Rapid Breathing, Rapid Heartbeat, Fever
The signs of severe dehydration warrant a prompt visit to hospital, or ambulatory services. These symptoms are mainly caused by a significant drop in blood pressure, due to the sheer lack of volume usually present as water.
Less oxygen and blood get to where they need to be, forcing the heart and lungs to work overtime. Fever sets in as your body works hard with nothing to cool it. Unconsciousness follows quickly without water; even if the person seems to be coming around after given water, it is best to make your way to a medical professional to be sure no damage was done.