What Your Brain Actually Does While You Sleep

You spend about a third of your life asleep — roughly 25 years if you live to 75. From the outside it looks useless. But sleep isn't your brain switching off. In some ways, it's when your brain works hardest. In this video: • The teenager who stayed awake for 11 straight days • How your brain washes out its own waste at night (the glymphatic system) • Why rats "replay" their day while they sleep — and so do you • What caffeine really does to your brain (it doesn't give you energy) • Why being awake 17–19 hours is like being legally drunk • What happens to heart attacks when we lose ONE hour of sleep • The dream that may have helped create the periodic table Chapters: 0:00 The most "useless" thing we do 0:48 264 hours without sleep 1:22 What is sleep actually doing? 1:43 Your brain's night-time cleaning crew 2:27 Replaying the day: how sleep builds memories 3:08 Adenosine and your morning coffee 3:46 Tired vs. drunk 4:17 The daylight saving experiment 4:46 Solving problems in your sleep 5:22 Putting it all together Tonight, when you switch off the light, you're not stopping. You're starting the night shift. #sleep #brain #science #psychology #health