Why Is Sleep So Important?

One of the most underutilized methods of recovery and regeneration is adequate sleep. In this blog post I will discuss some of the key reasons a good night's sleep is critical for optimal physical condition and mental performance!

The key driver behind our sleeping pattern is an internally controlled pattern called a ‘Circadian Rhythm’.

The Circadian Rhythm is a 24 hour cycle that regulates our internal systems, highly influenced by external factors [1] - primarily daylight exposure - to allow our body to adapt as best as possible to the world around us. In relation to sleep all the external stimuli that surround us at almost any time of the day with the artificial lights in our homes and on our smartphones has been shown to have a negative effect on sleeping patterns. The primary way in which this artificial light reduces the quality of your sleep is by suppressing the production of melatonin - a hormone triggered by exposure to dark/light and critical to your ability to sleep well.

Negative effects of Poor Sleeping Habits

There are several negative outcomes associated with poor sleeping habits, below are just a few!

Inhibits Weight Loss

Lack of sleep can affect your body in many ways but I will start with one of the ways in which a lack of sleep can interfere with the good work that you may be doing in the gym.

A lack of adequate sleep is linked to obesity and weight gain and there a number of reasons behind this.

Studies have shown that those who suffer from chronic sleep deprivation have altered levels of ‘hunger hormones’ leptin and ghrelin - compared to those who have a regular and sufficient sleep cycle. [2]

‘Ghrelin’ is the hormone that makes you feel hungry and ‘Leptin’ is the hormone that makes you feel full. When sleep decreases your body compensates by increasing ghrelin levels and decreasing leptin levels - making you feel hungrier and making it harder for you to resist the cravings for extra food and therefore, extra calories.

Insufficient sleep is also linked to increased levels of cortisol - this can lead to craving of high sugar, high fat foods that are highly palatable and easy to overconsume. [3]

Recovery and Regeneration

During resistance exercise our muscles break down and the process through which they grow back and repair is what makes them stronger.

Lack of adequate sleep can interfere with this process and lead to inadequate recovery from your gym sessions - meaning that you are not getting the full benefits and growth that could be possible.

What is the point of committing to come to the gym 3 or more times a week to get stronger and leaner, if your habits outside the gym are inhibiting your progress?

You need sufficient and deep sleep to allow your body to produce enough growth hormone to repair and regenerate your muscles, cells and tissues. A chronic lack of sleep will affect your body in that you will not recover adequately and you will be fatigued. This will increase your risk of injury and slow down your physical progress - both in terms of losing body fat and getting stronger. [4]


Studies have shown that sleep is important and directly linked to better physical and mental performance on both a general and elite level.

A study of elite athletes noted that when their sleep was extended over a prolonged period - their athletic capacity improved both in terms of their consistency of skill execution and their overall markers of athleticism such as speed. [5]

In a study of over 2,500 older women - those who slept poorer exhibited weaker grip strength (a very important and reliable predictor of health in older age) and walked slower as they went about their day. [6]

Another study showed that lack of sleep affected the cognitive performance of the brain as much as intoxication from alcohol - a consideration if you are in a job that requires you to maintain consistent focus and concentration as a prerequisite such as a driver or an operator of heavy machinery. [7]


New motor pathways are forged during sleep - so depriving your body of the rest it needs is going to hold back your ability to learn new processes.

If you are learning a new skill such as a language in school, serving in tennis or a deadlift in the gym - if you do not give your body time to sleep and forge these new mental pathways or consolidate your memories, the learning process will be slower than with adequate amounts of sleep.

The second way in which sleep deprivation can stunt mental growth is through the inability to focus and concentrate during your active hours - if you are sleep deprived the cognitive performance of your brain suffers and you will not be able to process and internalise information as well as if you were in a well-rested and refreshed state.

The same way in which sleep is critical for physical growth, it is similarly critical for mental growth. [8]

How can I improve my sleep quality?

There are some simple steps you can take to improve your sleep quality and here are 3 that I think most will be able to implement easily into their daily/nightly routines.

Early to bed, early to rise!

The circadian rhythm of your body is controlled not only by what you do in the time immediately preceding when you go to bed - but by what you do from the time you wake up in the morning [4]

Allow yourself time to wake up gradually and give your body the time to go through its natural waking patterns. The best way of doing this is by getting to bed early enough and aim to get enough sleep - the ultimate aim would be to wake up at the desired time without an alarm clock. Easier said than done if you are in a 6 AM class!

Electronic Free Bedroom

Another effective method of improving your sleep quality might be leaving your smartphones downstairs and deem the bedroom an electronic free zone - protecting you from the blue light emitted by devices that can suppress the production of melatonin when used late at night [4] This also means that when you wake up in the morning, the first thing that your reach for won’t be your smartphone - allowing you to wake up more gradually without being bombarded by the information and stimuli provided by the smartphones.

Use Coffee Smarter

Using caffeine as a strategic performance enhancer is okay but using it as a tool to get you to the point where it helps you to get through the day is not ideal!

Coffee has multiple benefits including performance enhancement, being linked to lower rates of degenerative brain conditions and heart diseases and improving alertness by manipulating adenosine receptors but excessive use can have negative side effects. [9]

Consistent excessive consumption (400mg caffeine per day is the recommended amount by the UK Food Standards agency) can decrease sensitivity to caffeine's effects. This means that people drink more in search of the initial ‘hit’, in reality all that happens is they are so desensitized to caffeine that they need a basic amount of caffeine to allow them to reach their base level of performance and are unable to access the benefits as easily as those who use caffeine more responsibly.

Maybe consider using coffee and caffeine sparingly before a big meeting or workout in order to peak mental alertness or to access the ergogenic (performance) benefits of coffee.

If you are a coffee drinker and consume over 400mg almost every day (1 Starbucks Grande Brewed Coffee contains 330 mg) or regularly find yourself unable to function until you have coffee - it is possible that you may be desensitized to the effects and a period of ‘deloading’ from caffeine will reduce tolerance. This will allow you to drink coffee and start to enjoy the benefits of caffeine with lower dosages.

If you are interested in finding out more about the science of sleep there is a book called ‘Sleep’ by Nick Littlehales that I highly recommend!

See you in the gym,



[1] Sleepfoundation.org. (2018). What is Circadian Rhythm?. [online] Available at: https://sleepfoundation.org/sleep-topics/what-circadian-rhythm [Accessed 12 Mar. 2018].

[2] Taheri, S., Lin, L., Austin, D., Young, T. and Mignot, E. (2004). Short Sleep Duration Is Associated with Reduced Leptin, Elevated Ghrelin, and Increased Body Mass Index. PLoS Medicine, 1(3), p.e62.

[3] Layton, J. (2018). Is a lack of sleep making me fat?. [online] HowStuffWorks. Available at: https://science.howstuffworks.com/life/sleep-obesity1.htm [Accessed 12 Mar. 2018].

[4] Littlehales, N. (2016). Sleep. Penguin Books.

[5] Mah, C., Mah, K., Kezirian, E. and Dement, W. (2011). The Effects of Sleep Extension on the Athletic Performance of Collegiate Basketball Players. Sleep, 34(7), pp.943-950.

[6] Goldman, S., Stone, K., Ancoli-Israel, S., Blackwell, T., Ewing, S., Boudreau, R., Cauley, J., Hall, M., Matthews, K. and Newman, A. (2007). Poor Sleep is Associated with Poorer Physical Performance and Greater Functional Limitations in Older Women. Sleep, 30(10), pp.1317-1324.

[7] HuffPost. (2018). Studies Show Sleep Deprivation Performance Is Similar to Being Under the Influence of Alcohol. [online] Available at: https://www.huffingtonpost.com/lissette-calveiro/studies-show-sleep-deprivation-performance-is-similar-to-being-under-the-influence-of-alcohol_b_9562992.html [Accessed 12 Mar. 2018].

[8] Healthysleep.med.harvard.edu. (2018). Sleep, Learning, and Memory | Healthy Sleep. [online] Available at: http://healthysleep.med.harvard.edu/healthy/matters/benefits-of-sleep/learning-memory [Accessed 12 Mar. 2018].

[9] Physiqonomics. (2018). The Science of Caffeine: Illustrated. [online] Available at: http://physiqonomics.com/caffeine-illustrated/ [Accessed 12 Mar. 2018].

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