Deep sleep is the most important stage of sleep that we go through each night and is vital for our bodies to rest and recuperate.
Humans typically experience two types of sleep. These are known as REM (Rapid Eye Movement) and Non-REM. Deep sleep occurs under the final stages of the Non-REM cycle. This is after we’ve fallen asleep and the body has started to relax.
Not getting enough deep sleep can affect the body, leaving us over tired and struggling to wake up the next morning. So it’s worth noting how much we need and how we can improve how much we get over time.
Here, leading sleep experts share their knowledge and top tips on how to achieve more deep sleep each night.
What is Deep Sleep?
Deep Sleep is a period of sleep that takes place before dreaming. It is called deep sleep as this is when we are least likely to wake up and are often enjoying our deepest slumber.
“Deep Sleep is a stage of sleep that we move into after about 20-25 minutes of falling asleep and it is very important to our physical recovery,” says James Wilson, a sleep behaviour and environment expert known as The Sleep Geek.
“It is when growth hormone is released and where our organs, muscles and cells repair,” adds James. “And it’s where the process of consolidating memory starts and where our body releases chemicals that support our immune system.”
The restorative process that takes place during deep sleep is often what makes us feel like we’ve had a good night’s rest in the morning.
“Unlike Rapid Eye Movement (REM) sleep, deep sleep is when the brain waves slow down,” says Wayne Ross, a sleep researcher and advisor at InsideBedroom. This type of sleep is also often referred to as Slow Wave Sleep (SWS).
“It is difficult to wake from slow wave sleep, and when we do wake it takes a while to realise or become fully aware of our surroundings and situations.”
How much Deep Sleep do you need?
A quarter of our sleep time equates to deep sleep, so this equates to at least 90 minutes a night. Although generally if you can get more than an hour and a half that would be beneficial.
“Everyone is different when it comes to working out how much deep sleep we need,” says Sleep Geek James. “A good eternal rule is that about 20% of your total sleep time should be made up of deep sleep.”
The NHS recommends adults aim for about 6-9 hours sleep a night and so based on this, James encourages just over 90 minutes of slow wave sleep everyday.
“It is advisable for an adult to get 1 to 3 hours of deep sleep per 8 hours of nightly sleep each night,” he tells us. This amount is key to feeling rested, staying healthy and waking up happy.
Research suggests that getting the right amount of slow wave sleep could help fight-off brain diseases like Alzheimer’s. One study showed that high levels of cerebrospinal fluid (CSF) was detected during deep sleep. And this flushes out toxins, helping your brain stay healthy. Whilst another study revealed that slow wave sleep decreases in old age so it’s wise to take steps to improve the quality you have as soon as you can.
How to increase your amount of deep sleep
There are a number of bad bedtime habits which can affect our quality of kip. These should be addressed when wanting to increase your amount of deep sleep.
“There is some research to show napping can worsen the quality of slow wave sleep,” says James. “And eating too close to bedtime raises our core temperature and can impact on the quality of our sleep
“Winding down properly before bed, focusing on activities that drop our heart rate and allows us to relax helps. As does having a warm bath or shower to drop our core temperature and make us cooler,” he adds.
Expert Wayne agrees that a warm bath will set you up for a better snooze too. He also suggests avoiding stodgy foods before sleep and a low-carbohydrate diet. One study showed that the low-carb Keto diet increased slow wave sleep in participants monitored.
Further research has revealed that exercise plays a part in increased sleep quality too. One study showed that exercising in the evening improved slow wave sleep. And another study found the same results when the majority of people exercised after 8pm.
Wayne adds that sometimes the best thing you can do is not overthink it: “It is known that the more you force yourself to sleep, the poorer the sleep quality upon awakening. Just sleep when you can.”