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Sleep Deprivation: THREE Consequences

The way we view the struggles, conditions and diseases of the modern world is slowly beginning to change. You (and your doctor) may be under the impression that poor sleep is a result of stress, excess weight or even an underlying disease. Otherwise, you may not even be aware that you are struggling with sleep because tiredness has become your normality. As a result, you have prioritised factors like excess weight as the major player/s that need to be taken down, while quietly assuming the frivolous side effect of poor sleep will somehow fix itself along the way. However, are you also that same person who is religious in following the best nutrition and exercise advice only to be left dangling further down the black hole of disappointment? Maybe it’s time to juggle your priorities because there is one screaming factor that could be responsible for it all that is never getting addressed – sleep. Here’s three reasons why resolving sleep issues could help you reach those ceaseless health goals you’ve been tirelessly chasing.


1. Increased Appetite

A poor sleep (generally less than 4 hours) results in immediate reduced blood levels of the hormone leptin, coinciding with increased levels of its counterpart hormone, ghrelin. This pattern is also found in chronic sleep deprivation whereby habitual sleep is less than 7 hours each night. These hormones may sound like characters from a children’s movie (or maybe a wild dream) but they are two of the most important regulators of appetite and may just be your biggest barriers to losing or even maintaining body weight. In simplest terms, leptin is our “satiety hormone” – it tells us when we are full. Ghrelin on the other hand is our “hunger hormone” which as you guessed, signals our body to go eat something. These hormones work together to regulate energy homeostasis. However, just like so many other elegant mechanistic pathways residing within us, this synergy has been adulterated by the internal and external pressures of our modern lifestyles. Just one night of poor sleep is enough to send your appetite through the roof! Your natural instinct is to quench this irritating feeling so you start eating. But whether your choice of food is desirable from a health perspective or not, there is a latent problem working against you – your body doesn’t know when to stop. This deregulation makes it extremely difficult to stick to any healthy eating regime, even with the strongest of willpowers. Keep in mind that there are many reasons leptin may be undesirably low and ghrelin may be high, or maybe it is just that these signals are no longer being heard by our bodies as resistance comes into play.

2. Sleep Stress Cycle

It is a well-accepted ideology that high cortisol levels are reflective of stress, whether it is stress from a broken relationship, excessive exercise or stress from unmanageable workloads. It is also well-accepted that this stress can interfere with the goal of a restful sleep. However, what tends to be less understood is that sleep deprivation itself is a major player in driving cortisol up so high that our body is stuck in a constant state of “fight”. As a result, we are the first generation of humans that are struggling with our own inherent physiological functions. Night after night, too many of us are being forced to lay awake, still and silent in our own beds. As each hour passes, another hour of restoration is forfeited and we become even more vulnerable to the vicious demon that is sleep stress.

If the thought of going to sleep causes angst or tension within you; if it is something you find yourself ‘putting off’ as daylight creeps away, then it is highly likely that you are suffering from sleep stress. Our bodies are extremely resilient. The more sleep we miss out on, the more adapted to running on no sleep we become. Your body simply reprioritises; directing energy away from regenerative processes toward more immediate demands, like the production of adrenalin. Adrenalin is powerful and can give even the most chronically sleep deprived person a false sense of energy because the world is not going to stop second to your lousy sleep. So with forces like cortisol preventing you from getting to sleep or staying asleep for that matter, and equally as strong forces like adrenalin keeping you buzzing throughout the day – where does that leave your health?

You may think that you are coping because you are still ticking tasks off the list every day, but ask yourself this? Are you present in your own life or are you just doing things to get them done? Are you enjoying the journey each day brings or are you always focused on reaching a goal that only seems to drift further and further away? As psychological as this all seems, the answer could simply be that you are not getting enough sleep and it is this deprivation (what we call sleep debt), whether it be acute or chronic, that is driving the stress and hollowness you are experiencing day to day.

3. High Blood Sugars and Insulin Resistance

So apart from fuelling sleep stress, what is another consequence of cortisol that has direct effects on our weight and metabolic health? Well, when blood cortisol levels are high our body increases the production of glucose (blood sugar) so that our muscles have access to an immediate source of fuel just in case we need to run for our lives from a hungry tiger. But when was the last time you had to worry about sprinting from a deadly mammal? In our modern scenario there is no hungry tiger; there is nothing to sprint from, yet there is still all this excess glucose hanging around and we have to do something with it. So just like when we eat food that contains carbohydrate, the hormone insulin is produced to safely shuttle glucose from the blood into our cells and store it away, most likely as fat. Let’s just take a step back and acknowledge this:

- Sleep deprivation increases blood cortisol and this state of arousal is accompanied by increased blood glucose

- Failure to utilise this immediate fuel sources means that it is tucked away in our muscle and fat cells for a rainy day

The point? Body fat can increase without a single mention of a Calorie. Now of course this is overly simplistic and one night of poor sleep is not going to see you roll out of bed the next day with a muffin-top that wasn’t there before. But chronic sleep deprivation fosters a prolonging of these mechanisms and a bit of extra pudge will be the least of your worries.

Let’s get back to understanding how our body handles the excess glucose resulting from high cortisol. Initially, additional insulin is produced so that the glucose can be rushed out of the blood in a timely manner – protecting cells from damage. Insulin wears the halo in this sense, and there is no doubt that we could not live without it. However, insulin is no angel and can be more accurately described as the “fat storage hormone” because when it is around, your body is predisposed to store whatever you eat as fat. Insulin also prevents our bodies from tapping into our stored body fat reserves to use as energy if we dare needed (or wanted) to!

Unfortunately, most clinicians assume that if blood glucose is within the normal range then a person is “healthy” and creeping insulin levels are overlooked. Over time, the body builds up a resistance to insulin and our signalling mechanisms become sluggish and tired – just like you. What has just been described is the aetiology of insulin resistance and essentially, type 2 diabetes. Ultimately, the following question is raised: how many cases of diabetes are simply a cruel byproduct of chronic sleep deprivation?


A good night’s sleep is one of the most valuable assets when it comes to optimising health and it must be prioritised by YOU. The purpose of this article is to help people identify the link between sleep, weight and health. It is important to consult with a qualified health professional who can help you assess your sleep quality and provide individualised strategies that aim to effectively improve such.


  1. Franklin J. Obesity Management. Medical Nutrition Lecture Series; University of Sydney: Royal Prince Alfred Hospital Metabolism and Obesity Services; 2016.

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

  3. Knutson KL, Spiegel K, Penev P, Van Cauter E. The Metabolic Consequences of Sleep Deprivation. Sleep medicine reviews. 2007;11(3):163-78.

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