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Sleep & Disease - What you need to know!

Sleep can be thought of as an Archimedes lever or a master control mechanism. When you pull the sleep lever for good or bad it directly affects every physiological and psychological system, alters our adherence to all other pillars of health and ultimately significantly contributes to our risk of all major diseases including cancer, heart disease, dementia, obesity, diabetes, depression and autoimmune disease.

Here’s How:


  • We alway have tiny cancers in our bodies. Most of them never survive because our immune system targets them and kills them before they grow or metastasise (spread to other parts of body)

  • When we lose sleep we down-regulate our immune system making it not as effective. And it doesn’t take a lot of sleep loss to make a difference.

  • One study showed a 17% reduction in our natural killer cells (the delta force or navy seals of our immune system) with one night of 4 hrs sleep.

  • Accumulate multiple nights of sleep of less than 6 hours and you will have a chronically low functioning immune system increasing cancer risk.

Heart Disease

  • Our bodies operate on an autonomous nervous system. When we are calm, relaxed and functioning optimally we are in a parasympathetic state and when we are stressed, tired and anxious we are in a sympathetic state.

  • Sleep deprivation is a significant stress on the system causing us to be in a chronically sympathetic state. The physiological response to this stress is the body being flooded with andrenaline and cortisol to excite the body and ready it for action (think running from a tiger all the time).

  • Chronic cortisol is highly correlated to contributing to atherosclerosis or plaque build up in the artery via increased inflammation. (See cortisol - glucose - insulin - fat storage - inflammation cascade below). So risk of heart attack and stroke is significantly increased.

  • One animal study showed a 50% increase in plaque build up when accounting for all other variables from just 3mths of sleep deprivation.

  • In a study of 1.6 billion people (every country that has day light savings) they have also extrapolated that there is a 24% increase in heart attacks the day after people lose one hour sleep and a 21% decrease in heart attacks when they get the hour back!


  • The links to poor sleep and dementia are now very well associated.

  • It is no coincidence that dementia happens after 60yrs old in the majority of cases and that sleep quality & quantity also drops away as we get past 60. It is one of the observations that for the most part still baffles researchers.

  • The first thing is that we see that with insufficient sleep, you get increases in oxidative stress and that leads to a whole cascade of events that lead to neuronal death. This simply means reduced brain cells to work with & reduced neural activity (talking to each other).

  • A huge potential link for dementia was found in 2012 with the discovery of the glymphatic system. It turns out the brain has its own very effective and very necessary garbage disposal or cleaning system.

  • This is a Sanitation system that kicks in when in deep sleep and glial cells shrink up to 200% in size making room for cerebral spinal fluid to fill the brain and wash out “metabolic detritus” of wakefulness

  • The glymphatic system occurs in deep sleep which is primarily in the first 2 hours of sleep and mostly prominent in the 10pm-12pm period (though not always) so when you get poor sleep or even very late sleep you miss the important cleaning system.

  • It has been thought for some years that β-amyloid was the core protein leading to Alzheimer’s formation or at the very least escalating Alzheimer’s risk.

  • This fits well with sleep studies where subjects had their non REM deep sleep taken away by playing auditory tones for one single night and you can see significant increase in circulating levels of amyloid and tau the next day. They still get 8 hours total but their “sewage system” never kicks into gear to clear those proteins out

  • The role of B-amyloid in causing alzheimers has now been seriously challenged as autopsies on severe dementia brains are showing little B-amyloid build up whilst others with high levels of B-amyloid have had no signs of dementia or alzheimers.

  • It is being postulated that B-amyloid is not a cause of dementia but a protective accumulation that occurs due to inflammation and insulin resistance in the brain! But more study is as always needed.

Insulin Resistance & Type II Diabetes

  • Keeping your blood sugar in check requires two primary things to happen.

  • Firstly your pancreas has to receive the signal that sugar is present to instigate the release of insulin which acts to shuttle the glucose in the blood stream into the muscle cells.

  • Secondly the glucose molecules have to be sensitive to the insulin signal to enable them to be taken up into muscle cells.

  • Unfortunately sleep deprivation has a double edge sword. It acts to dampen the signal to the pancreas to release insulin whilst at the same time decreasing the sensitivity of glucose molecules.

  • The end result is that blood sugar stays elevated leading to insulin resistance and on to type II diabetes!


Sleep deprivation & weight gain is now clinically proven. Heres why:

A) It increases hunger hormone ghrelin which evolutionarily designed to make you hungry and seek out food.

B) It decreases your satiety (fullness) hormone leptin so you don’t get full or satisfied as easily.

C) It activates primal parts of your brain (subconsciously) that increase your desire for sugar, fat and high calories foods. You don’t crave lettuce when tired!

D) It decreases your will power and motivation to exercise. You feel tired so the thought of expending energy becomes less attractive!

  • The net result of the factors above has been repeatedly proven in studies to result in sleep deprived subjects eating an extra 300 more calories per day than their standard diet. This equates to almost 14 kilogram of fat gain per year!

And it gets worse because sleep deprivation activates survival mechanisms that do the following:

  • Increases production of cortisol which floods insulin into the system and insulin is the gate keeper of cells with the primary roll of storing fat for energy (on a rainy day). So we not only eat more but we store more of this extra energy as fat and not release fat to be burnt as energy.

  • And if you are restricting calories on a diet but not getting enough sleep it is shown that 60% of the weight loss will come from lean muscle mass and not fat stores because your fat cells are ‘stingy’ at giving up their fat stores. Again they are in survival mode. So you end up losing far more metabolically active lean muscle mass (that would normally help you keep metabolism stimulated and keep the weight off) then i you were dieting but having good sleep and low stress.


  • Sleep deprivation and gut health & microbiome diversity & richness is also being increasingly linked to mild depression.

  • Up to 95% of serotonin is produced by good gut bacteria in your gut. Serotonin is the principle neurotransmitter associated with mood.

  • Poor sleep leads to poor food choices which mean we have a high sugar nutrient poor diet. This results in a gut microbiome in which the good bacteria is being killed off from sugar & artificial chemical ‘poisoning’, good bacteria are not being consumed (added) through probiotic rich foods and ‘fed’ by prebiotic food and the bad bacteria proliferate.

  • The result is the the metabolites that lead to the production of neurotransmitters such as serotonin and dopamine are not produced as effectively.

  • Depression and sleep are very connected and it is imperative you work with a professional on any anxiety or depression matter to find the best course of action for you.

Autoimmune Disease

  • Sleep deficit increases production of zonulin which is shown to increase leaky gut. Leaky gut means participle from our intestinal tract get into our blood stream. This cause the immune system to attack these foreign particles leading to chronic inflammation.

  • This inflammation is at the heart of many known autoimmune diseases where the body is attacking healthy cells. Rheumatoid Arthritis, Hashimoto’s thyroid, multiple sclerosis, celiac, chrones and many gut issues are caused by inflammation originating from leaky gut.

Just in cased you missed it… getting sleep, ideally 7hrs average per night at the same times (ideally 10pm-6am), is kind of good for you!

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