Importance Of Sleep

May 18, 2020 | Health & Fitness Lifestyle

Many of us work hard perfecting our diet and training programs in order to get the best results. But one main component that I often see neglected is sleep.

Think about it like this: You can get by eating not great and not exercising. You might not feel your most optimal but you still feel relatively good and functional. Now think about how you feel if you’ve had a couple night’s bad sleep or if you’ve ever pulled an all nighter. You feel like absolute garbage.

Sleep has a huge impact on our overall well being. But how does sleep affect things like hunger and body composition? Keep reading. The answer might surprise you.



  • On average, adults sleep about 7 hours per night

  • Women sleep more than men

  • Obese individuals sleep less than non-obese individuals



A 2005 study(2) showed that adults between the ages of 32 and 49 with a sleep duration less than 7 hours were more likely to be obese than adults who slept 7 or more hours each night.

This suggests that obesity may be in some part due to a decrease in the number of hours we sleep every night. And let’s be real, between smartphones and binge watching Netflix, there are many more distractions to keep us from going to bed early compared to 20 years ago.

Even more spooky, another study(3) showed that children at the age of 7 were more likely to be obese if they didn’t get enough sleep.

Although, I want to make it clear that it is uncertain if poor sleep is a cause or a result of obesity. On one hand, lack of sleep may disrupt hunger regulation hormones which may lead to obesity. On the other, obesity can also cause sleep issues such as sleep apnea. Most likely it’s a bit of both.

There are a few reasons that lack of sleep may lead to body fat gain(4,5):

  • Increased cortisol

  • Decreased in leptin (satiety hormone, i.e. you don’t feel full as easily)

  • Lowered thyroid stimulating hormone (TSH)

  • Decreased growth hormone (GH)

  • Slow insulin response


All of these together can lead to the perfect storm to increase body fat.

There is one particular dot point I want to look at more closely which I think is one of the main contributors and that is the decrease in leptin. One study(6) took 12 healthy young men and had them sleep for 4 hours a night, two nights in a row with no napping. The result was lower leptin levels and higher ghrelin levels. Ghrelin is your hunger stimulating hormone. This combo meant more hunger, and an increase in cravings, especially for calorie dense foods like sweets and baked goods.

In practice, if your sleep is shit, you’re going to have a harder time sticking to a healthy diet.

Not only does lack of sleep impact body composition, but it can increase your risk for cardiovascular issues and diabetes. Not to mention being sleep deprived makes us cranky and lowers our ability to think clearly.



You might have heard of something called the circadian rhythm before. This is controlled by the suprachiasmatic nucleus (SCN) which is influenced by our exposure to light and dark.

Many of our hormones such as GH, TSH, melatonin, and testosterone have a regular cycle that is associated with our circadian rhythm.

Creating a regular sleep routine (going to sleep and waking up at the same time each day) can cue your SCN. This allows for a deeper, more regular sleep pattern and better hormone regulation.



There are five sleep stages that occur. Stages one and two are generally lighter sleep while stages three and four are when deep sleep occurs. It takes about 90 minutes to complete a cycle of all stages

It’s these second two stages that I want to emphasize.

Stages three and four are where GH is created. GH is responsible for both physical and mental restoration (think muscle repair/growth and mental clarity). As an athlete this is key for recovery. If multiple 90 minute cycles do not occur, GH secretion is diminished and you will wake up feeling unrested and not recovered from training (5).

Not only will you feel like trash but your lack of GH will inhibit your ability to perform in the gym.



If at any point you’ve been reading this and a little lightbulb has gone off, you might need to fix your sleep.

As stated before, now more than ever, we live in a world of distractions. Most of the time, we simply do not make sleep more important than binge watching Netflix or going down a conspiracy theory rabbit hole on YouTube (anyone else been there?).

Step one is to prioritize sleep and protect your sleep time like your life depends on it (because it kind of does).

Second, make sure you are practicing good sleep hygiene:

  • Consistent bedtime and wake up time. I hate to be the one to burst the bubble but staying up late and sleeping in on the weekend can mess up your entire sleep for the week.

  • Keep the room dark. This will tell your SCN that it’s sleepy time.

  • Keep the room quiet.

  • Develop a nighttime routine. This should be something relaxing that you do every night. This prepares your brain for sleep. Avoid too much TV, phone, tablet, computer time as this can disrupt your quality of sleep.

  • The room should be kept relatively cool, between 18-22 ℃ (65-72 ℉)

  • Avoid caffeine in the latter part of your day.

  • Get some exercise! Going to the gym isn’t just for getting stronger and looking jacked, it can also help you sleep.



  1. https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/486346

  2. https://www.ncbi.nlm.nih.gov/pubmed/16295214

  3. https://pdfs.semanticscholar.org/99e3/082fc838137a34fd38002f56883e0a6cf5a3.pdf

  4. http://www.oliverfinlay.com/assets/pdf/spiegel,%20leproult,%20cauter%20%281999%29%20impact%20of%20sleep%20debt%20on%20metabolic%20&%20endocrine%20function.pdf

  5. https://www.ncbi.nlm.nih.gov/pubmed/14871884

  6. https://www.acpjournals.org/doi/10.7326/0003-4819-141-11-200412070-00008?resultClick=3&