General Question

Steve_A's avatar

If you were completely dehydrated, how long does it take to re-hydrate?

Asked by Steve_A (5125points) June 27th, 2010

Lets say you take an average person, they become almost or completely dehydrated, close to being deadly you might say or making them very fatigued and need rest.

How much water do they need to drink?

How long does it take for the water to re hydrate them?

Observing members: 0 Composing members: 0

25 Answers

CaptainHarley's avatar

“Completely dehydrated” = dead

If you mean “almost dead,” then probably about four to five hours to rehydrate.

Axel's avatar

When your wee is watery again, then you are there!

Seems to take hours after remembering to start drinking water.

The trouble is, if you forget to drink, by the time you feel de-hydrated, you are now hours away from completing a re-hydration process.

Salts etc are also an issue.

CaptainHarley's avatar

@Axel Indeed! Your electrolytes would be completely screwed!

LuckyGuy's avatar

Typcial ER treatment for dehydration is 1 liter IV push, about 20 minutes. 1liter follow up delvered in about 1 hour. You will have the urge to pee one hour after the IV finishes.

Note: Your mileage may vary.

CaptainHarley's avatar


We use to titrate for cases of severe dehydration in Vietnam.

Steve_A's avatar

@Axel So if you go past a certain point you have to wait for hours regardless of how much water you start drinking?

and by watery you mean clear right?

Steve_A's avatar

@CaptainHarley What is a titrate?

CaptainHarley's avatar

It might be what you call “push.” We would tape two bags of normal saline together, insert the biggest needle we could find, and squeeze the bags with both hands.

Steve_A's avatar

@CaptainHarley Dam sounds like it would hurt…...

Steve_A's avatar

@All Also I found this, would you say it is right or accurate?

CaptainHarley's avatar


That’s an AWFUL lot of water for me, even in a hot climate!

Steve_A's avatar

@CaptainHarley How much did your test say?

Mine was around 2.1 liters it said I would need on a regular day…..

ipso's avatar

Extreme heat/dehydration (i.e. dizzy and approaching the point of passing out) can affect your optimal athletic performance for a couple days – even if you’ve had “optimal” recovery (drink/food/electrolytes/rest/temperature/etc.)

So mean re-hydration only takes a few hours, but total recovery takes much longer.

I guess that is obvious though.

LuckyGuy's avatar

@CaptainHarley On this side of the pond we have the luxury of more time to “push”.
Also there are fewer bullets flying around.

Lightlyseared's avatar

@Steve_A to titrate means to give the fluid (or medication) in measured dose bserving for the effects before deciding to if you should give more or not. It’s important when giving moephine for pain, for example, where you want to give enough that the patient is not in pain but not too much that they stop breathing.

Steve_A's avatar

Also this is a little off-topic but it says

“Don’t drink all of the water you need per day all at once. Divide the amount you need and drink several glasses of water throughout the day. This is especially important if you engage in lots of heavy exercise.”

Why is that and what happens to the body if you drink all the water at once?

quasion's avatar

If you loose 30% of your vascular volume you will get into shock. (maybe that’s what you mean for nearly death) The time to fully rehydrate depends of the means you use to replenish your body water. In the ER, IV saline is used to get the patient out of shock (about 50 ml per kilogram in one hour). Afterwards you have to compensate for previous looses and the current liquid needs to fully restore the normal hydratation, this could take 24 hours. If you use the oral way it could take longer. It also depends of the kind of solution you have. Very diluted liquids should not be given fast for the risk of water intoxication and neurological impairment.

Lightlyseared's avatar

@Steve_A if you drink all your days supply of water at once most of it will end up as urine. If you engage in heavy exercise you will lose water as sweat so even though you have drunk enough water you will end up dehydrated as your body has got rid of most of the water you drank before the exercise.

CaptainHarley's avatar


LOL! Yes, it definitely makes a difference when you’re trying to administer medical aid when the air is full of lead! : D

CaptainHarley's avatar


That site says 120.5 oz, or 3.6 liters

“A person who is 235 pounds
and is exercising for 30 minutes ,
is not pregnant,
is not breastfeeding,
does not live at a high altitude,
does not live in a dry climate,
drinks 0 alcoholic drink(s),
when the weather is not very hot or very cold,
and is not sick with fever or diarrhea should have:

120.5 ounces of water today, or 3.6 liters.”

Flavio's avatar

If you are still peeing, just drink 8 glasses of water and then eat a healthy meal. If your kidneys stopped producing urine go to the hospital.

PandoraBoxx's avatar

120 ounces = 3.75 quarts, or almost a gallon. The site said that 20% of your water intake comes from the food you eat, so drinking 3 quarts is what’s recommended.

The 3 pm fatigue that people feel is often as much from needing hydration as it is from your blood sugar levels dropping after lunch. Spreading water out throughout the day is a good idea.

Neizvestnaya's avatar

For a person not near enough death to require a trip to the emergency room then a soak in a tub full of tepid water while drinking a hydration/sport drink every hour for a few should right them. A nap will help too.

JLeslie's avatar

@Steve_A You can flood your tissues and die if you guzzle way too much water at once. Your kidneys can not flush fast enough, and your electolytes get whacked.

Here are two articles you might be interested in some of the notable cases at the bottom of the page.

Answer this question




to answer.

This question is in the General Section. Responses must be helpful and on-topic.

Your answer will be saved while you login or join.

Have a question? Ask Fluther!

What do you know more about?
Knowledge Networking @ Fluther