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More sleep! Better sleep! Deeper sleep! It's what we all want, right? In that case, might we introduce you to the concept of ‘core sleep’? If you can nail this fundamental hack to good sleep, then you've got yourself on a one-way train to sleep town.
While some people may find it easy to clock in eight hours of uninterrupted rest each night, others find themselves laying staring at the ceiling late into the night, waking up throughout the night, or waking up still feeling exhausted even after a long sleep.
If you still haven't hacked the whole sleeping thing, it might be worth looking at the individual stages of the sleep cycle to find out where you're going wrong. Arguably, the most important phase to look at is core sleep, which covers the first three stages of the cycle — without core sleep, you won't get the benefits of sleeping at all. So, what is it, why is it so important, and, most importantly, how do we get more of it?
We spoke to GP Dr Anatalia Moore to find out more.
It's about sleeping like a baby – literally.
What is core sleep?
Core sleep refers to the first three phases of the sleep cycle:
- Stage one: The phase where we drift off into dreamland. The in-between phase.
- Stage two: The phase where we disconnect more from the real world and prepare for deep sleep.
- Stage three: Deep sleep. This is where the good stuff starts happening like muscle repair and immune strengthening.
- Stage four: REM sleep. The phase when we dream — and not considered part of “core sleep”.
This cycle repeats several times — ideally four to six times — over the course of one night's sleep.
In other words, core sleep refers to every stage of sleep before we start dreaming. Although sleep experts recommend getting a full night's sleep that cycles through all four stages, the first three stages are thought to be essential for normal functioning throughout the day.
Why is core sleep important?
Deep sleep is an essential part of the sleep cycle — it's when our bodies being to repair from the day. It's the phase that helps you wake up feeling physically rejuvenated as it contributes to alertness, mood, hormone regulation, and healthy immune function. Without core sleep, it can be almost impossible to function as normal the following day.
“As the term core sleep refers to a combination of phases of sleep that happen at the middle and end of sleep cycles, people who find their sleep very interrupted will not be getting the opportunity to reap its healing benefits," warns Moore.
This can mean your body doesn't heal itself. “Denying your body and mind the opportunity to heal can lead to a massive range of physical and mental health issues," she says. “Initially you may notice you look less refreshed, with dark circles, sallow tones and more inflammatory skin conditions being a visible indicator of the lack of time your body has to repair.”
She adds, “If this continues the range of symptoms is phenomenal, ranging from low mood, difficulty concentrating and low libido, to weight gain, diabetes, poor immunity and hormonal issues."
How many hours of core sleep do we need?
In the first cycle, deep sleep is usually shorter — around 10-25 minutes. However, with each cycle, the amount of time we spend in deep sleep gets longer and longer. Over the course of a healthy 7-9 hour sleep, core sleep should account for around 3-4 hours.
Of course, this is just a guideline. “Depending on how long your sleep cycle is, the amount you need to feel refreshed can vary," Moore says. “Initially as you fall asleep you will notice you are likely to potentially wake easier, and as you slip into deeper sleep this lessens and when uninterrupted is the time that your body has opportunity to repair from physical wear and tear of the day. As you then progress into REM sleep your mind has the chance to consolidate memories and sort through mental stresses.”
How to optimise your core sleep?
If you're struggling to get the right amount of core sleep each evening, it's important to make sure your body and mind are optimised for this essential sleep stage. In general, practicing good sleep hygiene is a great way to encourage the body to settle into the core sleep stage.
“All the things that classically set you up for a good night's sleep will give you the best chance of achieving core sleep,” says Moore. “From the moment you wake you should be mindful of how your lifestyle impacts your sleep quality as well as duration.”
This includes avoiding blue light before bed, sleeping in a dark, calming room, eating a healthy diet and digesting before bed time, avoiding caffeine in the evening, and possibly practicing meditation or doing some gentle stretches before getting into bed.
Tracking your core sleep
Sleep trackers are a great way to see if you're getting the right amount of core sleep each night. Over time, you'll be able to track the data to see patterns — is your core sleep often interrupted at the same time each night? Are you skipping the REM stage during the evening? Are you falling asleep in the same amount of time each night? Try to compare this data to how you're feeling each morning. Do you feel more energised and rested after a night with more core sleep?
