Key Points
- Deep sleep is the slow-wave stage of non-REM sleep.
- Deep sleep is the most restorative stage of sleep, crucial to health and wellbeing.
- You can’t force sleep, but you can take steps to enhance the quality of your slumber.
Sleep is more than just a way to feel rested – it’s essential for our overall health and wellbeing. Although sleep is made up of various stages, it’s deep sleep where the magic and heavy lifting happen. But what exactly is it, in biological terms? And how much deep sleep do we need each night?
This article takes a closer look at the importance of deep sleep and how it contributes to crucial functions within our bodies and minds. So, if you’re tired of feeling tired, read on.
What is deep sleep?
Deep sleep is the third stage of non-REM sleep, where our brains shift into the slowest and most restorative gear. This sleep stage is often called ‘slow-wave sleep’ because the brain produces delta waves – the slowest measurable brain waves seen on deep sleep electroencephalogram (EEG) recordings and often heard in deep sleep music.
CEO of the Sleep Health Foundation and healthylife Advisory Board member Dr Moira Junge, a registered practising Health Psychologist, shares her thoughts about the importance of deep sleep.
“The lighter stage of REM sleep is linked to emotions, memories and learning, whereas deep sleep is associated with physical rejuvenation, muscle recovery, the secretion of growth hormones and immune system reinforcement, as well as having benefits for the brain such as learning and memories.”
When exploring the importance of deep sleep, it helps to think of it as the ultimate reset button for your body – a crucial stage of sleep that allows your body to perform essential repair and maintenance functions.
Lack of deep sleep may impact us both physically and mentally
What happens if you don’t get enough deep sleep?
As humans, we need both REM sleep and deeper, non-REM sleep to survive.
While we’re still learning about the effects of sleep, we know that not getting enough of the deepest kind can have an impact on:
- immune system function
- growth hormone regulation
- building and repair of tissue, bone and muscles
- regulating glucose metabolism
- emotional regulation
- brain detoxification
Ever tried to complete a mentally heavy task after a poor sleep? There’s a reason it can feel so challenging. Research suggests a strong link between sleep and your brain’s neuroplasticity, which can affect how it functions, learns and performs.
How much deep sleep do you need by age?
When it comes to how much deep sleep we need at each age, the data is focused on how much overall sleep we need – because each sleep stage matters – rather than deep sleep specifically.
“You don’t have any control over how much time you spend in each sleep state,” says Dr Moira. “Aim for more sleep in general, and let your brain sort out the rest.”
Healthy sleep cycles include both REM and non-REM (deep) sleep, with deep sleep accounting for approximately 13 to 23% of the total sleep time.
During a typical night, we shift through four to six cycles of REM and non-REM sleep, each serving different functions that are important for our overall health and wellbeing.
Sleep needs vary from person to person and are influenced by many factors, including age, genetics and lifestyle.
As a general guide, the Sleep Health Foundation recommends:
• Older adults (65+) need 7 to 8 hours
• Adults (18–64) need 7 to 9 hours
• Teenagers (14–17) need 8 to 10 hours
• Children (6–13) need 9 to 11 hours
• Preschoolers (3–5) need 10 to 13 hours
• Toddlers (1–2) need 11 to 14 hours
• Infants (4–11 months) need 12 to 15 hours
• Newborns (0 to 3 months) need 14 to 17 hours
Is oversleeping a thing?
Sleep is good for us, so isn’t it a case of the more, the better? Not necessarily. Oversleeping (sleeping longer than 11-12 hours) can leave you feeling excessively tired the next day.
“Yes, we can oversleep, particularly when paying back a sleep debt,” says Dr Moira. “You might wake up at 5am feeling sleep deprived, so you nod off again only to wake up and think you feel worse than before. By starting the sleep cycle again, you might inadvertently wake yourself out of a deep sleep, which is not natural.”
Spending 30 minutes relaxing before bed may help support a deeper sleep
How can I improve my deep sleep?
Although you can’t control how much deep sleep you get – your brain is in charge of that – there are steps you can take to create healthier sleep habits and improve the overall quantity and quality of your slumber. This will naturally lead to improved deep sleep.
Practise good sleep hygiene
While it sounds like ‘sleep hygiene’ it has nothing to do with changing the sheets and banning snacks in bed, practising good sleep hygiene is actually about optimising your habits and environment to sleep well each night.
- Follow a consistent sleep schedule to help your body get into a rhythm.
- Incorporate 30 minutes of wind-down time into your pre-bed routine.
- Optimise your sleep environment with comfortable bedding, low lighting and minimal noise.
- Reduce stimulants like coffee that block sleep-promoting chemicals.
- Nurture your circadian rhythm with sunlight and exercise.
- Create a technology-free zone in your bedroom by removing screens.
Follow the 5 principles of good sleep health
The five principles of good sleep health are designed to help people self-manage their sleep quality and sleep-related challenges.
These principles, designed by a professor of Sleep Medicine at Oxford University, are founded on scientific research and the idea that we can enjoy better sleep if we value, prioritise, personalise, trust and protect it. Find out how.
Focus on creating healthier sleep habits and deep sleep will naturally follow
Here’s the takeaway
Deep sleep is crucial for our health and wellbeing, but it’s just one part of the sleep-quality picture. If you’re consistently waking up on the wrong side of the bed, here’s something to keep in mind.
Deep sleep occurs naturally during healthy sleep cycles, driven by many factors, including our daily habits, routines and lifestyle choices. Rather than worrying about how much deep sleep you need, focus on doing what you can to create healthier sleep habits.
Related:
Dr Moira Junge, a healthylife Advisory Board member, is a registered practising Health Psychologist with the added specialty of sleep. She has been in private practice for over 20 years and is the CEO of the Sleep Health Foundation and was a founding member of the Behavioural Management of Sleep Disorders Committee within the Australasian Sleep Association (ASA). Dr Moira was also Chair of the ASA Insomnia and Sleep Health Council (2008-2015) and is a full member of the Australian Psychological Society.
Reviewed by the healthylife Advisory Board March 2023.
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