I have long been a fan of Peter Attia MD and his wonderful podcast – The Drive.  However recently he did a series of three podcasts with the extraordinary Matthew Walker Phd on sleep.  The information was incredible and here I have taken a lot of the highlights and shared them.  Also at the bottom you will find links to the podcasts themselves and I implore everyone to listen to them in full, as the information contained within could literally be life changing.

The Dangers of Not Sleeping

Sleep is one of those things we take for granted. Every living creature has to sleep for a required amount of time, and yet we are the only species on the planet that actively chooses to be sleep deprived.

Approximately one third of our lives will be spent in a sleep state and yet we know so little about it.  We know far more about our other fundamental needs such as eating, drinking, and our procreation.  However the sleeping portion of our lives, we still have so much to learn and understand. 

Dr Matthew Walker Phd, observed when studying the brainwave patterns of people with dementia that different pathologies seemed to affect different sleep centers in the brain, and from these observations a hypothesis started to occur that perhaps sleep disruption could be a biomarker of dementia or maybe an underlying cause?

He comments:

“Based on the weight of the data we have, the evidence, I think it is causal.  I think that sleep, at this stage, may be one of the most significant lifestyle factors that determine’s your risk ratio for Alzheimer’s disease.  I feel the causal evidence for that now in humans and animals is strong enough to make that statement.  And I don’t make that statement lightly”

Alzheimer’s

Sleep we know has huge impacts on our oxidative stress.  Allow this stress to continue for any length of time it then impact a whole raft of other areas including neuronal death.

Our hippocampus which is responsible for our memories is the first area to become damaged in Alzheimer’s hence we become forgetful.

In 2012, Rochester University discovered that the brain has it’s own detox system known as the glymphatic system using the glial cells. This system could be likened to our lymphatic system.

This system only operates when we enjoy deep sleep and our glial cells reduce in size by up to 200% allowing the cerebral spinal fluid to fill the brain space and clean out the rubbish, which has been accumulated during the waking hours.

How does this relate to Alzheimer’s disease?  Well one of the waste products regularly washed away is B-Amyloid, which is a core protein that builds up in those affected by Alzheimer’s.

PET scans of amyloid build up in the brain show a marked difference in those who sleep 7 hours or more as opposed to those who have less than 7 hours sleep.  For further confirmation of this phenomena rats were deprived of sleep and were also given controlled bouts of fragmented sleep.  This resulted in an immediate build up of B-amyloid.

The significance is such that when you deprive sleep from a human for just one night there is a marked increase in the amount of circulating amyloid and tau proteins the next day.

There is now strong evidence to suggest that long periods of sleep insufficiency can be a strong predictor of a risk of Alzheimer’s.   Long term lack of sleep means increased build up of tau proteins and amyloid, and an inability of the Glial cells to do their job at night of detoxing and cleansing the brain.

Sleep Requires Four Tenants

  1. Regularity, ie consistent bed time
  2. Continuity of good restful sleep (with few waking periods)
  3. Quantity (Full stages of sleep in the correct quantities)
  4. Quality (how good is the electrical signature) hugely affected by caffeine, alcohol.

Subjective questionnaires looking at the sleep quality over different decades of people’s lives is now looking to be a very good indicator as to the likelihood or Alzheimer’s or dementia later in life.

When you consider that many older people develop cardiovascular disorders, and one of the side affects of poor sleep is cardiovascular disorders, this in turn has an impact upon the brain and it’s ability to dispose of glucose or blood sugars.

Most people do not realize that a good eight hours sleep is one of the best methods to control blood pressure.

So lets take a closer look at the mechanics of sleep.

You have Non-REM sleep, which has four stages, known as 1,2.3 and 4.

Stages 3 and 4 are the very deep restorative stages.

Stages 1 and 2 are the lighter stages of sleep.

Then you have Rem Sleep (REM stands for Rapid Eye Movement, which comes from horizontal shifting eye movements).

REM sleep occurs every 90 minutes as your brain cycles between both REM and Non REM.

Memory and Sleep and the Risk of Insufficient REM Sleep

Deep non-REM sleep (stages 3 & 4)

  • Protects new learning from the day before
  • “You need sleep after learning to essentially hit the save button on new memories so that you don’t forget.”

Stage 2 of non-REM

  • Refreshes and prepares your brain for future learning and memory
  • Sleep spindles exponentially increase towards the end of the night, so you get most of your sleep spindle-rich sleep in the last two hours of the night
  • So the stage 2 non-REM sleep happens mostly in the second half of night and prepares your brain to learn
  • “The more of those sleep spindles that you have, the greater refreshment of your memory and coding ability.”

What’s the biggest detriment that people face clinically with the reduction of REM?

Learning from a sleep deprived child

  • When a 4-year-old misses one nap, you can see change in behavior
  • Parent’s of young kids seem to know that bad sleep equals bad mood and emotional reactivity the next day (amygdala)
  • But shortly afterwards, we abandon the notion that sleep is essential and non-negotiable, and we stigmatize it with idea of laziness and sloth

 Sleep has declined over the last100 years.  In years gone by, people got up with the sun and went to bed when the sun went down.    This meant on average people enjoyed a good solid 8 hours sleep.  Now a days people on average get between six and seven hours sleep which is a 20 – 25% reduction.  This can lead to serious health consequences; sleep is absolutely the foundation of your health.   Depriving someone of sleep is the fastest way to have a detrimental impact on their health.

PET scans of amyloid build up in the brain show a marked difference in those who sleep 7 hours or more as opposed to those who have less than 7 hours sleep.  For further confirmation of this phenomena rats were deprived of sleep and were also given controlled bouts of fragmented sleep.  This resulted in an immediate build up of B-amyloid.

The significance is such that when you deprive sleep from a human for just one night there is a marked increase in the amount of circulating amyloid and tau proteins the next day.

There is now strong evidence to suggest that long periods of sleep insufficiency can be a strong predictor of a risk of Alzheimer’s.   Long term lack of sleep means increased build up of tau proteins and amyloid, and an inability of the Glial cells to do their job at night of detoxing and cleansing the brain.

Sleep Requires Four Tenants

  1. Regularity, ie consistent bed time
  2. Continuity of good restful sleep (with few waking periods)
  3. Quantity (Full stages of sleep in the correct quantities)
  4. Quality (how good is the electrical signature) hugely affected by caffeine, alcohol.

Subjective questionnaires looking at the sleep quality over different decades of people’s lives is now looking to be a very good indicator as to the likelihood or Alzheimer’s or dementia later in life.

When you consider that many older people develop cardiovascular disorders, and one of the side affects of poor sleep is cardiovascular disorders, this in turn has an impact upon the brain and it’s ability to dispose of glucose or blood sugars.

Most people do not realize that a good eight hours sleep is one of the best methods to control blood pressure.

So lets take a closer look at the mechanics of sleep.

You have Non-REM sleep, which has four stages, known as 1,2.3 and 4.

Stages 3 and 4 are the very deep restorative stages.

Stages 1 and 2 are the lighter stages of sleep.

Then you have Rem Sleep (REM stands for Rapid Eye Movement, which comes from horizontal shifting eye movements).

REM sleep occurs every 90 minutes as your brain cycles between both REM and Non REM.

Which should be evidence enough that sleep deprivation in human’s can be deadly.

In 1983 they deprived rats of sleep until they died, and they died 20% sooner than they did from starvation.

Ever Driven In A Drowsy State Behind The Wheel? – Don’t Here’s Why

Needing sleep has been given a bad wrap even stigmatized and laziness.

  • Margaret Thatcher and Ronald Reagan famously proclaimed the usefulness of sleep
  • Sleep is for the weak, sleep when you’re dead, etc.
  • Would proudly say they only needed 4-5 hours of sleep a night
  • With the knowledge we know now is it any wonder that both of them went on to develop Alzheimer’s disease”. Such a sad and desperate end, to two incredible people.

The single biggest reason why a lack of sleep is so frightening is that it almost certainly is the single biggest cause of chronic illness later in life such as Alzheimer’s.

The other reason, which is rarely thought about is fatal car crashes.

  • Someone who is totally sleep deprived will have a higher risk of falling asleep at the wheel of a car. The one that most folks don’t really know about but is far more common is microsleeps.  These are small lapses where the eyelid will partially close.

What is not widely known is that drowsy driving accounts for more accidents on our road than either drugs or alcohol combined.

When the eyelid partially closes, you no longer react, which is different say from a drunk driver who will generally swerve and there is generally a reaction and some breaking.

However a micro sleeping person can only be described as a projectile missile and is potentially far more fatal.

The Erosion Of Our Sleep

  • “The erosion of sleep time has hit an all-time high. We are now sleeping less than we have ever done in what seems to be the history of our species.”
  • In 1942, the average person slept 7.9 hours per night
  • Today, the average person sleeps 6 hours and 31 minutes
  • The decline has not been linear, it is accelerating
  • Essentially we have a perfect storm signalling the Collision between increasing sleep deprivation and increasing sickness and disease that we’ve almost never seen before

“There is no physiological system in the body, and there is no operation of the brain that isn’t wonderfully enhanced by sleep when you get it, or demonstrably impaired when you don’t get enough.”

Lets Take A Look At Cardiovascular Disease

There was a study: Short sleep duration and incident coronary artery calcification.  Which tracked healthy adults without signs of CVD.  What they discovered by the end of the study can only be described as alarming.  Those people getting 5 hours sleep or less had a 200 – 300% increased risk of coronary artery calcification.

Understanding the mechanism for sleep is fundamentally important here.  With a lack of sleep, the body becomes much more driven by the sympathetic nervous system (the fight or flight branch of the nervous system) and this just keeps increasing as the lack of sleep prevails.

This will cause a greater release of adrenaline, and increased spike in cortisol levels and a blunting of growth hormone.  These are all factors, which lead to atherosclerosis.

There are other considerations too.  A lack of sleep can increase blood pressure (hypertension).

Dr Michael Walker Ph.D. “If there is one central, common pathway through which we can understand almost all aspects of the deleterious impact of insufficient sleep, it is through the autonomic nervous system, and specifically an excessive leaning on the fight or flight branch of the nervous system.”

Ever Wondered Why You Have No Will Power When You Are Tired?

When you are tired it is far more difficult for the body to dispose of glucose, this is why folks have a tendancy to eat rubbish when they are tired.  The more rested you are the better your ability to make the decisions about what you eat.

There is something called fuel partitioning, which is essentially the energy balance of the body.  The checks and stops of input, output, and regulation of the body.  How much you eat and how your body uses it.  This is all hugely affected by the amount of sleep you have had.

Dieting whilst sleep deprived is not a good idea.  There is a great study which demonstrates that dieting when sleep deprived of 6 hours or less was much less effective in terms of fat loss than a well slept individual.  When you are under slept 70% of what you lose is from lean muscle mass and the body prefers to hold onto your fat.  The major reason for this is the high levels of cortisol (stress hormone) and insulin in the body.

How Does A Lack Of Sleep Affect Reproduction?

Well chaps you need to listen up:

Now for the ladies:

FSH and LH in women

  • One experiment showed:
    • Women who sleep 5-6 hrs have a 20% reduction in FSH (a critical part of the reproductive pathway)
    • They also have a 30% higher rate of abnormal menstrual cycles
  • From a reproductive standpoint, this is devastation.

Fasted state:

  • Men don’t seem to be less able to reproduce in a fasted state
  • But women do tend to be less capable of reproducing when in a fasted state (study, in rats)

What Tools Can We Use To Help Correct Sleep Issues:

Melatonin can be very useful for many people, not only can it help people to fall asleep but it also assists in the glymphatic system in cleansing the brain at night.

Blue Light blocking glasses can be very beneficial to wear in the evening.  When you go home and turn the lights on is the time to wear your blue blocking glasses.  Blue light from TV screens, computers and light bulbs sends a signal to the brain that it is midday which raises your cortisol levels and depresses your ability to create melatonin and wind down.  This can be avoided by wearing blue light blocking glasses or better still avoiding all technology for two hours before bed.

Day light is so incredibly important it helps set the circadian rhythm in the body so it knows when to keep you alert and awake and when to wind down.  Added to this sunlight itself has so many health benefits including Vitamin D3 (which is actually a hormone).

Body Temperature plays a huge role in the quality of your sleep.  People’s body temperature generally drops during sleep, which is a good thing, so sleeping in a well aired room at night can assist this.

Cancer and How To Improve Immune Function With Sleep

Cancer is a devastating diagnosis for anyone, but in order for this to occur a few things have to go wrong:

Firstly there is generally some genetic insult on the system, and secondly the insult, does not get noticed by the immune system.  (Most of the time your T Cells pick it up and address it).

How does sleep affect the immune system?

A further study by UCLA demonstrated the following: Partial sleep deprivation reduces natural killer cell activity in humans.

They took healthy adults land limited them to 4 hours sleep for one night.  They then measured their natural killer cells (which identify foreign elements like cancer cells and destroy them)

  One night of poor sleep caused 70% drop in natural killer cell activity.

Now imagine what the ramifications could be after months of insufficient sleep.

To bring the message home in an even greater way a Study using mice by David Gozal at the University of Chicago looked at mice with cancer.  One group received normal sleep, the other group had their sleep restricted.

The group with the mice whose sleep had been restricted had tumours 200% larger than the mice who slept normally.  The cancer in the sleep deprived mice had also metastasized.  So the moral of the story is ensure you get enough sleep whether you have a diagnosis or not.

What Effect Does Our Technology Have Upon Us?

Let’s take a look at iPhones, iPods’ and television usage.

  • This study suggests using an iPad before bed has negative effect on sleep⇒ 50% drop in melatonin (aka you lose 50% signal of sleep timing), and your peak melatonin will arrive 3 hours later.
  • iPod time also reduces REM time
  • Effects last 2-3 days
  • Television time doesn’t have quite the same effect, but… it does make brain associate bedroom with TV and when you start to form those maladaptive associations, it can be a trigger of insomnia and anxiety.

We have covered so much information here and the message is clear we need to sleep more.  We need to have the courage to openly acknowledge the importance of our sleep and protect it fiercely as your health and mental state in later life may well depend upon it.

Matthew Walker:  Professor of Neuroscience and Psychology at the University of California, Berkeley, USA. He is also the founder and director of the Center for Human Sleep Science.

References: 

Strongest evidence of sleep and Alzheimer’s disease risk is a remarkable discovery that the brain actually has a sewage system coined the “glymphatic system”A Paravascular Pathway Facilitates CSF Flow Through the Brain Parenchyma and the Clearance of Interstitial Solutes, Including Amyloid β (Iliff et al., 2012)

Difference in amyloid build up in people getting seven hours of sleep or less, compared to seven of hours of sleep or more:  Self-reported sleep and β-amyloid deposition in community-dwelling older adults (Spira et al., 2013)

Difference in amyloid build up in people getting seven hours of sleep or less, compared to seven of hours of sleep or more:  Self-reported sleep and β-amyloid deposition in community-dwelling older adults (Spira et al., 2013)

Sleep fragmentation in humansSleep Fragmentation and the Risk of Incident Alzheimer’s Disease and Cognitive Decline in Older Persons (Lim et al., 2013)

In a rodent model of AD, chronic pharmacological or environmental sleep disruption was associated with a more rapid accumulation of amyloid beta pathology: Amyloid-beta dynamics are regulated by orexin and the sleep-wake cycle (Kang et al., 2009)

Take deep sleep away from a human for one single night and you can see significant increase in circulating levels of amyloid and tau; “the turning point” for MatthewEffect of 1 night of total sleep deprivation on cerebrospinal fluid β-amyloid 42 in healthy middle-aged men: a randomized clinical trial. (Ooms et al., 2014)

Strongest predictor of suicide in young teens in is insufficient sleepInsufficient Sleep and Suicidality in Adolescents (Lee et al., 2013)

Guinness bans records of sleep deprivation: Watch: Here’s What Happened When a Teenager Stayed Awake For 11 Days Straight |  BBC Crew (sciencealert.com)

Total sleep deprivation of rats until death in the 1983Physiological correlates of prolonged sleep deprivation in rats. (Rechtschaffen et al., 1983)

Selectively deprived rats of non-REM or REMSleep deprivation in the rat: X. Integration and discussion of the findings. (Rechtschaffen et al., 1989)

Drowsy-driving related accidentsPrevalence of Motor Vehicle Crashes Involving Drowsy Drivers, United States, 2009-2013 | (aaafoundation.org)

Chronic sleep restriction: neurobehavioral effects of 4 hr, 6 hr, and 8 hr TIB. (Dinges et al. 1999)

Increase in heart attacks the day following daylight savings timeDaylight savings time and myocardial infarction (Sandhu et al., 2014)

Increase in car crashes day after daylight savingsImpact of daylight saving time on road traffic collision risk: a systematic review (Carey et al., 2017)

Increase in suicide attempts the day after daylight savingsSmall shifts in diurnal rhythms are associated with an increase in suicide: The effect of daylight saving (Berk et al., 2008)

Increase in coronary artery calcification by 200-300% with 5 hours of sleep or lessShort sleep duration and incident coronary artery calcification. (King et al., 2008)

Sleep deprivation and lower testosteroneEffect of 1 Week of Sleep Restriction on Testosterone Levels in Young Healthy Men (Leproult et al., 2011)

5 hours of sleep or less is linked to smaller testicle sizeSleep Duration Is Associated With Testis Size in Healthy Young Men. (Wang et al., 2018)

Men who are sleeping six hours or less will have fewer sperm and those sperm will have more deformitiesSleep duration is associated with sperm chromatin integrity among young men in Chongqing, China. (Wang et al., 2018)

Women who sleep 5-6 hrs have a 20% reduction in FSH and Women who are sleeping that little too, typically have about a 30% higher rate of abnormal menstrual cyclesRelationship between sleep and secretion of gonadotropin and ovarian hormones in women with normal cycles (Touzet et al., 2002)

Breast cancer and sleepInvestigating causal relationships between sleep traits and risk of breast cancer: a Mendelian randomization study (Richmond et al., 2018)

Prostate cancer and sleepWork schedule, sleep duration, insomnia, and risk of fatal prostate cancer. (Gapstur et al., 2014)

Colorectal cancer and sleepShort duration of sleep increases risk of colorectal adenoma (Thompson et al., 2011)

World Health Organization classifies night time shift work as a probable carcinogenNight Shift Working “A Probable Human Carcinogen” | Grace Rattue (medicalnewstoday.com)

Sleep deprivation reduces natural killer cellsPartial sleep deprivation reduces natural killer cell activity in humans. (Irwin et al., 1994)

Tumors grow more in sleep deprived miceFragmented sleep accelerates tumor growth and progression through recruitment of tumor-associated macrophages and TLR4 signaling (Hakim et al., 2014)

Matthew Walker’s article in The LancetSleep Prescription for Medicine (Matthew P Walker, 2018)

Using iPad at night can significantly affect sleep and reduce your melatoninEvening use of light-emitting eReaders negatively affects sleep, circadian timing, and next-morning alertness. (Chang et al., 2015)

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