Unlocking the power of deep sleep: how much do you need?

In the hustle and bustle of modern life, sleep can often take a back seat. But did you know that sleep, in particular deep sleep, is crucial for your physical and mental wellbeing? It’s not just about the quantity of sleep you get, but also the quality, when it comes to the protective and rejuvenating effects of deep sleep. In this article, we cover how much deep sleep you need and how to get more deep sleep.

Understanding deep sleep

What is deep sleep? When we sleep, we progress through four sleep stages. Changes in brain and body activity are associated with each stage. Deep sleep, also known as slow-wave sleep or delta sleep, is a stage where the brain experiences profound rest and recovery. Brain waves are long and slow. During this time, the body repairs and grows tissues and muscles, consolidates memories and supports the immune system.

It’s the third phase of the sleep cycle and lasts around 20-40 minutes. Most adults will go through four to six cycles a night, however, sleep patterns and requirements change throughout our lives. Interestingly, most deep sleep occurs earlier in the night.

Research suggests that deep sleep is neuroprotective. It may help recovery from strokes and even shows promise at helping those diagnosed with Alzheimer’s disease, although these interventions are in their early stages of development.

How much deep sleep do you need?

While individual sleep varies, the general consensus is that you should aim for a minimum of 7 hours of sleep a night for optimal health. Consistently getting less than 7 hours of sleep is associated with higher risks of developing diabetes, high blood pressure, heart disease, stroke and depression.

Research indicates that women tend to require slightly more sleep than men and sleep patterns can be influenced by the menstrual cycle due to hormonal changes. This can occur more during the luteal phase (the second half of the menstrual cycle after ovulation) where some women might notice a decrease in sleep duration.

How to get more deep sleep

Try not to worry if you can’t always get enough sleep, especially if you have small children, do shift work, or have circumstances out of your control. However, there are some simple evidence-based tips for better sleep that you can try to get the most out of your time getting some shut eye.

1. Prioritise sleep: Make sleep an important part of your routine. Set a consistent bedtime and wake-up time. Creating consistent habits helps regulate your body’s internal clock and make it easier to achieve deep sleep. If you would like to learn more, check out our guide on how to improve your circadian rhythm.
   
   
2. Expose yourself to sunlight: There are many health benefits of natural light. Light entering the eye at key times during the day serves as the main cue for circadian rhythms and whole host of hormonal functions, including the release of cortisol and melatonin, temperature regulation, blood pressure control, cardiovascular function, and muscle strength.
   
   
3. Practice good sleep hygiene: Create habits that boost sleep quality and promote healthy sleep habits. Limit exposure to screens and other stimulating activities for at least one hour before bed. Blue light exposure that comes from devices like mobile phones and laptops can interfere with melatonin production, an essential sleep hormone, and make it harder to get enough deep sleep.
   
   
4. Keep your bedroom cool and well ventilated: Being too hot in bed is associated with a decrease in deep sleep, so you may want to consider taking steps to create a cooler sleeping environment. Additionally, higher levels of CO2 overnight can negatively impact the length of deep sleep throughout each sleep cycle and better sleep was reported with better “air freshness”. Why not try opening a window or using a fan to ensure circulating air?
   
   
5. Mind your diet: Eating large meals close to bedtime can make it difficult to get a good night’s sleep and play havoc with blood glucose levels. Eating raises the body’s core temperature which is the opposite of what is needed for a good night’s sleep: a lower core body temperature.
   
   Reduced deep sleep is associated with lower insulin sensitivity and an increased risk of type 2 diabetes.
   
   A 2019 systematic review and meta analysis found that glucose tolerance (the body’s ability to manage blood sugar levels efficiently) after eating was worse at night than during the day. Other research suggests that melatonin can inhibit insulin action and impact glucose metabolism. This is the process of breaking down and using glucose for energy.
   
   Your body is not primed to digest and absorb the nutrients as it is winding down for the day and melatonin levels rise. As a good rule of thumb, it is best to avoid eating around three hours before going to bed. This can also help manage symptoms if you experience acid reflux.
   
   
6. Invest in a good mattress: Research has found that a comfortable mattress can increase sleep quality and duration of deep sleep by supporting the natural curve of the spine and reduced unnecessary body movements.
   
   
7. Know when to consult a healthcare provider: If sleep problems are severe or persist, or if you suspect you might have sleep apnoea or insomnia, consult a healthcare provider or your GP. They can look at your sleep patterns, identify possible causes, and make personalised recommendations and treatment options.

Sleep and your chronotype

Your chronotype refers to your natural preference for activity and sleep patterns. You may have heard this in relation to being an ‘early bird’ or a ‘night owl’. While chronotypes are not fixed, they do have a genetic component. Your sleep can be influenced by genes such as clock genes, responsible for your body clock, and AHR which impacts how the body deals with caffeine.

Our DNA tests offer unique insights into how your unique genetic makeup can affect your sleep, helping you to make informed decisions about your health and wellbeing.

Did you know you can track your sleep quality in the Evergreen Life app? You can also receive more personalised tips on how to improve other aspects of your wellbeing such as diet, happiness and fitness. Download the app below (if you haven’t already) and take your available questionnaires to start your wellness journey and look out for your notification to complete more questionnaires including the Sleep Quality Check.

Reviewed by:

Anna Keeble MA BA Head of Content and Wellbeing Expert

Dr Claire Marie Thomas MRCGP DFSRH DTMH DipNLP MBChB BMedSci Medical Expert

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