Sleep and Fitness: A Broken Relationship

We all know that getting a good night sleep is something we should aim for every night but how many of us actually prioritise our sleep? We are now going to bed much later with some of us hitting the hay around midnight, the time that should be the ?middle’ of the night. Do you make the decision at 9 or 10 pm to get a good night sleep or instead choose to watch another episode of your favourite Netflix show? It is a tricky one for most and you may not be aware of the impact your lack of sleep is having on you.

For years, I struggled with energy during the day and found that it took me ages to get going in the morning. I would find it really hard to get myself out of bed and I would live off caffeine to keep me productive. My progress in my training was really slow and my motivation to train was also really poor. Today I see colleagues, family members and friends with similar issues on a daily basis and I am sure some of you can also resonate with such issues. It took me a long time to make the connection between these poor energy levels and my lack of sleep. Nowadays, I have made my sleep pattern much more of a priority each day and I have noticed dramatic differences in my daily schedule especially with my productivity at work and in my training.

We all know that not getting a proper night sleep will negatively affect our mood and performance the following day. However, most people are not fully aware of how impactful sleep can be to our overall health and how it can drastically slow down our fitness goals of burning fat and building muscle. If your fitness goal is to get leaner or build muscle and you have stalled in your progress despite being on point with your training and nutrition, then look at your sleep quality. If you are finding that your productivity at work is dropping and your energy and mood is off, ask yourself the following questions:

  • Am I getting 7 to 8 hours of sleep per night?
  • Do I wake up in the middle of the night?
  • Do I feel wired and alert in the evening?
  • Do I wake up feeling tired?
  • Does it take me a long time to fall asleep?

If you have answered yes to any of the following questions, then you have to work on your sleep as it is affecting your performance every day.

Poor sleep affects your body with its impact on your hormones. Such hormones include your melatonin, cortisol, growth hormone and insulin. To achieve maximum results in your training, body composition and productivity each day, then these hormones need to be in balance.

Melatonin Production:

Also known as the ?hormone of darkness?, melatonin is created by your body when it gets dark and basically tells your brain when it is dark and when it is time to sleep. Produced in the pineal gland in the center of the brain, this hormone is the driver behind our healthy sleep cycles and also a key player in energy metabolism which is important for fat loss. Our melatonin creation has been largely affected in recent times due to our exposure to artificial lights as our body thinks that it is still daytime long after the sun has gone down. If you are someone who wakes up in the middle of the night, you will be interrupting your melatonin production especially if you turn on the light. If you do regularly wake up, my advice is not to turn on the light or look at your phone. In fact, exposure to artificial light like your mobile phone or IPad before bed can delay melatonin release for up to 3 hours and will therefore impact your quality of deep sleep which will result with you feeling groggy the following morning!

Growth Hormone:

Whether your fitness goal is to gain size and muscle or get lean, your growth hormone will play a key role. If growth hormone levels are low, burning fat and building lean muscle can become very difficult. The majority of growth hormone is produced during your deep sleep, especially in the first two hours. Unfortunately, as we get older, especially after our twenties, our levels of growth hormone begin to decrease and our lack of sleep only adds to this. In fact, males who only receive 5 to 6 hours of sleep per night will have the same level of testosterone (essential for muscle strength and fertility) of someone 10 years older! 


The controlling factor of our blood sugar levels, a lack of sleep will affect your insulin hormone and make things very difficult for you especially if your goal is fat loss. I can personally testify to this. When I am trying to shed some fat, my cravings for sugar is much worse when I have not had a proper night sleep. An imbalance in your blood sugar levels is a major effect of sleep deprivation. When you are low in energy, you are constantly looking for that ?pick me up? and this can be highly detrimental to your fat loss goals. With a good night sleep, your cravings for sugary foods will reduce dramatically.


Known as the stress hormone, our cortisol levels are naturally produced when we wake up in the morning and gradually decrease as the day progresses into the evening. Cortisol is part of our built-in survival mechanism developed from our ancestral times to help us stay alert and deal with stressful situations. Referred to as our ?flight or fight mode?, this stress hormone was historically important for our ancestors to stay alert for immediate threats while living on the plains of the savannah! However, because of the demands and stresses of today?s society, our bodies are releasing much higher levels of cortisol on a regular basis, so it is therefore really important to get into a relaxed state as the evening winds down.

For most people, cortisol levels can be quite high throughout the day and night and this makes it difficult for people to fall asleep as they have so many things going on in their mind. This was something that I struggled with for a long time, however by implementing a few useful strategies such as writing a to-do list and putting my phone on airplane mode an hour before bed, I have found that I am able to switch off a lot better. If you struggle to switch off late at night, your cortisol levels may be higher than they should be so my advice is to take a look at your nighttime routine. Try not to watch television too late, stay on social media or drink alcohol as these are all contributors to raising your cortisol levels. You may not feel stressed, but such factors are limiting your body?s ability to unwind.

All of the above hormonal changes affect our natural sleep/wake cycle, known as our circadian rhythm. Maintaining a consistent balance with these will dramatically affect how you perform and live each day.

Circadian Rhythm:

Researchers have stated that our poor sleeping habits are negatively affecting our long-term health and not getting at least 7 hours a night can reduce our chances of living a long and healthy life and can dramatically speed up the aging process. In fact, studies have shown a strong link between sleep deprivation and diseases such as cancer and Alzheimer’s disease.

Our busy schedules have not helped matters. Most of us are up before the sun rises and are arriving home as it gets dark. On top of that, we are constantly surrounded by artificial light which again makes it more difficult for our bodies to switch off. This affects our circadian rhythm which is basically our 24-hour internal clock that is running in the background of our brains and cycles between sleepiness and alertness at regular intervals. It’s also known as our sleep/wake cycle.

As night approaches, our eyes send a signal to the hypothalamus, a small region at the base of the brain, to let us know that it is time to feel tired. Our brain then lets our body know that it is time to release melatonin, thus making us tired. This is why we feel tired at night as our circadian rhythm tends to coincide with the cycle of daytime and night-time. This is also why people who do shift work find it so hard to sleep during the day and stay awake at night.

A dip in energy for most adults usually occurs just after lunch (between 1 and 3 pm) due to their circadian rhythm. With regular quality sleep, you will find that you won?t feel the dips and rises as much. However, if you are sleep deprived, like most, you will notice bigger swings of alertness and sleepiness. Going to bed and getting up around the same time each day ? including at the weekend – will help with your circadian rhythm. You may have noticed that you are out of sorts and lacking energy when you break your sleeping pattern especially when things such as jet lag or a social event disrupt your regular sleeping routine. Have you ever been more tired at the weekend even though you probably have had more sleep? That?s the break in your circadian rhythm at play. My advice here is to try to keep your bedtime routine as regular as possible especially if you are someone who struggles to get a good night sleep.

It is important to understand that being underslept is creating an imbalance in your hormones and as such is leaving your body in a stressed state. When your body is in a stressed state, it can?t focus its attention on other things such as burning fat or building muscle.  Your energy and productivity levels at work and in training are affected and your hunger levels will be all over the place. My advice is to develop a nighttime routine to restore your sleep pattern.

Here are some of my top tips for a strong sleep pattern:
  1. Regularity: Try to go to bed and get up at the same time even at weekends.
  • Darkness: Reduce exposure to artificial light in the evening. Invest in some blackout blinds and put the IPad, phone, and laptop away an hour before bed. Another option here is to invest in a pair of blue light blocking glasses, which will block the artificial blue wavelengths that make your body think that it is still daylight. Even switching off half of the lights in the house an hour before bed will help increase melatonin levels.
  • Keep it cool: Your body needs to drop 2-3 degrees Fahrenheit to initiate sleep. It is much easier to fall asleep when you are colder. Reduce the room temperature in your room to make it nice and chilly. Once you jump into your warm bed, you will drift off pretty quickly.
  •  Avoid Caffeine: Avoid coffee and other stimulants after 3 pm to help your body and mind unwind.
  • Write out a to-do list or write in a journal before bed to help the brain relax and not think about what is happening the following day.

By even adopting 1 or 2 of the above tips, your sleep quality may improve dramatically. Give them a go, develop a solid nighttime routine and experience immediate improvements in your fitness, energy, mood, and productivity.


Walker, Mathew. ?Why we sleep.? 2017.

Leproult, Rachel and Van Cauter, Eve. Role of Sleep and Sleep Loss in Hormonal Release and Metabolism. 2009.

Stevenson, Shawn. Sleep Smarter 21 Essential Strategies to Sleep Your Way to a Better Body, Better Health, and Bigger Success. 2016.

Youngstedt SD, O’Connor PJ, Dishman RK. The effects of acute exercise on sleep: a quantitative synthesis. Sleep. 1997;20:203?214. 

Luyster FS, Strollo PJ, Jr, Zee PC, Walsh JK. Sleep: a health imperative. Sleep. 2012;35:727?734


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I’m Kieran McMahon, founder of KMFitness

My mission is to help men achieve world-class body composition and fitness results and teach them how to retain these results for life.

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