Can someone survive without water?

How long can you survive without water? Biologist gives the answer

REUTERS / Francois Lenoir

We cannot feed on air and light alone. The human body needs water and solid food to survive.

A person can endure up to three weeks without food - Mahatma Gandhi fasted strictly for 21 days - but different rules apply to water.

It is made up of at least 60 percent of an adult body, and every living cell needs it to function. Water is the lubricant for our joints, regulates our body temperature through sweating and breathing, and helps flush waste from our bodies.

The maximum time anyone can go without water is one week; an estimate made from observations on the dying. This is what George Washington University professor of biology Randall K. Packer told Maggie Fox of NBC News in 2013.

But a week is well meant. Three to four days is the more likely option, especially when exposed to extreme situations such as heat.

"About 100 hours without drinking is possible at moderate temperatures," says Claude Piantadosi from Duke University to Fox. “When it's colder, even a little longer. If you are exposed to direct sunlight, a little less. "

The danger of dehydration

Our bodies are constantly losing water - even when we breathe out - which is why drinking one glass a day is not enough.

“Under extreme conditions, an adult can sweat 1 to 1.5 liters of water per hour,” writes Packer in his article for “Scientific American” 2002. “If the loss is not replaced, the water supply can drop rapidly - in the worst case it is reduced even the amount of blood. "

When that happens, blood pressure also drops to levels that can have dire consequences.

If we stop sweating, our body temperature also rises to an alarming level.

Dehydration that "causes more than 10 percent loss of our body weight is a medical emergency," according to the University of Rochester Medical Center, "and can be fatal if not avoided."

For water absorption

We also get some water through solid food, "but drinking water is the main and best form of water intake," says the US National Institutes of Health website.

Other beverages, such as juice or milk, can also keep the body hydrated. The only thing better not to drink is alcohol. It has the opposite effect.

Translated by Lena Anzenhofer