What happens to our bodies if we don't have any water?

Drinking water, ingesting water either through actual drinking or intake through water-infused foods, is necessary for a number of metabolic reasons. Many systems in your body rely on proper hydration levels. The general term for too low hydration is dehydration. The symptoms of dehydration are as follows:

Initial onset: (at or before the 2% loss of bodily water volume)

• flushing of the skin
• headache
• increased thirst and dry mouth
• decreased urination
• loss of appetite
• dry skin (especially chapped lips)

Mild dehydration: 3-5% loss of volume

• increased thirst
• decreased urine volume and concentration of urine
• tiredness
• decreased or lack of tears
• dizziness

Moderate dehydration: 4-6% loss of volume

• increased thirst
• no urine output
• decreased sweating (sweating may cease)
• lethargy
• confusion
• seizures
• decreased blood pressure (hypotension)
• fainting
• sunken eyes
• and in infants sunken fontanel (soft spot on the top of the head)

Severe dehydration: 6-10% loss of volume

• heart rate increase
• respiration rate increase
• increased body temperature
• headache
• nausea
• tingling in extremities (parathesia)
• twitching muscles
• dim or unfocused vision
• urination, if possible, may be very painful
• delirium (marked by manic state, hallucinations, delusions incoherence)

Fatal dehydration: 10-15% loss may be recoverable, but greater than 15% is usually fatal.

• shrivelled or wrinkled skin
• unconsiousness
• Death

That persons urine will then also turn yellow, as this is because the persons' body is not digesting food, and liquids.