Eli5: Why do we need to sleep so much, what happens in the body when asleep that cannot happen while normal resting or relaxing? Or is it just for the brain?
In: Biology
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In the book why we sleep the author writes that we sleep because during sleep the brain flushes out metabolites. Essentially cleaning the brain. During sleep the brain also moves memories from short term memory to long memory
We don’t really know but I like think it’s kinda like a computer. If it’s up for a whole year with no shutdown, processes and apps will eat up ram (even though they aren’t running). Shutting down your head computer is the only way to fix that
The question should be the other way around:
Why are we awake so much?
Being conscious and awake takes a lot more energy than sleeping. We have evolved to be awake just long enough to do all the things we needed to do to survive: hunt, gather, eat, mate, etc.
What’s it like to “notice” while you’re deeply asleep that you uncomfortably twisted one of your joints and then, without waking up or disturbing your consciousness, automatically adjust your sleep position to fix it?
Creatures such as [Jellyfish and bugs](https://animalhow.com/which-animals-do-not-sleep-5-species/), have such simple minds, I don’t think it’s a stretch to say that they do everything “unconsciously” — sorta “sleepwalking” 24/7 in effect.
You are thinking about this backwards. We sleep because we didn’t need to be fully alert 24/7 in order to survive. If our body could survive by sleeping all the time it would only do that. Why the hell would it wake up and walk around doing work and burning calories when it doesnt need it. It only wakes up and becomes alert because it knows it won’t survive if it stays asleep forever.
This question has a very long explanation which is answered by the book [why we sleep by Dr Matthew Walker](https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.amazon.co.uk/Why-We-Sleep-Science-Dreams/dp/0141983760&ved=2ahUKEwiw1-ntscjtAhXQVsAKHXctBnsQFjANegQIMBAB&usg=AOvVaw1cIRs7FtuFLbc6qVLTdbRS)
Seriously, every question you have about sleep including the one in this post is answered in this book. I was always a person who didn’t care about my sleep until I finished reading this book. I also HATED reading books and this was the first book I actually read by myself – I often found myself reaching for this book of I had a spare 10 minutes rather than my phone, I just thought looking at words on a page was boring… Until I saw how well written this book is.
This book isn’t just for people who are fitness conscious, this book is for ANYONE that wants to live a better quality life.
This book talks about a variety of topics surrounding sleep including: effects of chronic sleep deprivation/how technology and urban life affects our natural circadian rhythms/ effects on obesity and how adequate sleep impacts muscle building/ looking at indigenous tribes and civilisations that aren’t influenced by society and technology/mental health and cognitive health
Nobody knows yet. A lot about the brain is still unknown, which I found very fascinating and why I entered this field for a career.
There are many hypothesis but I tend to lean toward this one.
The brain functions at frequencies. We learned these frequencies with the discovery of EEG (where we monitor brain electric activity from the surface of the skull)
These frequencies change based on what a person is doing. There’s a deeper source inside the brain that generates those electrical impulses to force the entire brain to work at a certain frequency. (It’s amazing to watch by the way when we scan EEGs)
Sleep tend to provide a certain frequency that you really cannot generate in a normal day while doing normal day to day activity.
Believe it or not, turns out you actually can generate the same frequency when you meditate.
For whatever reason we still don’t know, that certain meditation/sleep frequency, has an effect to the general mental health of the individual. They allow the brain to bring balance to its dynamic function.
Now the 5 year old version explanation of that would be:
Your brain is has waves .. like a sound wave .. but they’re electric.
These waves get rough when you are awake, think, work, do math .. etc
Like when the wind hits the ocean.
If those waves don’t slow down, it can make you stress and get tired .. so you meditate and sleep, to slow down those waves and make them calm again. Like when the ocean is quiet.
So. Much. Stuff. So much. Here’s a quick overview.
Simplified, you sleep in a couple different phases: REM (Rapid Eye Movement, the dreaming phase), and NREM, often split into NREM 1 and 2/ NREM 3 and 4 (slow wave, “deep” sleep). Each of these types of sleep has a different job.
During REM sleep, all the stuff you experienced and learned during the day gets replayed over and over, along with other old memories that your brain tries to mash together, making new connections and strengthening memories. A lot of inspiration comes from dreaming, because you just can’t try out as many combinations of thoughts and ideas when you are awake. It’s extremely important for memory and brain development, like another person said. Dreaming is also very important for getting over traumatic events, as dreams will make you relive them, but a very important stress hormone in your brain is turned off, so you can process the grief and other feelings without the trauma. PTSD, by the way, is what happens when this system fails.
In NREM 1 and 2, one of the cool things that happens is that “muscle memory” is developed. Ever practiced something, got frustrated and stopped, and after sleeping on it, suddenly been able to do it? Your brain practices in your sleep. If you’re trying to learn a new skill, make sure to get enough sleep.
Deep NREM is the part where your brain reorganizes everything. Useless memories out, important memories saved and put into long-term storage. This part is extremely important for reducing anxiety and stress, as well as memory. Not only does this help you remember the things you learned from that day, it also clears up your short-term memory storage (basically like RAM) so you can start again in the morning. Don’t underestimate the difference this makes. You can’t put memories into long-term storage while awake, and you are losing them constantly as new ones replace them.
Your blood pressure also goes way down, your heart gets some TLC, your whole body gets restored. Like another user said, toxins are flushed out. One important “toxin” is so-called amyloid plaque, a mess of proteins that you produce, and that get caught in your brain, every second you are awake. These destroy your brain and memory if allowed to keep growing unchecked. The *only* way to get rid of them is to get enough high-quality sleep, every night.
These proteins are the reason older people get diseases like Alzheimer’s: older people are often not able to sleep for as long as younger people. That is why it is so important to protect yourself from amyloid plaque by always getting 8 hours of sleep.
I will stop now, but there is so much more happening during sleep, and so many studies proving it. Please ask if there is anything else you want to know!
**TL;DR:** Body and brain are restored, memories processed, consolidated, and sent to long-term memory, stress, anxiety, and trauma reduced, blood pressure reduced, muscle memory developed, brain growth/new ideas. Yes, 7-8 hours of sleep are necessary, even for the people who feel okay after less.
Quite new data shows that there are small drainages or “sewer system” in brain that activates when you sleep. It get’s rid of bad metabolites and proteins from neurons that accumulate to brain during their activity, for example tau-proteins that are believed to be the cause of Alzheimers disease. But that is most probably just part of the answer.
I myself took part to that study to find that out, two MRI:s and simultanious EEG, one after staying awake for 24h and sleeping in the MRI tube and other after normal work day. I myself am clinical neurophysiologist and work with EEG:s and brain activity during sleep every day. Fascinating stuff and a lot to be discovered.
Our bodies are made up of tiny workers called cells. Every little worker makes a bunch of trash as they work: scraps from building things, trash from packages, smoke from burning energy, and other junk.
Usually, the workers dump the trash into a river called the bloodstream. This works great… Except sometimes zombies come from the river and make the workers into more zombies. These zombies are bad cells like bacteria or viruses.
There are some important workers that control all the other workers. These boss workers are called brain cells. These bosses are so important, that they aren’t next to the river. It would be too dangerous to let the brain cell workers be attacked by zombies.
So, without the river, how do brain cell workers dump their trash? Basically, every day the workers stop working and instead spend their time carrying trash to a special fence. They can throw the trash over the fence into the river, but zombies can’t get through the fence. This cleaning time is called “sleep”.
While the boss cells are cleaning, the other workers cells aren’t doing as many things since they aren’t getting commands. They can do basic things like eat and do some general repairs, but they aren’t working together and as active as when the bosses are telling them what to do. This is why we don’t move as much when we are asleep… The boss cells aren’t giving as many commands, they are busy cleaning.
Tldr: The normal cells in you body work 24/7 and just chuck trash on the river. But the river is also dangerous and has zombies. Your brain cells are fenced off from the river to stay safe. Instead, they work a 16 hour shift, then close for 8 hours to clean and carry trash all the way to the fence to chuck it into the river. The clean up time is called sleep.
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