If energy can’t be created, then why does sleep boost us back to 100% every morning? If I don’t plug in a laptop and I put it in sleep mode, it just drains battery less quickly. If it’s from food, why does our body wait until sleep to convert it to energy?
AirborneRodent: It’s from food, and the body doesn’t wait until sleep to restore energy. This is why a workout or athletic activity feels so much easier a few hours after a meal rather than on a starving stomach.
What sleep restores is not your energy, but your brain function. Your brain is floating in a nutrient soup called *cerebrospinal fluid* or CSF. Throughout the day, your brain cells drink in nutrients from the CSF, and spit out waste. This builds up, and by the end of the day there’s so much waste floating around in the CSF that it starts negatively affecting brain function.
When you sleep, channels open up and flush the day’s supply of CSF away. New, clean CSF is pumped in for tomorrow, and so you wake up with a clean brain.
Leiva-san: Your brain continuously creates something called adenosine while you are awake. This keeps you energized and ready to do anything. The more adenosine your brain makes, the more it has to carry, and sleeping is the only way to get rid of it. The more it carries, the more it gets tired.
Your brain also has an alarm clock called a ‘circadian rhythm’ of when to do certain things at certain points in the day.
Let’s say it’s night time, your brain is carrying way too much adenosine, luckily the ‘circadian rhythm’ tells the brain it’s time to sleep. Because it’s sleepy time, your brain creates something called melatonin. This makes you comfy, mix that with being tired from all of the adenosine and you get sleep.
During sleep, your brain starts putting away your memories it was holding throughout the day away into a library known as your long term memory (REM Sleep). This is when you dream, usually it’s associated with whatever your brain is putting away.
Your brain is also firing old bad cellular workers and hiring new good ones that are ready to work.
Meanwhile, your body’s cellular workers destroy the adenosine while making important fixes and adjustments to the body. When the circadian rhythm says it’s time to wake up, your brain stops making melatonin. You have no adenosine so you feel tired, but this is also an incentive to wake up since your brain is satisfied that the adenosine and melatonin is gone. Your cellular workers fixed any problems they saw so your body also feels good.
You do gain your energy from foods mostly as types of sugars that are fed to the little cellular workers in your body. Because your body is always working, you will always be converting food or fat into sugars to feed your cells.
sharpystirling27: No one knows, we only have theories at this point in time. Theoretically theres no evidence we need sleep. But we know thats not true.