Why we sleep

We all talk about ‘going to sleep’ without really thinking much about what it means.

It may seem like a waste of time in our 24/7 world but sleep is not a luxury – it is a biological necessity. All animals have a sleep-wake cycle, from tiny fruit flies to humans.

In humans, sleep is vital for good physical and mental health. We need to sleep for normal mood, memory and metabolism. Sleep is also needed for growth, for the immune system and to maintain the right body temperature.

Bad sleep for any reason affects brain function. If you sleep badly you feel grumpy and irritable, a little more impulsive and attention and concentration is worse. It is also harder to learn new things – memory processing and new learning happens during sleep.

So, a good night’s sleep is vital for the body and brain to work at their best during the day.

We don’t really remember much about the night when we sleep well but we now know that distinct areas within the brain control a complex and very active process that changes over the night.

If we think of the brain as different electrical circuits then two separate circuits control how long we sleep (the hours) and when we sleep (the body clock – we are designed to sleep best at night when it is dark).

We need more sleep when young and when we are ill but a little less as we get older. Body clocks do change – with teenagers happy as night owls but most of us falling asleep earlier as we get older.

In the Trust’s sleep clinic, we can record sleep and look at brain activity (the EEG) and see that there are two main stages of sleep – dream sleep (also called REM sleep) and non-dream sleep (NREM).

We cycle between the different stages about every 90 minutes as adults. We all wake at night although we may not remember this and we all dream a little more in the second half of the night.

Hypnogram of normal sleep

A graph of hyponormal sleep

Find out more about the science of sleep
with these great TED talks

Why do we sleep? – Russell Foster

Sleep is your superpower – Matthew Walker

Getting the best out of your shifts

Many of us work shifts. We need to! Hospitals aren’t only open from 9am to 5pm – we’re a 24/7 service and our patients need care both day and night.

That’s why it is really important to make sure you – and your patients – are getting the best night’s sleep that you can. A rested health professional is a better health professional!

Sleep is flexible, when normal sleepers are studied, they sleep different amounts of time on different nights of the week. But it is worth adding up the total number of hours in an average week…

Is it 40, 45 or 50? For most adults – sleeping under six hours a night on a regular basis will make them feel tired – how do you feel when you wake up in the morning?

If you wake up feeling fine and refreshed – then you are probably getting things right and having enough sleep. Different people need different amounts of sleep. Shift work does make us sleep at the wrong times for our body clock and can cause us to get too few hours in bed.

One phrase sleep researchers have used recently is ‘social jet lag’ – the idea of sleeping a lot longer on your free days compared to your work days.

This can be a sign that you are running a little short of sleep on your work nights. Making sure there is enough of a gap between one shift and the next is important, at least 11 hours if at all possible.

This might mean you don’t arrange too many things to do on your days off so that you do get a chance to catch up and you plan ahead for your shifts to protect your sleep as much as possible.

There are some useful tips for shift work in the links below if you need more information and ideas.

There are also some really good tips to fight fatigue during the shift from the Association of Anaesthetists – you may have seen their leaflets around the hospital?

Download your ‘Working well at night’ poster

Wide awake at the wheel?

Driving after a night shift can be a risky time and many people find a different way to get home to avoid a long drive.

We can start to have ‘microsleeps’ – these are fleeting, uncontrollable episodes of sleep lasting a fraction of a second up to ten seconds, seen when a sleepy person is trying to remain awake. Some people recognise the ‘nodding dog’ as their head drops forward.

Things like turning on the cold air in the car, chewing gum or playing music are things people often do when they are feeling tired to keep awake. This may seem like a good plan but needing to do this in the first place is another warning sign of sleepiness. It may be better to pull over.

Hitting the rumble strip, or a near miss on a recent journey, are other warning signs for sleepy drivers. Make sure you and your work colleagues all get home safely.

Driving while critically tired is illegal and people have lost their licences because of this.

Driving after being awake 20 hours is an equivalent effect of driving over the legal alcohol limit, which we would not do.

We often get a sense of relief from completing our shift and handing over patient care.

For the first few minutes at the wheel we might feel fine but long drives should be avoided if at all possible after a long night, particularly those over an hour. There are some warning signs when we are getting sleepy behind the wheel.

You may also find this ‘Safe to Drive’ poster useful

Top Tips for a peaceful night


Put phone, tablet and screen devices away – yes that includes a whale song! Those pop ups you say you never look at, the last minute email… We all enjoy the Chief Executive’s blog but read it during the day.


Night follows day – what you do during the day makes a big difference to the night. Being outdoors in natural light every day and out of breath exercise are really good for sleep, not just daytime energy levels. Any kind of high intensity exercise deepens sleep.


Coffee – we are all different but if you don’t fall asleep easily or wake a lot, count the cups. Cut down if you have more than three to four a day and don’t drink it after lunch!

Where to get help if you need it?

If you are struggling to stay awake – or fall asleep – and you feel it is causing you problems, there is lots of help available and often some simple things you can do to work out what the problem is.

We have included some useful resources below to all sorts of sleep problems.

These should help you determine things you can do to improve your own sleep and some which may need help from GP or occupational health. We have also included some new sleep groups that you might find useful to join.

Need more support

Starting on Monday 2 September, we will also be providing psychoeducation support for sleep issues at Regent Point (11am to midday).

To access this support please speak to your line manager and a referral will be made to newcastle.ohs@nhs.net