You're right.

A simple, easy medical test for dehydration is to take a pinch of skin from the back of the hand or wrist between your thumb and forefinger and lift it up from the surface. If the skin remains tented up above surrounding skin level instead of immediately returning to level, then the patient is dehydrated.

The real secret to managing dehydration is prevention. Drinking water upon waking and again before starting the day's heat exposure activities, and being encouraged to drink at regular intervals throughout the day, will help. Gatorade or other sports drinks often popular, but are really no better than water. Given a normal diet, neither sports drinks nor salt tablets are usually necessary. However, some people do eventually get tired of having to drink plain water, so some sort of flavoring can help them to maintain adequate fluid intake.

Also, one of the simplest and most effective interventions for mild hyperthermia or uncomplicated heat stress is to have the patient immerse their hands and forearms into a bucket of tepid water. This technique has been clinically validated, and is quick and convenient, since all you need is water and a bucket, no icepacks, no towels, no fans, etc. It's also easier to get some people, especially the Type-A's, to do that than to get them to lie down with ice packs or cold damp towels applied to their groin, armpits and neck, or accept other interventions.