Lack of sleep drastically affects many functions in the body, especially those of our metabolism, hormones, and immune system.  The body can usually handle an occasional poor night’s sleep, but when the problem lasts for a while and insomnia develops, major disruptions in the body occur, resulting in a huge array of health problems.  These include increased fat storage, diabetes, recurrent infections, gut issues, anxiety, depression, chronic fatigue, adrenal insufficiency, thyroid imbalance, cancer, heart disease, and more.


Other outcomes from not getting enough sleep are accidents, relationship problems, loss of work, addiction to caffeine and/or alcohol and other substances, increased risk taking due to poor judgement, and even financial hardship.

So not only does bad sleep make us feel awful and grumpy, it can cause us major life problems, and it actually stops the body from doing what it needs to – because it is during sleep that the body performs the majority of our healing, detoxifying, and regenerating.

Research has proven that sleep loss results in effects of increased ageing too. One study demonstrated that by reducing sleep from 8 hours to 4 hours per night, people showed changes that resembled the effects of old age and the early stages of diabetes – after less than one week!

Medical studies have also shown that lack of sleep actually damages the brain, causing permanent memory loss, inability to focus, poor concentration, and even a reduction of emotional intelligence.

Gene function can be disrupted too, resulting in a multitude of debilitating health conditions.

Therefore it is obvious that this wonderful thing called sleep, which is still not completely understood in the world of medicine, is probably THE most important contributing factor to good health – because of the extensive number of health areas damaged by insufficient sleep.

So let’s take a closer look at just how sleep deprivation affects metabolism and hormones.

Metabolism is the term for a whole range of chemical processes in our bodies, but generally when metabolism is referred to, it is in relation to how we convert food (calories) into energy.  When we are awake for more hours than we should be, our calorific demand becomes higher, so we eat more; due to being awake for longer (which is energy that is not necessarily ‘burned off’, and our body ‘saves’ for later when it is expecting us to be more active).

Lack of sleep also increases appetite, because a peptide secreted by our stomach called ghrelin, which tells us when we are hungry, increases when we do not have enough sleep – so we feel more hungry.

Also, the hormone leptin, which is excreted by our fat cells and tells us when we have eaten enough, decreases when we do not sleep well, so again we feel much hungrier and do not stop eating when we normally would.  Leptin also messages our thyroid gland, and a low leptin level will cause the thyroid gland to slow metabolic rate and store calories as fat.

Add all this to the fact that when we are tired we are also less likely to want to exercise, or able to exercise effectively, and this is a perfect recipe for unwanted body fat, and a road heading straight to diabetes and other major health issues!

Growth hormone production becomes low as well when we have too little sleep, which hinders tissue repair and muscle growth – something nobody wants.

Both male and female sex hormones also become low and/or unbalanced, which obviously causes numerous problems.

Other major hormonal changes from lack of sleep are extensive too, which can drastically affect our mental health.  These include our energy and mood stabilising thyroid hormones becoming unbalanced, resulting in fatigue, depression, anxiety, weight gain, etc.  Our stress hormone cortisol becomes overstimulated, making us more stressed, irritable, anxious, emotional, and likely to comfort eat.  This continual overstimulation of cortisol will eventually result in adrenal burnout (to the point where cortisol becomes severely low).  Melatonin, our sleep hormone becomes suppressed, which makes sleep more difficult, and causes forgetfulness, poor concentration, and fatigue.  Both cortisol and melatonin work in a fine balance of each other, and if one is high or low when it shouldn’t be, the other hormone soon becomes unbalanced too.  So as you can see, this explains why when we are stressed we can’t sleep, and when we can’t sleep we feel more stressed!

It is no wonder that sleep deprivation has been used as a very effective form of torture!

Therefore sleep is clearly extremely important, for both our mental and physical health.

Unfortunately though, most of us are surviving on well under the recommended 8 hours of sleep per night. So it is obvious that having good ‘sleep hygiene’ is something we all need to work on.  It is important to point out too, that despite some people feeling as though they function adequately on less sleep, this is definitely not ideal because of the time required by the body to carry out the functions it needs to while we are sleeping. Therefore, instead of burning the candle at both ends, the wise choice is to head to bed, so the body can do what is required for our health.  Sometimes it isn’t that simple though, and a night of laying awake is all that follows.

So, if you are experiencing difficulty sleeping, and possibly health problems due to sleep deprivation, please visit my blog again soon because in my next article I will be covering tips on promoting deep and restorative sleep, and how to check for possible causes of insomnia and how to resolve them effectively.

I hope you have found my information interesting and helpful.  If you would like to contact me about how I may be able to assist you with your health and fitness, you can email me at:

Bye for now,