Patrick Dempsey · August 27, 2026 · 4 min read
There is a piece of hydration advice so old and so sensible that nobody thinks to question it. Drink when you're thirsty. It's in every training manual. I've repeated it plenty of times myself. And somewhere in our fifties, quietly, it stops describing us.
Wherever you are in the season — banking this for next summer if you're up north, walking straight into it if you're reading from Australia, New Zealand or South Africa — this is the part worth knowing before the first hot day rather than during it.
Below: the study that made me stop repeating the old rule, why "toughing it out" is the wrong frame for any of this, and what to do in the meantime. Next Thursday the video goes up, and the letter that comes with it carries the actual protocol.