Eli5: Why do electrolytes hydrate you but saltwater dehydrates you?

Question

Eli5: Why do electrolytes hydrate you but saltwater dehydrates you?

In: 9

Answer 1

Because saltwater – assuming you mean ocean water – is 3.5% salt, which is way more than a saline solution at 0.9%, which is still more than an isotonic sports drink at maybe 0.5% salt.