Man light sleeping

Why do we need light sleep?

09 Dec 2022


Are you a light sleeper or a deep sleeper? Or maybe you’re a bit of both?

We focused on deep sleep in this article, so now it’s time to focus on light sleep. But first, let’s spend a few minutes exploring the wonderful world of sleep…

What is sleep?

We all do it, but how many of us actually think about what it is? What happens when we sleep? How does it happen? Now, for the science bit…

Our bodies and brain are complex things, which are controlled by nerve-signalling chemicals called neurotransmitters, among many other things.

It’s these neurotransmitters that are responsible for reducing our levels of serotonin and norepinephrine, which are two of the things that keep us active and awake. When these neurons switch off, we get sleepy, also because the amount of adenosine we have pumping around in our blood drops. This can also make us feel drowsy.1

Why do we need it?

Sleep is part and parcel of everyday life. But have you stopped to take a minute to think about why we actually need it?

There’s such a vast amount of information about sleep out there and what it does to the human body. But, in a nutshell, sleeping helps us make sense of our memories. While we’re sleeping, our brain processes our experiences and files them away, from our short to our long-term memory.

Meanwhile, sleep is the time when our bodies and brain recharge and repair. It’s precisely why growing babies and children need much more sleep than adults, to help fuel the growth and development that’s happening physically and mentally.2

How much sleep do we need?

Our recommended sleep quota depends on how old we are. Basically, the older we are, the less sleep we tend to need.

Most adults need 6 to 9 hours of sleep every night and children need anything from between 16.5 hours a day (1 week old baby) to 9 hours a night (16-year-old).3

What is light sleep?

It is, as the name suggests, light sleep, and it tends to happen as we go from being awake to falling asleep. It’s estimated that we spend about half of our total sleep time in a light slumber. When we’re light sleeping, our heart and breathing rates slow down and we do actually dream, but they’re not on the same level as REM dreams (more on REM below). We’re still sensitive to noise, temperature, touch and movement and it’s easier to wake up. In fact, if you do happen to get woken up during light sleep, you may feel as though you’ve not slept at all.4

Where does light sleep fit in the overall sleep cycle?

You may, or may not, know this, but our sleep happens in phases and there are essentially five of these phases.5

  • Stage 1: Light sleep – when we’re awake and just starting to go to sleep.

  • Stage 2: The onset of sleep – when our body relaxes some more and our body temperature drops.

  • Stages 3 & 4: This is when the deepest and most restorative sleep happens. (Stage 4 is known as the ‘healing phase’ because it’s when tissue growth and repair takes place, hormones are released and energy’s restored).6

  • REM (Rapid Eye Movement): This is when we dream and important mood, dream and memory-related functions happen. REM sleep takes place around 90 minutes after falling asleep and again every 90 minutes, getting longer later in the night.7

How much light sleep do you need?

On average, light sleep takes up between 50 and 60% of our daily sleeping cycle. It’s classed as being the leftover time that you spent not being in deep or REM sleep. Either way, it’s still a form of sleep.

As for light versus deep sleep, deep sleep takes up between 10 to 25% of your sleep, depending on your age. Interestingly, it’s not possible to have too much deep sleep because your body will switch to REM or light sleep mode once it knows you’ve had enough deeper ZZZs.8

Tips for getting more light sleep

You can’t prescribe exactly how much of the different stages of sleep you’re going to get every night, but you can do certain things to help improve your quality and quantity of sleep. Tips include:

  • Having a hot bath – which warms you up. Heat can potentially promote more slow wave sleep
  • Establishing a bedtime routine
  • Steering clear of caffeine before bed (read ‘Why your diet is stopping you sleeping.’)
  • Regularly exercising
  • Relaxing at bedtime – e.g. by reading a book or listening to chilled music
  • Making your bedroom sleep-friendly - remove any bright lights or distractions (devices, TVs etc.)
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Last updated: 18 September 2020

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