The more I age the more important hydration turns out to be. Gastric issues, joint pain, blood pressure, weight problems, kidney stones, bad breath, constipation.. and now brain issues too? Do yourself a favor, and start drinking a ton of water!
Not too sure - an overload of water can actually be dangerous i think.
You need more hydration in hot climates than in cold damp ones. Also your activity influences how much hydration you need.
Ps I don’t think the article is about how much water you drink. (Edited to make the last sentence clearer)