I'm not a sleep scientist, but I've recently read a book by Matthew Walker who runs Harvard's sleep research laboratory and I wanted to share a whole bunch of important, useful and interesting details about sleep.
What is it, what it isn't, why is it important and how it affects us.
First of all, when did sleep appear? It seems that sleep appeared shortly after life itself on the planet. Every organism sleeps, certainly every animal does and did so for a very long time even evolutionarily speaking
Nature does not spend huge amounts of effort on pointless things. Sleep serves absolutely vital functions, and if sleep is disrupted we suffer serious physiological problems
Sleep isn't a single thing. It is a combination of a multitude of different processes 2/14
Generally speaking: regular, good quality sleep of sufficient length (8h) is the single biggest improvement you can do for your health
Sleeping 6-7h or less demolishes your immune system, doubles the risk of cancer, contributes to an increased risk of developing Alzheimer's later in life, increases your chance of developing cardiovascular diseases, contributes to most major psychiatric conditions, greatly reduces your ability to learn to percieve emotions and make logical decisions
Research shows that people shift their baselines and when exposed to long-term lack of sufficient sleep, they have no idea how badly they perform compared to their healthy baseline.
"I feel fine on 6h of sleep" is a myth. There are no humans who need less sleep than others and can still function as well as when having adequate sleep.
People just get used to their decreased state of functioning.
Caffeine: caffeine is bad, VERY bad.
It is something called an adenosine blocker, adenosine being one of the chemicals in the body signaling sleep.
Caffeine has a half-life of 5-7h, but affects sleep duration and quality even after 16h.
Coffee, tea, energy drinks, chocolate, certain medications and even ice cream contains or can contain caffeine.
How do you tell if you're getting enough sleep?
1. If waking up in the morning, could you fall asleep again around 10-11am?
2. Can you function without caffeine before noon?
If you answered yes to either, then you probably need more sleep or better quality sleep.
If you can't sleep well long-term (>3 months), go and see a doctor and get a referral to a sleep specialist!
Do NOT take sleeping pills, they do not work for the same reason alcohol is bad for your sleep: they are technically sedatives that ehm sedate you.
They produce effects more akin to a coma than to real refreshing sleep with it's NREM stages and REM cycles and will leave you worse off than not taking them.
Lack of sleep leads to more car accidents than drunk driving and other kinds of drugs combined.
By sleep loss I mean, compared to 8h of sleep, sleeping 6-7h you have 1.3x the chance to have an accident, 5-6h: 1.9, 4-5h: 4.3x all the way up to <4h and a staggering 11.5 times the chance to be involved in a car accident!
After spending around 16h awake, you need to start sleeping. Without that, your cognitive functions decline rapidly.
So WHEN should you sleep?
There are differences in our circadian rhythm, so early-risers and night owls exist. The key is consistency though, the circadian rhythm can adjust up to an hour a day to changes in your sleep schedules, so varying it more than that day to day is not good for getting quality sleep.
Teenagers do need more sleep than adults by around an hour and their circadian rhythm is tuned for a later awakening than for adults. Let teens sleep.
Btw, people in the Mediterranean do it right.
That food-coma after lunch? It's not food coma. Evolutionarily we're supposed to have a 30-60min nap after lunch and this is why you're feeling sleepy around that time.
The siesta exists for a reason.
Also, older people need just as much sleep as younger adults. Older people might have more trouble falling asleep or staying asleep though and that affects their health quite substantially.
So what can you do to actually sleep better?
If you do only one thing, then it's to keep a regular, consistent schedule of at least 8h of sleep at the same times, including on the weekends
This is what you can do though:
1. Avoid caffeine & nicotine completely
2. Avoid alcohol before bed
3. Have lots of light in the morning, avoid bright lights after sunset. Blue light is bad, so reduce mobile/screen time before bed and/or use night mode for them 11/14
4. Do not exercise 2-3h before going to bed and have a cooler (around 18.5°C) bedroom.
In order to initiate sleep your core body temperature needs to drop by a degree, this is why exercise and a less heated bedroom is optimal.
5. You can have a warm bath though before sleep.
It dilates your blood vessels that result in more heat being radiated from your core therefor your temperature drops faster, allowing you to fall asleep faster.
Talking about doctors, never trust a sleep-deprived doctor to diagnose you or operate on you.
A doctor who's been awake for 22 hours has their performance impaired to the same level of someone being legally drunk
The lack of sleep on a societal level is an _epidemic_, resulting in so many negative effects that I had to compress and simplify a lot even in this long tootchain. If you'd like to boost this thread, boost the last one though so it correctly propagates please.
If you're interested in more about sleep, read Matthew Walker's book: https://en.wikipedia.org/wiki/Why_We_Sleep
It's really readable, is fascinating, scary, interesting and I think the only book on the planet that considers it a success if it puts you to sleep.
If you'd like to ask something that I might know the answer to, feel free - I'd be happy to try and reply. Perhaps the next day, as I'll soon head to get my own 8 hours of sleep.
Bonus: you don’t sleep to conserve energy.
Sleep is an intensive process and your brain goes through a cleaning/toxic substance removal process, high speed memory transfers from short to longer term memory, does a bunch of planning via dreams, consolidates experiences and emotional state.
And that’s just the brain part.
@szbalint that's a dissertation, not a toot...😅
re: sleep science
@szbalint My own experience with hypersomnia and fatigue, still mostly unresolved, has led me to be pretty jaded about sleep specialists.
Yeah, they can diagnose sleep apnea, narcolepsy, some other things. (And those are really important to check for! I don't want to discourage people from getting checked out for those!) But beyond that, I feel like they know basically nothing about how to address these symptoms.
I guess it's not their fault, just a lack of science. :-/
@szbalint Is there a typo here? It doesn't seem like saying 'yes, I can function without caffiene' would be a sign that I need more sleep.
@jessmahler Yes, there is a typo there and it's a quite bad one :( That sentence should have read
"Do you need caffeine to function before noon?"
> People just get used to their decreased state of functioning.
I really can't tell you how grateful I am to you for this exact phrasing of this exact thing
Exclusive or something