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The stages of sleep

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Experts recommend getting between seven and nine hours of sleep a night to wake up feeling well rested, but those hours won’t all be spent enjoying the same type of sleep . Far from it. Find out why, what the different sleep stages are and how to make the most of them.

Sleep basics

On a good night, you might get into bed, fall fast asleep and, as far as you’re concerned, stay that way until your morning alarm sounds, right? 

But don’t be fooled – there’s much more going on in your brain throughout a sound night’s sleep than you might think. In fact, sleep is anything but ‘uniform ’. 

The first thing to know is that sleep occurs in cycles and you experience four, five or six sleep cycles every night. 

A single cycle contains four different sleep stages, and the length of each cycle, as well as how long you’ll spend in each sleep stage, tends to vary throughout the night. 

Roughly speaking, each sleep cycle lasts between 70 and 120 minutes, and the first cycle of the night is usually the shortest .

Get to know the stages of sleep

There are four stages of sleep – three non-rapid eye movement (REM) stages and one REM stage. Typically, a sleep cycle begins with Stage 1 sleep and ends with Stage 4.

Stage 1

This is when you’re just dozing off. It usually only lasts for a few minutes and is a very light type of sleep that you can be easily woken from if things aren’t quiet or you’re disturbed.

While your body doesn’t fully relax during this stage, brain activities start to slow, often with periods of brief movements, which present as those ‘twitches’ you might experience sometimes as you’re falling asleep . 

Stage 2

In this stage, your muscles relax, your breathing and heart rate slows and your temperature falls. Brain activity also slows. In the first sleep cycle of a night, Stage 2 lasts for 10-25 minutes, becoming gradually longer in each subsequent sleep cycle.

Over the course of a night, you’ll spend about 50 per cent of your sleep time in this stage .

Stage 3

Also known as slow-wave sleep, Stage 3 is the deep, restorative sleep that’s thought to be most essential for maintaining good health and for supporting brain-related tasks such as memory and creativity.

During your first few sleep cycles, stage 3 lasts for 20-40 minutes but then gets shorter and shorter in later sleep cycles . 

Stage 4

Also called REM sleep, as the name suggests, it’s during this stage that your eyes move rapidly behind closed eyelids thanks to your brain’s activity picking up significantly. 

A type of sleep that’s also important for cognitive functions like memory, learning and creativity, you’ll have your most vivid dreams during REM sleep, even though dreams can – and do – occur during any sleep stage. 

Thankfully, another feature of REM sleep is that your arm and leg muscles become temporarily paralysed, which prevents you from acting out those vivid dreams. 

In early sleep cycles, REM sleep usually only lasts for a few minutes, but in later cycles, it can last up to an hour. REM sleep makes up about 25 per cent of your total sleep time .  

What sleep stage matters the most?

While every sleep stage is slightly different, they’re all important, not only because they act as transition phases from one stage to the next, but because they allow your brain and body to develop, repair and recuperate. 

That said, it’s a lack of stage 3 and REM sleep that’s thought to trigger the impact that not getting enough sleep can have on your health and wellbeing . 

Can you improve your sleep cycles?

Sleep cycles can be affected both by things that aren’t within your control and things that are. For example, ageing impacts sleep cycles, so you’ll spend less of your night in REM sleep the older you get. On the other hand, drinking alcohol too close to bedtime can disrupt your sleep cycles .

To give yourself the best chance of enjoying a sound, restorative night’s sleep, try:
  • Sticking to the same bed- and wake times. Irregular or insufficient sleep over a few days can lead to abnormal sleep cycles
  • Improving your ‘sleep hygiene. You’ll have made a good start if you get up and go to bed at the same time each day, but there are other healthy habits that contribute to a good night’s sleep, including establishing a relaxing night-time routine and practising sleep meditation
  • Avoiding alcohol in the evening. Otherwise you’ll miss out on REM sleep early in the night and then get too much of it later on
  • Fuelling up on the right foods. While some foods support a good night’s sleep, others can have the opposite effect. Learn how to create a slumber-friendly menu
  • Consider a sleep supplement. These can help to reduce the time it takes to fall asleep as well as promoting a deep, refreshing sleep. Learn more about which one may be right for you
Keen to do more? Commit to our 4-week Restore your sleep Action Plan, where you’ll discover sleep-tight tips and advice for morning, noon and night.