but if you’re already dehydrated it can make the situation worse.
No, it won’t. That’s the point of the misconception. You even get to it later then dismiss. We aren’t taking about overall health. We aren’t talking about the 'betes.
None of those things will dehydrate you more despite people saying differently. Not soda, not milk, even beer under 2% beer will be better. You will be rehydrated, there WILL be a net gain of water in your body. There is no net loss of water no matter how much people say sugar or caffeine will lower the net gain.
If you’re dehydrated, you’re lacking salt. There’s a reason why physically demanding companies provide free drink packets to their crews. They don’t want road crews dying by the side of the road because they slammed water and had no salt on a 100 degree day working next to a machine shooting out molten tar and rock. We aren’t pumping people’s blood full of sterile water. Saline bags are .9% salt for a reason.