I recently had a heated discussion with my mother. She insisted that she had read somewhere that the best time to go to sleep is between 9 and 10-o-clock at night. My mother does know what I do for a living, but somehow, this bit of information had rooted itself into her psyche beyond the reaches of my counterarguments. Sure, 10-o-clock is a reasonable bedtime; there’s nothing wrong with it... but what if you have to go to work at midnight?
Sleep tips are everywhere. News articles, wellness blogs, wearables, smartphone apps, and your mother are seemingly always ready to give you advice on how to get the best sleep ever. Tips on healthy sleep behaviors, also called “sleep hygiene”, usually include going to bed at the same time every night, having a wind-down routine prior to bed, and limiting exposure to light or screens in the bedroom, etc. Most often, tips are geared towards sleepers who work a traditional 9 to 5 daytime job. Shift workers may find sleep tips geared towards non-shift workers to be inapplicable or just annoying. Ironically, shift workers are one of the populations that would benefit the most from sleep hygiene tips if only those tips could be tailored to their lifestyle experience.
Shift work refers to any work schedule that falls outside the hours of 0700 (7:00 AM) and 1800 (6:00 PM). Shift work can be fixed, meaning that the employee works the same set hours without change, or rotating, meaning that the time at which a person starts and ends work changes. For example, a worker on a rotating shift may work from 2200-0600 (10:00 PM to 6:00 AM) for two weeks, then switch to a schedule that starts at 0600 and ends at 1400 (2:00 PM) for the next two weeks. Shift work can start in the morning, afternoon, evening, or night. A single shift can be shorter than 8 hours or last for days on end. Workers who are on-call for multiple days in a row, such as firefighters, emergency medical services (EMS), offshore rig workers, or military personnel, frequently live and sleep on-site during this period. Sleep time is not always guaranteed, and sometimes, even schedules that allow for sleep may be counterintuitive.
A good example of a counterintuitive on-off work schedule is the rotating 5-h on/10-h off (5/10 or “five and dime”) schedule seen in military maritime. Sailors and maritime workers on this schedule don’t have the opportunity to sleep around the same time each day but rather exist to operate on a 15-hour continuous cycle without weekends or extra recovery time (1). Working for 5 hours and then having 10 hours off, on repeat, doesn’t add up to a 24-hour day. A funny thing about earthlings is that we evolved on a planet with a day/night cycle that circles the sun every 24 hours. I say, “earthlings” rather than “humans” or “people” because this is true of every living organism native to the planet Earth. Modern society is a little more loosey-goosey about following a 24-hour, active-during-the-day, sleeping-at-night schedules than is… say… the actual genetic material making up our biological bodies! (2). Shift work is so disruptive to the biological system that shift workers can be diagnosed with their own special sleep disorder—Shift Work Sleep Disorder (SWSD) (3-4). Hallmark symptoms of SWSD include excessive daytime sleepiness, insomnia during normal sleep times, gastrointestinal problems, and an increased risk for cardiovascular disease.
If shift work is so disruptive to sleep, and common advice about sleep hygiene doesn’t work well with the shift worker’s lifestyle, what can we do? Some general sleep tips can be modified to work for individuals who can’t sleep at the same time every day or have to go to sleep during daylight hours. A pre-bedtime wind-down routine, for example, can help you relax at any hour of the day. A wind-down routine is a set of calming activities you perform in the same order before going to bed. The routine sends a message to your brain that it’s time to go to sleep. For more information on developing a wind-down routine, check out https://www.sleepfoundation.org/sleep-hygiene/bedtime-routine-for-adults. A game-changer for getting better sleep during daylight hours is using a sleep mask or blackout curtains to darken your bedroom (5-6). If you have to wake up when it’s still dark out, blast yourself with bright lights in the bathroom or while you get ready. Polychromatic light (like an incandescent bulb) has a more pronounced effect on alertness than monochromatic light (7) (like LEDs), but work with what you’ve got. Treat caffeine the same way—take it to wake up, avoid it to fall asleep. Another good tip for shift workers is to tell your friends, family, or co-workers not to bother you while you’re trying to sleep. Put a “Do Not Disturb” sign on the door, set your phone to silent, or try earplugs.
Shift workers may also find that using a personal sleep tracker, like a Fitbit or other smartwatch device, helps them visualize their sleep patterns and identify areas to make improvements. A caveat here is that sleep trackers are designed for the average healthy daytime worker. Not all sleep trackers will record short sleep, like naps, or sleep occurring during the day. Sleep hygiene tips that pop up in-app might be irrelevant as well. For the best use of a sleep tracker or app, look for one geared towards shift workers. For example, IBR is developing an iOS mobile app called SleepTank®, that can help workers in 24/7 operations manage their sleep needs regardless of time of day. The app is compatible with Fitbit devices; we hope to expand to more platforms in the future. If you are interested in learning more about SleepTank®, using SleepTank® as a behavioral intervention, or helping IBR test the efficacy of SleepTank® in operational environments, please contact email@example.com.
Organizations can help improve shift worker sleep by adjusting schedules and improving the work environment. To return to the example of maritime shiftwork, researchers at the Naval Postgraduate School compared Sailors’ health and alertness between 5/10 schedules and a fixed 3-hours-on, 9-hours-off fixed schedule that aligns with a 24-hour day. They found that Sailors on the 3/9 schedule had less daytime sleepiness, better mood, and faster reaction times than Sailors on the 5/10 schedule (8). Fixed shifts are generally considered better for shift worker sleep than rotating shifts, and forward rotating shifts (going from a morning shift to an afternoon shift) are considered easier to adapt to than backwards rotating shifts (going from an afternoon shift to a morning shift) (9). Organizations can increase worker alertness by using polychromatic lighting instead of monochromic lights, and improve sleep for on-site workers by providing a dark, quiet, comfortable sleeping area in which they can rest. SAFTE-FAST is another tool that can help organizations identify areas of fatigue risk in their shift schedules.
Because shift work is a diverse catch-all to describe patterns of work across a variety of industries, it is difficult to come up with a generic set of tips that apply to every case. One of the things that IBR and SAFTE-FAST team strive to do is tailor interventions to meet the needs of the specific industry or organization for whom we are doing a fatigue risk assessment. There isn’t space in a blog post to drill down specific recommendations for every kind of shift work, but I hope these few tips have been helpful. No matter how or when you’re working, perhaps the best tip is to remember that sleep is important and that fatigue is a health and safety risk.