What is ‘deep sleep’.. and how much do you need per night?

Deep sleep: the absolute gold of all gold when it comes to sleep, the key to feeling rested, refreshed and rejuvenated… before caffeine. Though most of us don’t really remember what this is - a 2023 survey found 4 in 5 Aussies are struggling to fall asleep, and 49% aren’t sleeping enough - sufficient deep sleep will actually make you feel this way. While yes, it is true that any sleep will help you feel better the following morning, not all sleep is the same. To separate fact from fiction, and to help you understand exactly how much you need - and how to know if you’ve gotten enough, read on.

First though.. what happens in deep sleep?

Deep sleep usually refers to stage 3 + 4 NREM (non-rapid eye movement) sleep; also known as slow wave sleep. Stage 3+4 NREM comes first in the evening, and is signified by a few factors: the body is in a deep state of relaxation, heart rate slows, breathing slows, brainwaves slow down too - delta brainwaves predominate - and you are extremely hard to wake.

Is it true that deep sleep is important for physical recovery??

Yes - it’s true: 70% of human growth hormone is produced here, the key catalyst for cellular repair, lean muscle mass development and collagen. It’s also vital for memory and mental clarity - in this stage, our brains encode declarative memories to long term storage, allowing us to remember facts accurately - e.g. someone's name.?

What about REM sleep??

Though REM (rapid eye movement) sleep isn’t typically termed ‘deep sleep’ - it should be: it’s in fact, a deeper stage of sleep than stage 3+4 NREM sleep. REM is also known as ‘dream sleep’., and yes, it is when dreams take place. Unlike NREM sleep, your brain is highly active in this phase - akin to consciousness - with alpha, beta and gamma waves present, and with respects to breathing heart rate and blood pressure, they all increase. Paradoxically though, you are in a deep state of rest, so much so that your muscles lose all tone, and you are physically paralysed - which protects us from acting out our dreams, and any associated harms.?

While physical restoration and memory formation continue to take place during REM sleep, it’s particularly beneficial to our mental health, and is exactly where the term ‘sleep on it - you’ll feel better in the morning!’ comes from.?

Why is REM sleep important for mental health??

As we continue to encode memories into our long term storage; with those memories comes emotions. And, And, as a self preservation mechanism, during REM sleep, we ‘detox’ from negativity, we become more neutral and positive about these experiences. As a result, the next day, we are more likely to feel better about them. Fun fact!

How much deep sleep and REM sleep do we need??

We need to hit the following benchmarks: 25% REM sleep and 20% stage 3+4 ‘deep’ NREM sleep. The only real way to know if you are achieving these margins is by tracking your sleep - wearing devices such as Apple watches, Oura rings and Whoop bands.?

3 top tips to get more deep sleep?

Start with the fundamentals first: track your sleep, track your drinking (alcohol and caffeine especially), and track your food. Tracking your sleep naturally encourages you to make better decisions - no one wants to see they have let their sleep go awry night after night. When it comes to your drinks, note alcohol suppresses REM sleep, and caffeine delays deep sleep, as it suppresses adenosine, a sleep promoting hormone that, like melatonin, helps us fall asleep.?

When it comes to food, again, keeping a food diary encourages healthier decisions, promoting deeper sleep: nutrient dense meals high in quality protein, greens and healthy fats (e.g. green protein smoothie, a salmon poke bowl, chicken and avocado salad) can help us sleep better, as can snacking on magnesium and omega 3 fatty acid rich options, such as a handful of almonds or a chia seed pudding. Understandably though, we have a lot on our minds (especially at this time of the year), which is why tracking our food can support us here - it allows us to see, in plain sight, if we have eaten well to sleep well.. Or not.?

Final thoughts:?

So - now you know: what deep sleep is, how much you need, and how to get more. That said… we are well aware - it is the festive season, and often, everything does go awry at this time of the year. And that’s completely ok. Whether it’s now or later, action this advice and jump on the deep sleep bandwagon - you’ll thank us in the morning.

This article is another instalment of Sleep for Success - a LinkedIn series empowering you to your best nights sleep. With sleep not only important, but imperative for optimal wellbeing and peak performance alike; it's a pleasure to leverage my 14 years of academic and professional experience to share expert tips, tricks and techniques to help you sleep longer, deeper and wake more refreshed. Supercharged by sleep, look forward to achieving more, in less time, with less effort - naturally. Please share with anyone you feel will benefit, and of course, sleep well.