What would actually happen to your body if you stopped drinking water, including all beverages that contain water, like juices, soft drinks, and tea? Let's just say it wouldn't be pretty - your body is made up of 60 percent water, which is reason enough to make sure you're constantly replenishing your supply. All that water works really hard to ensure that you continue functioning properly, by transporting vital nutrients and hormones to where they need to go, cushioning our joints, regulating our internal temperature, and lubricating our eyeballs.
But we lose a whole lot of it through processes such as urination - about 1.5 litres a day - defecation, and sweating, so we need to know when we should be upping our intake. That's where the 'thirst centre' of the brain, which is located in the hypothalamus, comes in. It's constantly communicating with the blood vessels to figure out how hydrated you are, and when your hydration levels drop below ideal, your brain will tell you that you need to drink something now.
So what happens when you don't? Well, as the AsapSCIENCE video explains above, it'd take a little while, but eventually your brain would start to shrink in size, and you'd feel light-headed and have a higher tolerance for pain. Studies have also shown that a thirsty brain is a less efficient one, with dehydrated participants' brains requiring more oxygen to perform a task than hydrated ones.
Then comes the lack of peeing and swallowing, the nausea, and the delirium. Nobody ever said it would be pretty. Watch the episode of AsapSCIENCE above to run through all the gory details of Death by Dehydration.