What is Core Sleep & How Much Do You Need?

There’s a chance you’ve heard about “core sleep”, but many of us are unsure what it actually refers to. As it’s not an officially recognised sleep state, information about core sleep can be confusing. Rather than being a distinct stage of sleep, “core sleep” is a consumer term often used by sleep trackers to describe the most restorative portions of your night’s rest. These restorative periods are when much of your physical and mental recovery takes place, making sleep quality and continuity especially important.

We’ve pulled back the covers on everything you need to know about core sleep, including why it’s important and how to maximise it for a better night’s rest.

Core sleep is a non-clinical term used to describe the most restorative parts of sleep. Essential for physical and mental recovery, these restorative periods primarily overlap with deep sleep (also known as non-REM stage N3) and REM sleep. Because “core sleep” isn’t a medically defined stage, its timing and duration vary between individuals and across different sleep-tracking devices, but these phases are crucial for consolidating memories, repairing muscles, and strengthening the immune system.

So what does core sleep do? During core sleep, your body and mind get the most restorative work done. Muscles recover, cells regenerate, and your immune system gets a boost, while your brain processes the day’s experiences and consolidates memories. Hormones that regulate energy, appetite and stress are balanced, helping you feel alert and focused the next day.

Essentially, core sleep is when your body does the heavy lifting behind the scenes, repairing, restoring and recharging, so you wake up ready to take on the day.

So, what is the difference between core sleep and deep sleep? While these terms are closely related, they actually refer to different aspects of the sleep cycle. Deep sleep is specifically non-REM stage N3 and focuses primarily on physical restoration, tissue repair, and immune support.

Core sleep, on the other hand, is a broad, non-scientific term often used to describe periods that include both deep sleep (N3) and REM sleep, which together support physical repair, memory consolidation, and emotional regulation.

Core sleep is vital for physical restoration, including:

• Cellular repair and growth
• Memory consolidation
• Immune system function
• Replenishment of energy levels
• Hormone regulation

Research indicates that the sleep stages often labelled as “core sleep” play a crucial role in maintaining both physical and mental health. Because your slumber plays such a vital role in your overall well-being, you should ensure you’re getting enough each night (we’ll share how later on in this article). 

The amount of core sleep you need is tied to the total amount of sleep you aim to get each night. It’s recommended to get about 7-9 hours of sleep per night, focusing on sleep consistency and minimising interruptions rather than aiming for a specific amount of “core sleep.”

Ultimately, if you get enough rest at night, you will achieve the optimal amount of core sleep, allowing you to feel rested and rejuvenated in the morning. If you wake up during the night, your sleep cycle is likely to be interrupted, resulting in a decrease in the amount of core sleep. To help, we’ve got some tips to get you back to sleep in the middle of the night.

While there are many reasons for these symptoms, they may indicate that you’re not getting enough quality sleep. Try to rule this out by going to bed slightly earlier and minimising interruptions, but if problems persist, speak to a healthcare professional.

If you’re feeling like you’re not getting enough rest at night, or specifically not hitting core sleep during your cycle, it may be down to a few things:

• Sleep deprivation: Not getting enough total sleep, leading to sleep debt.
• Sleep disorders: For example, sleep apnea and insomnia.
• Poor environment: Being too hot, too cold, or too noisy.
• Lifestyle: Including stress, anxious thoughts, or consumption of stimulants.
• Age: Older adults naturally experience less deep sleep and may need to adjust their sleep routines to increase core sleep.

1. Maintain a consistent schedule: Keeping to a schedule will help regulate your circadian rhythm, making it easier for you to fall asleep at night and wake up feeling refreshed. Make sure to get up and go to sleep at the same time every day. Use our Sleep Calculator to help you find the perfect timings.
2. Be mindful of your diet: Going to bed on a full stomach or drinking caffeine or alcohol can disrupt your sleep. Avoid large meals and stimulating drinks an hour before bed, and stick to foods and drinks that encourage sleep, such as chamomile tea and turkey.
3. Wind down before bed: Get yourself calm and ready for sleep by incorporating a bedtime routine filled with relaxation techniques like reading a book or taking a bath.
4. Limit daytime naps: Napping too late in the day or for too long can negatively affect your sleep. Limit cat naps to earlier in the day to improve your rest at night.
5. Optimise your sleep environment: Keep your bedroom cool, dark, and quiet to promote sleep and create a calming atmosphere. Make sure your bed is comfortable and minimise disruptions in your environment to make it easier to fall and stay asleep.
6. Practise good sleep hygiene – Establishing good sleep hygiene helps regulate your circadian rhythm. Limit screen time before bed, prioritise daylight and reduce stress to encourage restorative core sleep.

Getting enough restorative sleep during the night, including deep and REM sleep, is important for your body to repair itself and for feeling refreshed the next day. If you’re waking up feeling unrefreshed, small, consistent changes to your sleep habits can have a big impact over time. For more support, check out our article on how to sleep better at night.