Exploring the different stages of sleep

Sleep is a huge part of being a human – and most of us spend about a third of our lives asleep.

Many people know that there are two different types of sleep - rapid eye movement (REM) and non-REM.

However, what a lot of people don’t know is that there are actually four different sleep stages that you pass in and out of throughout the night.

How much time you spend in each of these sleep stages, and the stage you wake from, can have a massive impact on how rested you feel and how much energy you have throughout the day.

Here are the 4 stages of the sleep cycle and why they matter...

NREM (non REM sleep) Stage 1

This is the lightest phase of non REM sleep, which first occurs as you're first falling asleep. It can last up to seven minutes and you may be easily woken up during this time.

During this stage of light sleep some people may experience what's known as myoclonic jerks – twitches or startle reactions that occur as certain motor areas of the brain are stimulated.

Your brain will spend most of the night in this stage, taking up around 50 per cent of the time that you're asleep. Each stage 2 sleep cycle lasts up to 20 minutes. Your heart rate and breathing slow down, your body temperature drops and you'll lose awareness of your surroundings.

NREM Sleep Stage 3

This deepest stage of sleep is also called slow wave sleep, because of the slow brain waves that appear on an EEG (electroencephalogram) machine if your brain is hooked up to one. This restorative deep sleep stage lasts for between 20 and 40 minutes and becomes progressively deeper as time goes on. Most of your stage three deep sleep occurs in the first few sleep cycles of the night.

REM sleep

REM sleep is the dreaming phase of sleep.

REM sleep is very active and is actually similar to being awake in many ways. The muscles in your limbs are temporarily paralysed, which is believed to be an adaptive mechanism to prevent you from acting out your dreams and hurting yourself whilst asleep.

You spend around a quarter of your time asleep in REM sleep. An initial REM sleep cycle might only last for five minutes, but REM cycles get longer as the night progresses.

Your brain will go through REM sleep cycles alternating with the NREM stages of sleep all night long, with brief awakenings throughout. This is normal and not something to be worried about - most people don’t even notice they've woken up.

After reaching stage 3 of the sleep cycle, the sleeping brain ascends back to lighter stages of sleep, often stopping for a period in stage 2 on its way back up to REM.

If you're not getting enough sleep, your physical and mental health can suffer

We are all different, but experts in sleep medicine say that anywhere between four and 11 hours per night can be considered normal.

But getting just one hour less sleep a night than you need can have measurable effects on your physical and mental health, and cumulative sleep deprivation can have long-term health consequences.

If you feel yourself falling asleep during the day, then you're most probably not getting the sleep you need during the night.

For those with sleep disorders such as sleep apnea, the deeper levels of sleep in the sleep cycle may not be reached as frequently because they are constantly being woken.

Sleep deprivation can lead to the body being unable to repair damage, few dreams and increased fatigue when waking and throughout the day.

The right mattress is important to help you fall asleep and reach deep sleep

Mattress industry experts and the Sleep Council agree that you should replace your mattress at least every eight years, as it will gradually lose the support and comfort it once offered.

Research shows that sleeping on an old or unsuitable mattress can mean you lose up to an hour’s sleep every night, so it’s important to choose the best mattress for you to ensure that you get a good night of quality sleep.

Do you have trouble falling asleep? Maybe you've been sleeping on the same mattress for too long...

25th January 2022