The Benefits of Sleep &  Why Good Sleep Is Essential

The Benefits of Sleep & Why Good Sleep Is Essential

If you’ve ever had a bad night’s sleep, you’ll know it can affect pretty much every part of your day. From mood swings to cravings, exercise recovery and even the risk of serious diseases, sleep is the foundation upon which all other aspects of our health stand. Statistics show that in the UK, 71% of adults don’t get the recommended 7 to 9 hours of sleep per night, whilst one in seven survive on just five hours, which can be dangerously low. In the USA, the average sleeping time is around 7 hours 18 minutes, going to bed at 11:39 and waking up at 7:09am. Research shows those who consistently keep up that sleep schedule tend to rate their mood upon waking at 57 out of 100, and spend an average of 23.95 minutes snoring too. [2] Across the globe, 62% of adults say they don’t sleep as well as they’d like, [3] whilst as much as 50% of children will experience a sleep problem that is highly likely to impact their wellbeing. [4]

If so many of us sleep so badly, it seems important to ask why sleep is such a vital part of our health, what exactly is causing poor sleep across the world, and how to improve sleep? In this 2-part blog series, you’ll discover the tools, tips, nutrition and supplements to optimise your sleep, and the key biohacking protocols to help you sleep deeper, and feel more energised the next day. First though, you’ll need to know what happens when we sleep, the parts of life that alter sleep quality, and how the body responds to both good and bad sleep.

What is sleep?

Before the 1950s, most people believed sleep was a passive activity during which the body and brain were dormant, but more recent research shows that the brain and body are both engaged in a number of activities necessary for both surviving and thriving. Sleep is generally characterised as a state of altered consciousness, relatively inhibited sensory activity, and reduced muscle activity, but some parts of the brain are actually more active whilst we’re snoozing than when we’re awake. We sleep on average for a quarter to a third of our lives, moving through several stages and cycles of sleep. [5]

The stages of sleep:

1. NREM1 sleep (non-rapid-eye-movement-sleep): 1-5 minutes

This is the transitional phase between wakefulness and sleep, when the brain is in a ‘hypnogogic state’. This is when you’ll feel like you’re ‘dozing off’, the body hasn’t completely relaxed, and you may experience ‘twitching’ or the sensation of ‘falling’. It’s usually easy for someone to wake up at this stage. It also happens to be a brain that is most conducive to hypnosis, and produces Alpha brainwaves of 8-13hz. Alpha brainwaves are also related to the ‘flow state’, when the brain is calm, creative, and able to more readily absorb new information.

2. NREM2 sleep: 10-60 minutes

The second stage of sleep sees the body more subdued and relaxed. Temperature drops, and brain activity slows, although there are short bursts of activity that actually aid in preventing the body being woken up by external stimuli, known as ‘sleep spindles’. Theta waves are the dominant brainwave present, between 4-8hz, and experts believe they help with processing information and consolidating memories.

3. NREM3 sleep: 20-40 minutes

This is the ‘deep sleep’ phase, when muscle tone, pulse and breathing all soften and slow. It’s harder for someone to wake up in this stage, and brainwaves are dominated by Delta waves or ‘slow waves’, between 1-4hz. It is thought that the Delta phase of sleep is critical to restorative sleep, and is the part of sleep when healing, recovery and repair primarily take place. Growth hormone is released during deep sleep, which is important for maintaining, building and repairing healthy tissue in the brain and other organs. It is also vital for speeding up healing of injuries and repairing muscles after exercise. This phase can also help strengthen the immune system, and contributes to insightful thinking, creativity and memory.

4. REM sleep: 10-60 minutes

In the 4th stage of sleep, brain activity picks up, preparing for wakefulness. At this time, the body also experiences ‘atonia’, which is a natural temporary muscle paralysis (other than the eyes and respiratory muscles). REM sleep is essential for cognitive functions like memory, learning and creativity, and this stage is most known for vivid dreaming. Dreams can indeed occur in any sleep stage, but they’re most vivid and intense in the REM phase due to the sharp increase in brain activity. Usually, REM sleep doesn’t occur until around 90 minutes of a sleep cycle, but new-borns spend around 50% of their sleep in the REM state, which is between 4-8hz.

Why is sleep important?

Since the introduction of trackers like Fitbit, Whoop, Apple Smartwatches and Oura rings, those who use these devices are able to monitor how well or how poorly they’ve slept, and are advised to change their daily activities accordingly. With more data and research than ever, we’re beginning to learn more about the mechanisms of sleep, and just why it’s so vital.

Sleep is so important because whilst we’re asleep, the body is working to support healthy brain function and physical health. In children and teens, sleep supports growth and development, whilst in adults, sleep helps prevent the onset of Alzheimer’s and dementia. Sleep plays a huge role in learning and neuroplasticity, immune health, hormonal balance, as well as cognitive performance, exercise recovery, blood pressure, appetite and cardiovascular health. [6] Sleep deprivation and disrupted sleep can quickly cause all of these aspects (plus many more) to deteriorate quickly. 

There are several factors that directly affect how long and how well we sleep. In our next blog on sleep, you’ll learn all the tools, tips, supplements and nutrients you need to biohack your sleep. First however, it’s vital to know what’s actually wrecking your sleep, and what could be helping it. These are the key aspects that influence your sleep:

Light: Research shows that when our eyes are exposed to light at the wrong time of day, this can disrupt our circadian rhythms (the sleep-wake cycle). In order to get a good night’s sleep, our brains must release the hormone melatonin, which is synthesised and released when stimulated by darkness. [7] Melatonin not only acts on receptors to encourage the onset of sleep, but it’s also one of the most powerful antioxidants in existence, repairing cells and tissue from damage, and preventing disease every night. One of the biggest problems related to sleep is that many of us sit in brightly lit homes watching bright screens just moments before going to bed. The light emitted from these devices suppresses melatonin secretion, which in turn makes it difficult to drop off and experience truly restorative sleep. [8]

The time of day we do need lots of bright light exposure is in the morning, soon after waking. Getting outside into bright natural light helps re-set the body clock and will promote a better night’s sleep that evening. It also helps raise dopamine levels, linked to motivation, drive and an elevated mood. We’ll get more specific on exactly how to work with light and darkness to optimise your sleep in the next sleep blog, but if you can keep a regular schedule with the amount of light and darkness you’re exposed to, this can work wonders for your sleep.

Darkness: Now you know we need darkness in order to promote healthy sleep, but just how dark does it need to be? Research shows that if our eyes are exposed to light between 10pm and 4am, this can severely disrupt not only sleep, but our levels of wakefulness the next morning. Overhead lights are especially problematic, as they mimic bright daytime sunlight. Aim to have the bedroom as dark as possible at night; use blackout blinds, an eye mask, taping over small lights emitted from various sources, and definitely keep your phone on airplane mode or switched off at night. [9]

Temperature: If you’ve ever woken up in the night needing to throw the duvet off and cool down, you may want to reconsider your bedding and the temperature of your bedroom. Sleep is directly influenced by temperature; our circadian rhythms dictate that our bodies should cool down at night, and warm up in preparation for waking up. A very warm bedroom can interrupt the normal physiology of sleep; research shows that elevated ambient temperatures can prevent core body temperature from reducing, and that elevated core body temperature is associated with poor sleep. [10]

Hormonal Balance & Life Stage: Women experiencing perimenopause and menopause may be familiar with night sweats and hot flashes, which can disrupt sleep. Whilst mainstream thought for a long time was that the hot flashes themselves caused night time waking, new research suggests that waking at night could actually be the cause of night sweats and hot flashes. Various supplements and medications are often prescribed to help with menopausal sleep issues, but maintaining the basics of a regular sleep schedule, avoiding alcohol and caffeine, as well as avoiding excessive bright light at night are all effective too. [11]

Nutrition & Supplementation: In our next sleep blog, we’ll discuss in detail the specific nutrients and supplements you need to improve sleep. For now, it’s worth remembering that eating too close to bedtime can disrupt sleep, but that being hungry in the middle of the night can disrupt sleep too. Balancing your blood sugar is key when it comes to getting good quality slumber, and many people find that consuming whole-food carbohydrates with their evening meal helps induce relaxation, quicker sleep onset, and improved sleep. [12]

Exercise: Exercise raises adrenaline and dopamine, and many forms of exercise can raise cortisol too. These are all hormones we don’t want flooding the body when we’re trying to get to sleep. To help regulate circadian rhythms, it’s best to engage in any vigorous exercise in the morning, and more relaxing forms of movement at night. If the only time you’re able to exercise is in the evening, try to finish at least 3 hours before bed.

Caffeine and Alcohol: Throughout the day, levels of the hormone adenosine build up in the body. When they reach a peak, we feel tired and ready for bed. Caffeine acts to prevent the build-up of adenosine, which is why we feel less tired when we drink it. Some people however, can seem to drink a cup of coffee at night and sleep soundly, whilst others experience sleep disturbances if they consume caffeine any time after around 12 noon or 1pm. This is all related to how each person metabolises caffeine. Slow metabolisers tend to get jittery and stay wired up to nine hours after drinking caffeine, whilst fast caffeine metabolisers simply feel more energetic and alert for a couple of hours. Depending upon how you feel, it may be worth curbing your coffee habit at least 9 hours before bed. [13] Alcohol also disrupts sleep by causing us to spend less time in the REM stage, with the end result meaning we wake up feeling less refreshed. Alcohol can also disrupt blood sugar levels and body temperature – two other key players when it comes to getting sound sleep.

Circadian Rhythms: Our bodies are wired up to natural circadian rhythms – also known as the sleep-wake cycle. Circadian rhythms are physical, mental and behavioural changes that follow a 24-hour clock. Throughout the rhythm of each day, we receive triggers from our environment as to how we should behave, which hormones the body should release, and therefore how balanced and healthy we’ll be. Everything we’ve discussed above is a signal or trigger to the body, so in order to rebalance your circadian rhythms, it’s essential to ensure your environment is sending you the right signals at the right time. We’ll discuss this in much more detail next time, but for now, remember that light, darkness, food, exercise, stress and temperature are all having a big impact on your sleep every night.

Stress and cortisol: As well as circadian rhythms, our bodies also have cortisol rhythms, which you may have read about in our previous biohacking blog on Biohacking Your Cortisol For Less Stress, More Energy & Better Sleep. Cortisol is known as the ‘stress hormone’, but is plays important roles in other aspects of life. Cortisol should actually be relatively high in the morning, and drop right down at night. If you feel ‘wired and tired’ and can’t get to sleep, cortisol could be playing a role, and reducing stress at night is something you’ll want to focus on.

How much sleep do I need?

So, before we take a quick look at four essential benefits of sleep, how much sleep do we really need? The advice generally states that adults need between 7 to 9 hours of sleep each night. This does of course change depending upon life stage and health circumstances though. Newborns need 14-17 hours, children aged 6-12 need 9-12 hours, teenagers need 8-10 hours, adults need 7-9 hours, whilst those 65 and older are thought to need 7-8 hours sleep per night. [14] Keep in mind that if you’re dealing with a chronic illness, heavy work schedule or demanding exercise regime, you may need more sleep. Some biohackers like Dave Asprey say they sleep for as little as 6 hours 10 minutes, but that their quality of sleep is extremely high. Stay tuned for our next blog on biohacking your sleep if you want to know how you could access this ability too. 

Four Essential Benefits of Sleep

Finally, let’s look at four essential benefits of sleep, so you can understand just how vital a good night’s rest is:

1. Sleep and Weight Gain

Disrupted sleep can cause blood sugar swings, cravings, appetite disturbances and is a leading cause of obesity. Research shows that sleep issues are associated with insulin resistance, and multiple studies confirm that disrupted sleep for multiple nights in a row can drastically increase the risk of prediabetes, and worsen the symptoms of those who currently suffer with the condition. [15] Wildly swinging blood sugar levels often lead to sugar cravings, and the lack of sleep also changes our appetite and satiety signals; increasing ghrelin (the hunger hormone) and suppressing leptin (the ‘fullness’ hormone) so we’re more likely to over-eat too.

2. Sleep and Brain Health

When we’re asleep, the glymphatic system works hard to ‘sweep away’ debris and damage from the brain and central nervous system, and recent research shows this is one of the most important factors in preventing Alzheimer’s and dementia. [16] [17] Sleep also aids the brain in consolidating everything we’ve learnt that day, and in creating and changing neural pathways, which allows us to retain information, change habits and maintain healthy memory.

3. Sleep and Exercise Recovery

In the deeper stages of sleep, the flow of blood and oxygen is increased to the muscles, improving exercise and injury recovery. Sleep helps reduce excessive inflammation which may damage tissues, and helps improve athletic performance and reaction time too. Poor sleep is associated with slow muscle recovery, increased stress levels, decreased glycogen synthesis, and increased ratings of perceived exertion. If exercise is a central aspect of your life, improving sleep is absolutely vital. The biggest pulse in growth hormone occurs whilst we’re asleep too, so if you want to build muscle, ensure you’re optimising your sleep.

4. Sleep and Mental Health

Not only is sleep important for how we move and think; it’s essential for how we feel too. Poor sleep is associated with elevated levels of cortisol and stress, as well as a reduced ability to handle stressful situations. Research even shows that sleep disorders are core symptoms of depression, [19] but that depressive symptoms can also be caused by improper sleep too. Optimising your sleep however, can help improve your creativity, problem-solving ability, reduce likelihood of depression, enhance the processing of emotions, and even extend lifespan.

Look out for our next blog on biohacking your sleep and improving every single aspect of your wellbeing in the process. Until then, work on improving the basics; can you turn down the lights in your home at night? Reduce caffeine after midday? Add some healthy carbs to your evening meal, or cool down your bedroom to improve your sleep? Even small changes can make a big difference.

  • [1] Direct Line Group. (2022). Sleeping dangerously: 7.5 million Brits have under five hours' a night. [Online]. Direct Line Group. Last Updated: February 2022. Available at: [Accessed 7 February 2023].
  • [2] Sleep Cycle. (2019). What we know about America’s healthiest, happiest and best-rested people. [Online]. Sleep Cycle. Last Updated: February 2019. Available at: [Accessed 7 February 2023].
  • [3] (2023). Sleep Statistics 2023. [Online]. The Checkup: Singlecare. Last Updated: February 3rd 2023. Available at:,Global [Accessed 7 February 2023].
  • [4] (2023). Sleep Statistics 2023. [Online]. The Checkup: Singlecare. Last Updated: February 3rd 2023. Available at:,Global [Accessed 7 February 2023].
  • [5] Johns Hopkins. The Science of Sleep: Understanding What Happens When You Sleep. [Online]. Johns Hopkins. Available at: [Accessed 7 February 2023].
  • [6] (2013). The benefits of slumber. [Online]. NIH News In Health. Last Updated: April 2013. Available at: [Accessed 7 February 2023].
  • [7] Grivas TB, Savvidou OD. Melatonin the "light of night" in human biology and adolescent idiopathic scoliosis. Scoliosis. 2007 Apr 4;2:6. doi: 10.1186/1748-7161-2-6. PMID: 17408483; PMCID: PMC1855314.
  • [8] Blume C, Garbazza C, Spitschan M. Effects of light on human circadian rhythms, sleep and mood. Somnologie (Berl). 2019 Sep;23(3):147-156. doi: 10.1007/s11818-019-00215-x. Epub 2019 Aug 20. PMID: 31534436; PMCID: PMC6751071.
  • [9] Plos Biology. (2022). Recommendations for daytime, evening, and nighttime indoor light exposure to best support physiology, sleep, and wakeful. [Online]. Plos Biology. Last Updated: March 2022. Available at: [Accessed 7 February 2023].
  • [10] Science Advances. (2017). Nighttime temperature and human sleep loss in a changing climate. [Online]. Science Advances. Last Updated: May 2017. Available at: [Accessed 7 February 2023].
  • [11] Sleep Problems and Menopause: What Can I Do?. [Online]. NIA. Available at: [Accessed 7 February 2023].
  • [12] (2007). Carbs May Help You Fall Asleep Faster. [Online]. WebMD. Last Updated: Feb 2007. Available at: [Accessed 7 February 2023]
  • [13] (2007). Carbs May Help You Fall Asleep Faster. [Online]. WebMD. Last Updated: Feb 2007. Available at: [Accessed 7 February 2023]
  • [14] How much sleep do I need?. [Online]. CDC. Available at: [Accessed 7 February 2023].
  • [15] The impact of poor sleep on type 2 diabetes. [Online]. NIH. Available at: [Accessed 7 February 2023]
  • [16] Jessen NA, Munk AS, Lundgaard I, Nedergaard M. The Glymphatic System: A Beginner's Guide. Neurochem Res. 2015 Dec;40(12):2583-99. doi: 10.1007/s11064-015-1581-6. Epub 2015 May 7. PMID: 25947369; PMCID: PMC4636982.
  • [17] Reeves BC, Karimy JK, Kundishora AJ, Mestre H, Cerci HM, Matouk C, Alper SL, Lundgaard I, Nedergaard M, Kahle KT. Glymphatic System Impairment in Alzheimer's Disease and Idiopathic Normal Pressure Hydrocephalus. Trends Mol Med. 2020 Mar;26(3):285-295. doi: 10.1016/j.molmed.2019.11.008. Epub 2020 Jan 18. PMID: 31959516; PMCID: PMC7489754.
  • [18] Advance sleep medicine services. How does sleep affect exercise recovery?. [Online]. Advance sleep medicine services. Available at: [Accessed 7 February 2023].
  • [19] Nutt D, Wilson S, Paterson L. Sleep disorders as core symptoms of depression. Dialogues Clin Neurosci. 2008;10(3):329-36. doi: 10.31887/DCNS.2008.10.3/dnutt. PMID: 18979946; PMCID: PMC3181883.

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