But why is that? Do they want to lose weight? No, they don't, of course ;P

I guess you have heard of the lymphatic system. It's one of the most important parts of our body's immune system. It transports white blood cells for example and it runs across your whole body. 

Except across the brain. The brain is a bit special, you know. It is very important and thus needs to receive special protection. It is surrounded by the blood-brain barrier that separates the "body" from the brain and determines which molecules from the blood stream may enter the brain. This is a protective measure, because we don't want everything in our blood ending up in the brain. When there's a bacterium or a virus floating around, we certainly do not want it to deposit itself in our thinking apparatus.

The blood-brain barrier also works the other way around. Not everything from the brain is let out into the blood. Waste products build up during normal cellular processes and accumulate in the brain during the day and they can't just "leave". But we need to somehow get rid of these waste products, right? They can't just stay in the brain until we die, our brain couldn't function properly anymore.

So the brain has set up something similar to the lymphatic system, just more like a special edition thereof. It has almost the same name, but you have probably never heard of it so far. It's called the glymphatic system. And its function is to detox the brain. The brain has its very own detox system, isn't that cool? It is fluid and it transports molecules, like the blood and the lymphatic system do.

How sleep plays into the whole cake

The glymphatic system has working hours as well. The magic happens when you sleep! This is the time when the glymphatic system is most active. 

Now the crucial point: The brain cells, also called neurons, intentionally shrink to create space for the glymphatic fluid to flow through the brain to clear out the waste that has built up! This is like when you have to vacuum clean your room and you remove the chairs to get rid of the dirt underneath because otherwise you cannot access it and it stays dirty. But as soon as you have cleaned underneath, you put the chairs back, right? 

 The neurons do the same. When you wake up, they expand again to their original size and the glymphatic system cuts back its activity.

When you have slept well, your brain feels fit as fuck and you feel fit as fuck and you're not as forgetful and you can think clearer. That's due to the work of the glymphatic system, among other things. The longer the sleep and better the sleep quality, the more effectively the glymphatic system can do its job.

When you don't clean underneath the chairs, you can see dirt building up. Now imagine not properly cleaning for two months, a year, 10 years.... I guess you can very well imagine what happens in the long term.

The same is true for our brain, when you don't get your sleep right. The detox mechanism cannot execute its function properly! The waste products are not being removed from the brain, instead they accumulate. 

The risk for getting dementia and Alzheimer's increases, or just generally spoken, you degrade cognitively. I know, you're not 60 years old yet and worrying about such things, but you know what I mean. 

Start caring for your brain early in life, as you cannot just "fix the damage" when you're older. Make sure you're getting your beauty sleep, as a health diva certainly would ;P