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Why do we sleep?

Why do we sleep?

Sleep is when the brain rests and repairs

As the modern pop sensation Billie Eilish sings, where do we go when we sleep? No one knows the true bio-evolutionary purpose of sleep but modern science has identified a few things that are crucial to the body running properly. Here is how you can improve your sleep.

How Sleep Works

Neuroscience tells us that our master switch deep in our brain acts as our master biological clock. Light sensitive cells in our retinas feeds signals deep into that brain switch. This trains brain neurons to sync up with Earth’s 24 hour cycle of day and night. We call these Circadian rhythms. These are the control switch which tells us when to feel sleepy or awake. When the world goes dark, this master switch tells our pineal gland to increase the hormone melatonin levels in the bloodstream, acting like a chemical lullaby.

Sleep is restorative

Sleep seems to have many restorative functions and although the brain’s intense electrical activity uses 1/4 of the entire body’s energy supply, it never stops working. However, it uses the time you sleep to do the ‘repair and maintenance of the brain, body and blood circulation. It rebuilds cells, synthesises protein and lowers blood pressure and heart rate as you sleep.


Sleep with the sun’s cycle

All of this means: When it’s dark, it’s time to go to bed. However, modern society has changed the definition of dark with light pollution in cities and blue light from our devices. Our brain doesn’t know better that the sun is shining which can lead to sleep deprivation.

We need to combat this by simulating dark and cool conditions in the bedroom and staying away from activities that stimulate the brain before bed.

Negative effects of sleep deprivation

Inadequate sleep duration in the general population has been associated with a myriad of negative health effects including neurocognitive, metabolic, immunologic and cardiovascular dysfunction. People who are sleep deprived may have impaired brain function that could affect judgment and/or decision-making during athletic performance. Improving your sleep can have a big impact on the quality and speed of your recovery from physical injury.

Impaired sleep affects your metabolism

From a metabolic standpoint, sleep deprivation has been associated with obesity and diabetes. Sleep-deprived individuals may crave unhealthy foods and show impairments in glucose sensitivity, which may impair glycogen repletion and potentially affect appetite, food intake, and protein synthesis. Remember, healthy eating is the first step of healthy living!

Poor sleep affects your hormones

Impaired sleep also negatively affects growth hormone and cortisol secretion. Sleep deprivation increases pro-inflammatory cytokines, which impairs immune system function, impedes muscle recovery and repair from damage, leads to autonomic nervous system imbalance (simulating overtraining symptoms), results in slower/less accurate cognitive performance, and alters pain perception.

Dangers of poor sleep

According to sleep scientist Matt Walker, men who routinely sleep less than 5 hours of sleep, show testosterone levels of a man 10 years their senior. They also have significantly smaller testicles than men who sleep more than 7 hours a night! We also see an equivalent reaction on female reproductive health for women.[ii] When Matt Walker researched people who got more than 8 hours of deep sleep daily, they showed brain waves that improve memory and slow down the aging process. Disruption of deep sleep is an underappreciated factor that is contributing to cognitive decline and increasing likelihood of Alzheimer’s disease according to the most recent studies.

Sleep deprivation is proven to decrease athletic performance

In conclusion, there are clear negative effects of sleep deprivation on performance, including reaction time, accuracy, vigor, strength, and endurance. Cognitive functions such as judgment and decision-making also suffer. Sleep extension can positively affect reaction times, mood, and even athletic performance. Improving the quality of sleep will help you feel more alert, retain memories better and live with more vitality.

Sleep disorders

Many different sleep disorders exist, and often people remain undiagnosed and untreated. Sleep apnea is a common condition that affects at least 10 % of the adult US population.[i] Although typically considered a disease of obese men, lean individuals including elite athletes may suffer from this problem. Similarly, insomnia is a common condition that can be treated effectively if the problem is recognized and appropriately addressed. Sleep apnea is another common disorder which is basically heavy snoring. This can be diagnosed and treated! If you snore heavily go get a sleep test. 80% of people who have it are undiagnosed and sleep apnea is a killer. The treatment is a simple facemask that opens up the airway and has dramatic results with sleep improving and delaying onset of Alzheimer’s Disease and other issues!

Even in people without sleep disorders, insufficient sleep duration has negative health effects that can impact all aspects of an individual’s well-being. Improving your sleep can have a drastic effect on the rest of your health.

Limit screen time before bed

Furthermore, blue-light emissions from screens disrupt the body’s natural melatonin production which helps regulate one’s circadian rhythms, and can affect next-morning alertness. Sleep habits are affected by extensive exposure to electric light and evening use of electronic media devices. One thing we recommend is avoiding all screens before bed and making an effort to do some sleep journaling.

Keeping a sleep journal

  • Vent your frustrationsDocument your troubles
  • Keep a gratitude journalMore positivity before bed
  • To-do listQuiet anxious thoughts and help clear your head

Bedtime worry is a significant factor in difficulty falling asleep. By slowing down and sorting your thoughts and emotions before bed will improve mental health. This help you improve your sleep by getting the deep, sound sleep that your body needs to function optimally!

In fact, a 2018 study by Baylor University required fifty-seven healthy students to do one of the following each night five minutes before bed: Create a to-do list for the following few days, or compile a list of tasks that they have completed each day. Participants who created a to-do list each evening actually fell asleep significantly faster than those who noted their completed tasks for the day.

6 tips on improving sleep habits:

  1. Regularity – Anchoring your sleep will improve quality and quantity of sleep whether on a weekday or a weekend. Your brain has an internal 24 hr clock that expects regularity. Set a ‘go-to-bed’ alarm if you must.
  2. Body temperature – Keep it cool. Your brain and your body need to drop their core temperature by 1 degree Celsius or around 3 degrees Fahrenheit in order to initiate sleep, and also stay asleep. This is why it’s easier to sleep when it’s too cold rather than too hot. Aim for a bedroom temperature of a little over 18 degrees Celsius.
  3. Darkness – We need darkness in the evening to release the hormone melatonin which helps regulate the healthy timing of our sleep. In the last hour before bed, stay away from electronic devices and dim down all the lights in the house. Use black-out shades or even wear an eye-mask if you must.
  4. Walk it out – Don’t stay in bed awake for long periods of time. If you can’t fall asleep for 25mins, we recommend getting out of bed to do anything else, even take a walk. Your brain is an associative device and has learned that bed is a trigger for wakefulness and by doing something else you break that association. Only return to bed when sleepy so your brain can ‘relearn’ this association that bed is for sound sleep.
  5. Monitor alcohol, caffeine and stimulants – Try to stay away from caffeine late in the evenings and try not to go to bed when you are inebriated. Make sure you don’t eat or drink right before bed.
  6. Wind down routine – Don’t expect to dive into bed and fall asleep, sleep as a physiological process is more similar to landing a plane, you need to gradually disengage from stressful and stimulating activities like your computer and do something relaxing. Try reading, but avoid doing it in bed (see tip 4 above).

Think of sleep like a life support system. You need good quality, regular sleep to make sure your body runs smoothly. Improve your sleep, improve your life!


  • Fullagar, Hugh & Skorski, Sabrina & Duffield, Rob & Hammes, Daniel & Coutts, Aaron & Meyer, Tim. (2014). “Sleep and Athletic Performance: The Effects of Sleep Loss on Exercise Performance, and Physiological and Cognitive Responses to Exercise.” Sports Medicine. 45. 10.1007/s40279-014-0260-0.
  • Venter, Rachel. (2012). Role of sleep in performance and recovery of athletes: A review article. South African Journal for Research in Sport, Physical Education and Recreation. 34. 167-184.
  • Physical recovery, mental detachment and sleep as predictors of injury and mental energy.
    Yannick A Balk, Jan de Jonge, Wido GM Oerlemans, Sabine AE Geurts
    Journal of Health Psychology
    Volume: 24 issue: 13, page(s): 1828-1838
    Article first published online: May 3, 2017; Issue published: November 1, 2019
  • International Journal of Sports Medicine
    2019 Aug; 40(8): 535–543.
    Published online 2019 Jul 9.
  • Sleep Deprivation and the Effect on Exercise Performance
    Van Helder, T., Radomski, M.W. Sleep Deprivation and the Effect on Exercise Performance. Sports Medicine 7, 235–247 (1989)
    Published07 October 2012 Issue Date April 1989
  • Sports Medicine – Open volume 4, Article number: 34 (2018)
    Nedelec, M., Aloulou, A., Duforez, F. et al. The Variability of Sleep Among Elite Athletes. Sports Med – Open 4, 34 (2018).
  • Journal of Experimental Psychology Gen. 2018 Jan; 147 (1): 139-146
    Published online 2017 Oct 23
    The Effects of Bedtime Writing on Difficulty Falling Asleep: A Polysomnographic Study Comparing To-Do Lists and Completed Activity Lists.
    Michael K. Scullin, Ph.D., Madison L. Krueger, Hannah K. Ballard, Natalya Pruett, and Donald L. Bliwise, Ph.D.

[i] Venter 2012
[i] Balk and De Jong 2019
[ii] Fullaghar and Skorski 2014
[iii] Balk and De Jong 2019

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Eric A
September 3, 2021 Reply

I guess it’s time to remove the iPad from the bedroom :/ Thanks for this very helpful overview on sleep.

    Hands admin
    September 3, 2021 Reply

    good quality of sleep is very essential for our health so I will remove my iPad too 😂

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