Deep sleep is so important for our physical and mental health – here’s how to bank more.
Deep sleep, also known as delta sleep or slow-wave sleep, is one type of non-REM sleep. Brain waves slow down, and the body recovers from the day’s activities – injuries heal, human growth hormone is released, and toxins are cleared from the cerebrospinal fluid. The average adult needs 7-9 hours of sleep and spends 10-15% of it in deep sleep.
If your quality of sleep has plummeted in recent years, it could be playing havoc with your physical and mental health. Sleep is incredibly important for overall wellbeing and directly affects the way the body works, from impacting hormones and metabolism, to hear, circulatory, respiratory, and immune systems.
What makes things trickier is people might think they’re getting a decent amount of sleep at night, but is it good quality enough to be restorative? Here, we break down the importance of banking enough deep sleep and explain why this particular stage is so vital.
What is deep sleep?
Deep sleep, which is also referred to as slow-wave sleep or delta sleep, is the third stage of the sleep cycle. It is a highly active process, despite the fact people snoozing have no clue of its arrival and occurs during the non-rapid eye moment (NREM) block. It follows stage one – those drowsy moments before you drift off, and stage two – light sleep, which makes up around half of your total sleep.
On an average night, a person goes through 4-6 cycles which last around 90-minutes each.
Explaining the third stage in more detail, the Sleep Foundation says “during deep sleep, electrical activity in the brain appears in long, slow waves called delta waves. These waves have a frequency of 0.5 to 2 Hertz and they must make up at least 6 seconds of a 30-second window for that period to be considered deep sleep.”
For most people, this regenerative stage happens in the first hour or two of the night, then occurs in shorter periods until morning. It’s when your breathing and heart rate are very slow and your muscles are super-relaxed, making it incredibly hard to be woken up. In fact, if you’ve even been rudely awakened and experience a groggy sensation for some time afterwards, it’s probably because you were enjoying a nice slice of slow-wave.
Why is deep sleep so important?
Although all the stages of the sleep cycle are important, deep sleep is arguably the most crucial. The NHS describes it as “the most restorative sleep stage” but explains that “all sleep stages play a vital role in keeping us healthy and functioning at our best”.
Getting enough deep sleep means improved immunity, memory, and muscle growth, as well as better heart, tissue, and bone health, says the Sleep Foundation. It helps to boost cognitive function and memory, making it particularly vital for developing brains, alongside regulating glucose metabolism and replenishing energy stores.
Studies have also shown this stage plays an integral role in allowing the brain to process the day’s overload – that’s before we’ve even mentioned the mood-boosting benefits.
Deep sleep is the deepest stage of NREM sleep (non-rapid eye movement) – brain activity slows down and muscles relax during deep sleep. During deep sleep, the stress hormone cortisol decreases. Deep sleep also boosts the immune system by producing proteins called cytokines, which fight off infections and diseases. If you don’t experience deep sleep consistently, you have a higher risk of developing health conditions, including heart disease and Alzheimer’s.
How to get more deep sleep
Sleep health is a hot topic as many people struggle to fall asleep – or stay asleep. The impact of a bad night is bad enough, but consistently bad sleep can become a mental and physical health nightmare.
So, how can you bump up the amount of restorative deep sleep that’s so beneficial to our bodies?
“The best way to get more deep sleep is to get enough total hours of sleep,” explains the Sleep Foundation, adding: “Most deep sleep happens in the first hour or two of sleep. As a result, sleep habits that help people fall asleep faster may also help them to get more deep sleep naturally.”
Reams of studies have been conducted over the years to discover how people can improve their bedtime routine, which sparks sleepiness more quickly.
Here are just a few suggestions:
Go to bed at the same time every night
According to the Sleep Foundation, an inconsistent sleep-wake schedule affects people’s circadian rhythms. A wake time establishes a pattern and helps your circadian system to be regular and robust which helps your sleep quality. Going to bed at around the same time in the evenings will become easier to do once you’ve established a regular rise time.
Minimise your stress
Stress and anxiety can impact the amount of deep sleep you manage so try some calming activities like breath work or yoga before bed.
Ditch the caffeine and alcohol
Booze and coffee are stimulants, so why not switch them out for soft drinks like herbal or decaf tea.
Create the perfect sleep environment
Loud noises and bright lights are a no-go so alter your space to include a dark, quiet, cool bedroom with some comfortable bedding. A dark room encourages melatonin production, a circadian hormone that tells the brain it is time to sleep at night.
Choose breathable bedding
Bedding and pyjamas made from cotton and bamboo ensures you sleep cool. These materials are more breathable than fabrics like polyester or microfiber.
Develop a bedtime routine
Taking a hot bath or shower and reading a book every night helps your mind associate these activities with bedtime. Similarly, what you cut out before bed can also contribute to your bedtime routine. We already mentioned turning off your devices, and you should try to avoid eating before bed too.
Turn off electronic devices
Limiting screen time at night and turning off your mobile phone or tablet before bedtime gives you a chance to relax before falling asleep. Too much blue light exposure can disrupt melatonin production, a hormone that helps to regulate the circadian sleep-wake rhythm and tells the brain that it is time for sleep at night.