How Long Can You Live Without Water? Dehydration Hits Faster Than You Think

If you lost internet access, cell phone service, and electricity right now, you’d probably feel like your days on the earth were numbered. At the very least, you’d probably get really bored, really fast.

But you’d suffer a lot more without the most important thing you likely take for granted every day.

Water is more accessible to the masses overall than it has ever been before. In many places around the world, all you have to do is turn on a faucet and you’re good.

How important is it for daily survival, exactly? Judging by the amount of time you could technically live without it: extremely.

What happens if you stop drinking water?

Woman drinking from water bottle.

Woman drinking from water bottle. | M-imagephotography/iStock/Getty Images

When it comes to survival, water is your most important resource. Without food, you could survive multiple weeks doing just fine — even longer on a surprisingly low number of daily calories. But without water, you would soon find yourself counting down the hours.

Water keeps your body functioning normally, since it makes up the majority of what lies beneath your skin. Without it, you could develop heat stroke, kidney problems or worse. Go too long without drinking anything, and you’d probably start having seizures and lose so much blood volume your body would run out of oxygen.

How long does it take for dehydration to start causing severe — even deadly — health problems? It could happen a lot sooner than you think.

How long could you live?

You could technically survive for up to three or four days without water. But it would depend on other circumstances, such as whether or not you were still eating, what those foods were, and the temperature at which you were trying to survive.

Because at least 60% of the human body is made of water, the more you lose, the faster you’re going to die. If you’re enduring extreme temperatures, you’d lose water alarmingly fast through your sweat. Chances are, you wouldn’t even make it to day three.

Eating foods with a high water content and enduring cooler weather might extend the amount of time you could survive without drinking water. But not by much.

How to tell if you’re dehydrated

Water glass

Water glass | Pinkomele/iStock/Getty Images

The human body isn’t as easily dehydrated as it might seem, especially if you spend a lot of time in air conditioning with an easily accessible food and water supply. But if you didn’t have something to drink for even just a day, you’d start to feel it.

Dehydration isn’t just about feeling thirsty. You might feel fatigued, confused, or dizzy. You might develop a dry mouth and tongue. You’ll sweat less than usual or stop sweating altogether. And you’ll definitely pee less often than you typically do. If your urine turns a dark color, you’re in trouble.

There are also a few less common signs you aren’t drinking enough water — including dry or oily skin and a rapid heartbeat.

The bottom line: if you take nothing else with you when you work out, go on a hike, or otherwise venture far from civilization, always bring water. Humans can survive for a long time without most things, but this is definitely not one of them.

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