Written by Dr Sara McNeillis and Dr Hugh Selsick. Edited by Emma Grindrod and Alencia Trim.
Sleep is governed by two processes. One is our internal body clock, and the other is sleep pressure, which is proportional to the number of hours we are awake. Shift-work often disrupts both processes. The following guide will help you maximise your ability to sleep whilst juggling shift work.
In the red
We all build up a sleep debt on any day where we don’t get the amount of sleep we need. We allcarry over some sleep debt. Often, we try to repay this by sleeping extra hours (commonly “lie-in”) at the weekends. Shift work can be regular or sometimes there are last-minute night shifts asked of you. It’s definitely best to avoid repaying sleep debt in a random way – this won’t always make up the debt, and once the debt has been cleared we do not benefit from additional sleep. We need to plan for optimal sleep stability.
A few things to remember
Our circadian rhythm informs us when we are hungry and when we should sleep. It ensures we are sleepy between 2am and 4am in the night, and maybe a bit tired between 1pm to 4pm in the afternoon. Our circadian rhythm is kept in time by light and melatonin release.
- Light has a maximum effect in the morning and late evening
Sleep onset is best when the body temperature is falling rather than rising. - Having a bath is helpful because it means your body temperature rises and then falls again
- Also, if you’re too warm while asleep, there is a possibility of reducing REM or dream state sleep, which helps with memory
Before a night shift
Having a normal day, i.e. being awake during the day before a night shift, can cause an increase in the risk of accidents. You can minimise this risk by increasing your sleep time in the days leading up to a night shift so that you are not starting with a heavy sleep debt.
During the day:
- Try to have a “lie-in” in the morning
- Use eye-masks and light-limiting blinds to reduce light input in the morning
- Try to nap after lunch
- It is important to eat a balanced diet. Regular mealtimes should be maintained. Eat breakfast in
the morning lunch around midday and dinner in the evening. Do not have a large meal before
or during the night shift. - A light meal with less starch-based carbohydrate can help you to maintain wakefulness during
the night shift. - Aim to have a walk outside and get some evening light to delay your sleep onset.
During a night shift
It is important to realise that your circadian rhythm will continue for a few days despite change in sleep schedule. You may feel sleepy in the later half of the night shift.
- Try to take breaks and naps during the shift, if you can.
- Caffeine containing drinks may boost alertness by counteracting the sleep pressure. Aim to have a caffeine drink timed 3hrs before your maximum sleepy period. Often this is around 3-4am
- Bright light (10000 lux) can improve wakefulness. You could use this for 15 mins every hour during the night shift. Some examples: https://bestreviews.com/best-light-therapy-lamps
After a night shift
You may feel extremely sleepy or extremely awake.
- Aim to get 4 hours sleep in the day after a night shift so that you clear some sleep debt but not all.
You may need to travel home and be alert. So, if extremely sleepy:
- Have caffeine intake for the journey home
- On the way home, wear dark glasses to prevent light input
- Ensure the bedroom is well-ventilated and dark
- Put your phone on silent
- On awaking, have a meal and get some evening light to delay the sleep onset for the next night shift.
Similarly, alertness-promoting neurotransmitters may override the sleep onset. It is important to reduce these by using relaxation techniques.
If you’re extremely awake:
- Wear dark glasses after work to minimise light input
- Eat a meal containing starch based carbohydrate
- Avoid caffeine intake 3 hours before planned bedtime
- You may find exercise immediately after a night shift helpful to increase the depth of sleep
Return to normal days
It is important to maintain a steady relationship to sleep debt to help return to normal night time sleep.
- Take a caffeine containing drink at 2pm to reduce the sleep pressure for the early evening
- Exercise in the afternoon
- Wear sunglasses in the early evening to minimise light input
- Have a meal with some starch-based carbohydrate in the evening
SHIFT WORK SLEEP DISORDER
This disorder occurs in up to 26% of shift workers. It may be associated with adverse health and can be treated. It is important to recognise the condition and seek help via referral to a sleep specialist. Shift work sleep disorder occurs despite a good opportunity to sleep and can result in either excessive sleepiness in the night shift or insomnia following a night shift. If you think this is happening for you, refer to the sleep clinic by contacting Dr Sara on venkata.mcneillis@nhs.net
