.