When your body loses too much water and salt, it can't function properly. And that's called dehydration.
Water can be lost through diarrhea or vomiting. Active adults can also lose water through exercise and sweating. And even those who aren’t active can become dehydrated if they don’t drink enough water.
Mild dehydration can be reversed with rehydration therapy. However, left untreated, mild dehydration will worsen. Treating severe dehydration requires intravenous fluids and a hospital stay.
