I have read something similar before. I'm now 73, but drinking water was never a big thing all through the my childhood and adulthood, and no-one ever suffered from 'dehydration' back then. Sure, if you were thirsty, you'd have a drink of water (or squash, tea, etc.). This habit of needing to drink water all through the day is quite a recent thing, and I have had my doubts as to its necessity.
Nice to see it in print though!