“The brain sends messages along neural pathways through both chemical and electrical ways of signaling. Those pathways literally need to be lubricated enough by hydration so that they can do that. Even for an electrical charge to pass, there has to be something that can conduct that charge. For chemicals, we need building blocks like Vitamin D to build enough serotonin, but we also need water. The whole body, but particularly the brain, is largely made up of water, so it's just a case of providing the basics.
A really good way to judge hydration is your hair and skin. Because they’re extremities of your body, it's really obvious if you're dehydrated. But by the time you can sense an obvious sign of dehydration — and that's usually at 1 to 3% — you already don't have enough water in your brain to conduct those messages efficiently.
A few years ago, there was a journalist in the UK who started to drink the right amount of water for them for a month, and the changes that they reported in their sleep, mood, and decision making power was really incredible. I was pleased because that's the kind of thing I talk about all the time, but it was interesting to isolate that one simple thing.”
