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 centres 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?
“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”
Sleep we know has huge impacts on our oxidative stress. Allow this stress to continue for any length of time it then impacts 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 its 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 Alzheimers. 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 4 tenets:
1) Regularity, i.e 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 Alzheimers or dementia later in life.
When you consider that many older people develop cardiovascular disorders, and one of the side effects of poor sleep is cardiovascular disorders, this in turn has an impact upon the brain and its ability to dispose of glucose or blood sugars.
Most people do not realise that a good eight hours sleep is one of the best methods to control blood pressure.
So, let’s 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 do not forget
Stage 2 of non-REM
- Refreshes and prepares your brain for future learning and memory
- Sleepless spindles exponentially increase towards the end of the night, so you get most of your spindle-rich sleep in the last two hours of the night
- 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?
- Increased mental health issues: anxiety, depression, suicidality
- Could say that an anxious person can't sleep because of anxiety, or lack of sleep causes anxiety: goes both ways
- Sleep is emotional first aid
- In young teens, strongest predictor of suicidal ideation, attempts and completion is insufficient sleep
- REM sleep seems to recalibrate emotional networks in brain (middle part of pre-fontal cortex and amygdala)
Learning from a sleep deprived child
- When a 4-year-old misses one nap, you can see change in behaviour
- Parents 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 stigmatise it with ideas of laziness and sloth
Sleep has declined over the last 100 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. Nowadays, 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.
Guinness has banned trying to set record for sleep deprivation (the record may have been up to 24 days), however because it is so dangerous (cancer, mental health, CVD, metabolic syndrome, suicidality), the record was banned. Which should be evidence enough that sleep deprivation in humans 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? – DO NOT - Here’s Why
Needing sleep has been given a bad wrap, even stigmatized and laziness.
- Margaret Thatcher and Ronald Reagan famously proclaimed the uselessness 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
- 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 have almost never seen before