Shift work and sleep

Introduction

In this guide we suggest some practical steps to take if you need help to cope with shift work, the scientific explanations for why sleeping during the day is so hard, and how to get the most from the Sleepio program if you are a shift worker.

Why does shift work make sleeping so difficult?

1. Sleeping against the body clock
The body has an in-built biological rhythm which keeps you alert during daylight hours. When you try and sleep during the day it takes longer to drift off and you’re much less likely to have 7-8 hours of deep, uninterrupted sleep.

2. Irregular schedules
People with routine wake-up and sleep times produce hormones which act as signals for the body to sleep or to wake according to 24 hour cycle. The more often you switch your schedule, the harder it is for the body to anticipate. It’s particularly tricky for shift workers with different routines on work and rest days.

3. Sleeping out of sync with people around you
Staying asleep with the noises of daytime hustle and bustle around you can seem impossible. Even if you can find peace and quiet, family responsibilities and personal relationships often mean sleep gets pushed lower down the priority list.

On average, night shift workers sleep for 2 hours less than the average adult. This sleep debt puts shift workers at more risk of accidents and increases long term health risks. Read on for strategies to help you to minimize your sleep debt.

Find the right shift pattern for your body clock

Fixed vs. rotating shifts

In an ideal world, we’d all work during daylight hours, but if that isn’t possible, it’s generally better to stick to a stable routine for at least two weeks at a time than to rotate more frequently. Rotating shifts are like a state of perpetual jet lag (without the air miles). The more time you have to adjust between different shift types, the better.

Rotate clockwise

Most people have a natural sleep-wake cycle of just over 24 hours, and find it easier to adjust to extend wake time than to cut it short. This means it’s less disruptive to move from daytime shifts to evening shifts, and then to night shifts.

Extended shifts need extended recovery

Extended duration shifts, which involve working for more than 8 hours, are typically associated with more sleepiness and a higher risk of accidents. However, researchers have shown that one 12 hour day shift, followed by 24 hours of free time, then one 12 hour night shift and two full rest days, results in similar levels of sleep, safety and fatigue to 8 hour shifts (Fischer et al. 2016).

Larks vs. Night owls

If you’ve always woken up early and feel energized in the mornings, you will probably find it easier to adjust to early morning shifts than a natural ‘night owl’. If your employer can be flexible, ask to experiment with different shift types for at least a month at a time. When you find one that suits you, ask if you can stick with it.

Is there another option?

Some people find it easier to adapt to working shifts than others. If your internal clock has a hard time adjusting, be especially careful to protect your sleep time and investigate whether you could work a regular day shift.

Optimize your schedule for night shifts

Even if you can’t change your shifts, what you do before, during and after the shift can make a huge difference to your sleepiness and your general mood. These tips can be helpful for both night shifts and late shifts. Look down the list for things that are in your control. Test out what works for you, and try to do it more often.

Before your night shift:

• Most people can cope with up to a 2-3 hour shift in their sleep-wake cycle. If you have a few days before you start night shifts, gradually taper your sleep and wake times towards the new schedule, for example, by rising 2 hours later each day and going to bed 2 hours later.
• Take a nap before your shift to reduce sleepiness when you’re at work.
• If you’re a natural early bird, try a long nap for up to 3 hours to reduce your sleep debt. If you’re a night owl, you’ll find it more difficult to sleep in the afternoon but try at least a 15-20 minute nap before you get ready for work.
• Be aware that if you nap for more than 30-40 minutes your body will enter deep sleep. The advantage of deep sleep is that it will help to reduce a sleep debt, but it can take around an hour to be fully alert again, so allow time to wake up afterwards.

Staying alert while you’re at work

• Seek out bright light before and during the early part of a night shift. Even if work areas need to have dim light, break areas should still be well lit. If your workplace feels too dark, speak to your employer about increasing the brightness of the lighting.
• When you have the same shift for at least a few days, eat a meal or snack at the same time each day to promote regular body cycles. If you working nights for several days, eat ‘lunch’ mid way through your shift.
• A mid shift power nap of up to 30-40 minutes is more effective than coffee for improving alertness.
• Caffeinated drinks like tea and coffee can be helpful stimulants to promote attention in the first half of a shift, but taken within a few hours of bedtime could result in a longer time to fall asleep, reduced deep sleep and fewer sleep hours.

Getting home after your night shift

• Do you need to drive? You are at higher risk of having a car accident if you drive after a night shift. If public transport, carpooling or cabs aren’t practical, vary your route home so that you’re less likely to be driving on ‘autopilot’. If you’re very tired, take a short nap before setting off.
• Daylight is a signal to the body to stay awake. Wear dark glasses on the way home to encourage the production of melatonin and prepare the body for sleep.

Protecting your sleep after a night shift

• Follow the same routine to prepare for bed on day or night shifts. This will encourage pattern recognition and get the body ready for sleep – a light snack, a warm bath, brushing your teeth, soothing music, relaxation exercises or meditation could be part of a wind down routine.
• Avoid having a clock or alarm clock where you can see it during your rest time. Looking at the time may make you feel anxious.
• Use blackout curtains or drapes to make your bedroom as dark as possible. Alternatively, a good eye mask may do the trick.
• If you live in a noisy environment, look at soundproofing your bedroom with double-glazing, carpets, heavy curtains and even wall insulation. Ear plugs could also help to preserve your peace and quiet.
• Keep a visible record of your sleep and work schedule somewhere so your partner, family or housemates can see it, so that they don’t inadvertently wake you up.

Recovering between shifts

• Try and find time for exercise. If you can stay physically fit, your body will be better able to cope with changes to the body clock, and you’ll feel less fatigued overall.
• If you’re trying to return to a natural day shift pattern, remember that bright light boosts alertness. Light alarm clocks and light boxes that mimic the sun’s spectrum and intensity can help to reset wake cycles (aim for ~2500 lux vs. normal lighting of ~150 lux).

Recognize Shift Work Disorder

• Does your regular shift work schedule interfere with sleeping during the night?
• Do you experience difficulties sleeping or excessive sleepiness?
• Have you experienced sleep problems for 3 months or more?

If you answer yes to all three of these questions, you may be experiencing Shift Work Disorder (SWD). According to the International Classification of Sleep Disorders, ICSD-3, SWD is a chronic problem of of excessive sleepiness or disturbed sleep as a consequence of shift work. It is often associated with lack of energy, difficulty concentrating, headaches and irritability.

SWD is very common – it is thought to affect between 10 and 38% of rotating and night shift workers, or up to 5% of the general population.

There are other explanations for extreme sleepiness, and before diagnosing SWD, a sleep expert will ask you to use a sleep diary to record your sleep for at least 14 days, including work and rest days, and will look for alternative causes.

If you are concerned that SWD is impacting on your health, safety, work or family life, ask your doctor, or a sleep expert for advice. After taking a sleep history, a sleep expert will be able to advise on how to optimize your personal schedule, including light exposure, and potentially the use of medications.

Sleepio for shift workers

The Sleepio program is based on cognitive and behavioral techniques, and utilizes proven strategies to address the cognitive (or thought-related) and behavioral (lifestyle and schedule-related) reasons that lead to being unable to sleep.

Sleep improvement techniques for all
All the cognitive tools and techniques in the program, such as those to tackle the ‘racing mind’, will be useful for everyone who is worried about getting enough sleep. Relaxation techniques such as Autogenic training and Mindfulness can help you get to sleep at any time of day or night. Lifestyle advice about the role of exercise and alcohol, for example, will be relevant to everyone, regardless of what time they go to sleep.

Adaptations for shift workers
Sleepio also includes a daily Sleep Diary and scheduling tool. These were designed to help long term poor sleepers adopt regular sleep and wake routines. These tools assume that you can choose what time you go to sleep at night, so are less relevant to shift workers. Below we suggest some simple adaptations you can make in order to track your progress.

Many shift workers have successfully completed the program. Sleepio’s ‘Graduates’ often share tips and advice on Sleepio’s online community. If you’d like help with personalizing the Sleepio program, we highly recommend asking questions in the Shift Work discussion, or joining the weekly sleep expert session.

Session by session advice on adapting Sleepio for shift workers

Sleep Test
The program starts with a detailed questionnaire about your typical sleep patterns over the last 2-4 weeks. This can be hard to answer when sleep is heavily dependent on your shifts. If possible, take a mental ‘average’ of your recent sleep pattern. Alternatively, choose your most common shift pattern, or your typical rest day schedule. The important thing is that you can compare your progress over time, so keep a note of the reference schedule you have used to answer these questions.

Core Session 1: Sleep Efficiency adaptation
The Prof will calculate your Sleep Efficiency, the proportion of time in bed you spend asleep. The Sleep Diary assumes that you sleep in one block during the night. If you typically sleep in two or more blocks (such as a post-shift 4hr sleep, and a pre-shift 3-hr nap) add the combined blocks of time together when you complete the diary. Although the clock time you go to sleep will be inaccurate, you will still be able to track your total hours of sleep time, and Sleep Efficiency over time.

Core Session 2
Progressive muscle relaxation will be a useful tool to help you get to sleep at any time of day or night. Sleep hygiene or lifestyle advice is all relevant for shift workers.

Core Session 3
Poor sleepers are advised to strengthen the bed-sleep connection by getting out of bed if they cannot sleep for 15 minutes or more. If you can’t sleep during the day after a night shift, it’s important to avoid moving into full daylight if you intend to try and go back to sleep, since light is a strong stimulant for alertness. The Prof introduces ‘Sleep Restriction’ to help increase Sleep Efficiency in Session 3. Most shift workers will already have restricted or short sleep and will be unable to follow the Prof’s advice to adopt a new night-time sleep window. Most people still find it interesting and useful to learn about the concept of sleep restriction, even if they cannot apply the Prof’s recommended schedule.

Core Session 4
Session 4 is particularly useful for shift workers since it explains a number of cognitive and relaxation techniques to help you wind down at the end of a shift.

Core Session 5
Session 5 helps to address troublesome thoughts about sleep. Listen to audio recordings on Paradoxical thinking and Mindfulness as you drift off to sleep.

Core Session 6 and beyond
After Session 6 you become a Graduate of the program. You will have access to a Graduate Common Room discussion, which provides long term support from other users. You can still re-visit the Prof to review your sleep diaries and repeat any aspects of the program in the Library for the full duration of your subscription.

Common questions

Will a nightcap help me sleep?

Alcohol can act as a sedative in the short term but it actually interferes with restorative sleep making you more likely to wake up feeling unrefreshed.

How can I find time to sleep and spend time with my family?

It can be very hard to ‘ration’ social time when you’re working at odds with other people’s social lives. Over time, sleep deprivation leads to irritability and lack of concentration, as well as more serious health risks. You may need to find a compromise between spending time with your family, and finding quality (well-rested) time with your family. Discuss the challenge as a family, and/or with your partner, and find pockets of time that you can protect to be together.

What about melatonin?

Melatonin is a natural hormone which helps regulate the daily sleep-wake cycles to initiate sleep, so scientists have proposed that it could help shift workers to adapt to new shifts.
A review by Costello and colleagues (2014) looked at the results of 8 trials which had investigated the effects of melatonin in shift workers. The results of the six highest quality studies were inconclusive, suggesting that melatonin was not significantly more effective than a placebo (inactive pill).

What about other stimulants?

If you consult a sleep medicine specialist about Shift Work Disorder they may prescribe a wakefulness promoting agent to take before the start of a shift, or before a drive home such as Modafinil. Stimulants are not a replacement for sleep and should only be taken with medical advice.

The science bit

The biology of getting to sleep

Two major biological processes regulate when we sleep:

1. Our circadian rhythm, or daily sleep-wake cycle: this is our in-built tendency for bodily functions to follow a 24-hour cycle. The timing is co-ordinated by the ‘body clock’, an area of the brain which uses external cues like light and temperature to keep us alert and active during the day, and resting or sleeping at night.

2. Our sleep drive, also called sleep-wake homeostasis: quite simply, the longer we’re awake for, the greater our need for sleep.

The circadian rhythm is usually the strongest factor determining when we sleep, which is why we usually get weary at night time, even if we’ve had a lie in.

The brain produces two main hormones which control the circadian rhythm. Cortisol surges in the morning and helps get us out of bed. Melatonin helps us switch off at night. Melatonin usually starts to be produced at around 8-9pm, peaks at 2-3am (when we get super sleepy) and stops at around 7-8am. We typically also feel sleepy at 2-3pm in the afternoon, when there is a natural lull in our alertness.

Natural levels of alertness through the day

Trying to sleep at the wrong phase of the daily cycle means that even if you’ve been working all through the night and built up a strong sleep drive, you could be trying to close your eyes just as cortisol is sending a biological wake-up call. Shift workers often become anxious about getting to sleep which can lead to insomnia.

Safety risks: lulls in concentration and performance

Studies have shown that sleepiness increases across the night shift. Several studies have shown that the odds of sleep related accidents are at least twice as high for shift workers. In one US study, 1 in 4 police officers admitted falling asleep at the wheel while driving at work.

Shift workers are often deprived of the deep sleep required for memory consolidation and learning. The persistent sleep debt associated with shift work has been likened to the reduced attention and concentration of being intoxicated by alcohol. Alertness is particularly impaired during the transition to night shifts

Long term health risks: a system under stress

It’s not just sleep that follows a 24-hour cycle. Our appetite control, growth and repair, metabolic and circulatory systems all anticipate rest and recovery at night, and alertness during the day.

There is evidence that when we eat during the night, for example, it places more stress on our food processing systems, and we are more likely to develop symptoms of diabetes and weight gain. Shift workers are at greater risk of gastrointestinal problems like diarrhea, constipation and ulcers.

Although some people adapt well to shift work, research shows that in the long term, working night or rotating shifts is associated with increased risks of obesity, high blood pressure, heart attacks, breast cancer and prostate cancer.

Antisocial working hours and sleep deprivation can also take their toll on emotional health. Shift work is associated with daytime fatigue, stress, depression, anxiety and relationship difficulties.

References

American Academy of Sleep Medicine (AASM) International Classification of Sleep Disorders Diagnostic Manual (2014), Third Edition

Costello et al. (2014) The effectiveness of melatonin for promoting healthy sleep: a rapid evidence assessment of the literature Nutrition Journal, 13:106

Culpepper, Drake, Schwartz and Thorpy (2010) Shift-work Journal of Family Practice Supplement January;59(1):S3-S31.

Di Milia et al. (2013) Shift Work Disorder in a random population sample – prevalence and comorbidities Plos One 8(1):e55306

Fischer et al. (2016) A unique, fast-forwards rotating schedule with 12-h long shifts prevents chronic sleep debt Chronobiology International 33(1), 98–107

Schwartz & Roth (2006) Shift work sleep disorder: burden of illness and approaches to management Drugs 66(18):2357-70

Steel (2011) Changes in shift work patterns over the last ten years (1999 to 2009) Health and Safety Executive Research Paper RR887