Most of us are aware that drinking water is essential for life and is the most important requirement of survival. Water is critical to many metabolic processes (important chemical reactions inside the body) and dissolves many substances for use in the body. Approximately 70% of the human body is made up of water. Humans lose water through sweat, urine, feces and breathing, which means that it must be replaced each day. It is estimated that each person in the United States consumes about 2 liters (0.5 gallons) per day from beverages and food. The amount of water required depends on the individual, exercise and climate. For example, dehydration (excessive loss of fluid) can set in after just 1 hour of exercising in a hot and humid environment. If you have ever wondered how long a person can survive without water, read on to find out.
How long can a human survive without water?
The average person can only survive for 3-5 days without water. However, this time can be shortened by high temperature, high humidity levels, exercise and/or poor health. It can also be extended in lower temperatures, lack of exercise and good health. Some people have been known to survive for more than 10 days without water, but this is highly uncommon.
This should never be tested and can cause severe symptoms of dehydration that can be fatal. Some of the early signs of dehydration are lack of saliva as well as decrease in frequency and amount of urine (it may also have a deeper color and strong smell). More severe dehydration can cause rapid heartbeat, vomiting and diarrhea, and eventually shock.
Did you know?
A number of sources recommend 8 glasses of water per day, but this number is debated by many professionals. It is recommended that adult males consume 3.7 liters (1 gallon) per day and females 2.7 liters (0.7 gallons) per day from all sources.
It is also dangerous to consume too much water. This is called water intoxication (water poisoning) and can also be fatal.