Read the Research: Sleeping Better with Shift Work
Review of - "Is There an Optimal Sleep-Wake Pattern in Shift Work" and the Research that Followed
Welcome to Read the Research Fridays!
Accurate information on shift work and sleep patterns is critical for supporting the health and well being of both workers and those impacted by their work. Research on work-related sleep deprivation have compared its effects to a BAC of 0.10% on the first night, leveling off to an impairment of 0.05% with experience. It’s also linked to depression, obesity, chronic insomnia, and increased risk of cardiovascular disease. With such high stakes, sleep-health for shift workers is extremely important, and requires a critical look beyond just “catchup nights.” We take a look at an earlier study that tries to optimize the sleep-wake shift schedule, and where research has grown from there.
The Optimal Sleep-Wake Study and Findings
Using mathematical modeling and study references, in his 1998 study, Akerstedt predicted the best sleep times for shift workers, especially those on the night shift. We’ll look at the baseline, patterns, and recommendations.
The Baseline Sleep Patterns for Shift Work
The study looked at three sleep-disrupting work shifts: night, morning, and afternoon work. For night work, defined as work between 10:00pm and 6:00am, there’s sleep before a shift, which generally happens as a long afternoon nap, and post-work sleep. Sleep after a night shift usually starts about an hour after work and is 2 to 4 hours shorter than normal sleep, with most of that time-loss in the REM sleep cycle. Naps between shifts are longer and happen more often when post-work sleep is poor quality. It’s common for people working these shifts to feel sleepy or fall asleep at work, especially during the early morning hours. In general, people who permanently work the night shift slept longer (close to 7 hours per day) than people who had rotating shifts (less than 6 hours per day).
In morning shifts (starting at 6:00am or earlier), workers experienced a sleepy feeling throughout the day, had trouble waking up, and were found to sleep 2 to 4 hours less than in normal sleep, with most of the time loss in Stage 2 and REM cycles. Naps at the end of the shift were common and happened more often after poor sleep the night before. Afternoon shifts were found to have less napping, but a later normal bedtime, generally between 11:00pm and 1:00am.
Causes of Daytime and On-the-Job Sleepiness
Scheduling for a night shift already puts a worker at a disadvantage; their work starts after normal peek productive hours and continues through the hours they would normally sleep the hardest. Environmental cues, like exposure to light, work against healthy sleep, and it’s hard to keep the type of routine that makes falling asleep faster. Compounding the problem, night shift changeovers are often scheduled for around 6:00am; this means that not only is the night worker tired, their replacement is starting at a morning shift, meaning fatigue and sleepiness are more likely.
Better Sleep-Wake Patterns
The study looks at a few approaches to encouraging better sleep; the first, and probably most widely used, is to extend the day sleep that happens after a night shift. Modeling the changes of a longer initial sleep show that would reduce time in the “risk zone” for fatigue at work but improve alertness very little. Workers sleeping 5-hours or less during this period would see the most benefit, especially if their post-work sleep is usually under 3 hours.
The next approach is napping – splitting sleep into several shorter blocks, rather than one continuous sleep-period. Napping was found to improve alertness and reduce risk factors, but surprisingly, the timing of the nap mattered more than the duration. The closer the nap happened to the start of work, the more benefit there would be, even if it was less than an hour.
Delaying sleep – fully accepting the nocturnal lifestyle, and timing sleep to end right before the next shiftwork period begins was the last major pattern investigated. For workers permanently on the night shift, forcing oneself to stay awake longer after work, avoiding daylight, and using brighter lights at night may be worth it. In both studies and simulations, after an adjustment period, workers who made this transition had a lower risk-period, alertness similar to day workers, and better-quality sleep. While healthy, following this approach is a huge challenge because if its impact on social and family functions, and the need to maintain consistency during days off. Even for workers on a permanent night shift, it’s common to change back to normal sleep practices on weekends/days off, which can be as disruptive to the circadian rhythm as the transition to day sleep.
Shift Work Sleep Studies and New Research – Where We Are Now
Based on the results of this modeling and overview, we can make a few assumptions. Shift work is bad for sleep, REM sleep suffers more than other parts of the sleep cycle, and the best remedy is trying to be consistent, even if this means staying up longer and setting firm sleeping hours during the day. Does the current research support this? We’ve taken a look at studies citing this model and building on it with further reviews and clinical trials.
Preventive and compensatory measures for shift workers – In Depth Review
This 2003 paper from Peter Knauth and Sonia Hornberger published in Occupational Medicine looks at a range of coping tools for workers who are required to engage in shift work most or all of the time. One big takeaway was that the effects of shiftwork should be spread out throughout the workforce whenever possible to reduce the burden on any one worker. For workers consistently on the night shift, bright lights to mimic sunlight can be helpful in alertness for the first part of the shift, but this light can become fatiguing if used closer to when they expect to go to sleep. Meal breaks are important, and high-protein meals are better than carb-based meals and not eating.
Commuting after shift work can be tiring and dangerous. It’s recommended that employers educate themselves in the challenges of shiftwork and create schedules along with their employees, as well as provide areas in which workers can take short naps if needed before driving.
Cognitive behavioral therapy for shift workers with chronic insomnia
In this 2012 study, researchers looked at work day versus weekend day insomnia, and the effects of CBT on insomnia in 26 shift workers. Participants were offered 6 weekly CBT sessions, followed by a single summary session four weeks after they completed the main series. The study found that, in general, participants slept better on days off than work days, and that the CBT sessions were able to make a significant difference in sleep quality, even with irregular sleep schedules. After therapy and through a 6-month follow up, symptoms of insomnia decreased, the mental health component of quality of life increased, and participants were more rested and fell asleep faster.
Caring for the Country: Fatigue, Sleep and Mental Health in Australian Rural Paramedic Shift Workers
Published in 2012, this detailed study found that shift workers were more prone to depression and fatigue, and were less likely to engage in exercise for self-care. It recommends additional study and support, specifically for first responders, but also any workers who have an inconsistent work schedule. It highlights the need for greater mental health support in addition to sleep hygiene, and coordination with employees when working long, irregular shifts.
Conclusion: Tips for Better Shift Work Sleep
Sleep issues are a very common problem for shift workers and can have a negative impact on health and quality of life. There are some specific recommendations that can help with sleep problems, and at least cut down on the sleep stress from working late and inconsistent hours.
If you have some choice in your shift work rotation:
- Aim for a “clockwise” rotation of hours (e.g. 2 days of morning shifts, 2 days of evening shifts, 2 days of night shifts), with at least two days off following night shifts
- Try to trade off weeks so you have a break from off-cycle shifts, and do no more than 3 morning, evening, or night shifts in a row.
- Space shifts with a minimum of 11 hours off between work
- Plan shift work schedules as far ahead as possible with at least two consecutive days off, and prioritize maintaining a social and work-life balance
If you’re stuck in long-term shiftwork:
- Create a day-night cycle for yourself that matches when you’ll be awake.
- Wear sunglasses driving home
- Try melatonin a couple of hours before you want to fall asleep
- Blackout your bedroom windows with blackout curtains or heavy plastic
- Try to be as consistent in your routine as possible and time sleep to end close to the start of your shift. This may mean staying awake longer after work and staying a bit closer to your weekday schedule on the weekends.
- Consider cognitive behavioral therapy (CBT) geared specifically towards sleep issues to help create a plan and mindset that can help you get the most out of your time sleeping
- Drive safely
- Use your car’s AC
- Vary your driving route
- Listen to your radio
- While at work:
- Avoid large, fatty meals and bring high-protein snacks
- Use bright lighting, especially early in your shift