How long can you live without water?
Most people can survive only about three days without water, though it can be shorter in heat or longer in cool conditions. The body loses water constantly through breathing, sweat and urine.
Water is needed for blood flow, temperature control and removing waste. As the body loses water, blood thickens, blood pressure falls and the kidneys can fail. Severe dehydration causes confusion, rapid heartbeat and eventually loss of consciousness.
How long someone can survive depends on temperature, activity, age and health. In hot weather with physical effort, a person can lose more than a liter of sweat an hour, and dangerous dehydration can happen within a day.
The rule of threes
Survival experts often use a rough rule of threes: a person can survive about three minutes without air, three days without water and three weeks without food. These are only rough guides, not exact limits.
Did You Know?
Signs of dehydration include thirst, dark urine, dry mouth, headache and tiredness. Babies, older adults and people with illnesses are at higher risk.
This answer is general information, not medical advice. For a personal health question, talk to a doctor.