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Nullo's avatar

Can a person stay hydrated without drinking anything?

Asked by Nullo (21968points) August 5th, 2013

In his book, Kon Tiki, Thor Heyerdahl observed that the guy whose job it was to steer the eponymous raft across the Pacific Ocean would, despite being in the hot sun for some hours at a time, not need a water break. He proposes that this might be because the skipper was almost continuously being hit with waves.
It seems to make some sense, but over the years we’ve learned that many of his observations turned out to be only partly correct.
I nearly died of dehydration over Christmas due to a killer sore throat, was thinking that if soaking yourself works, long baths might be less expensive, more practical than going to the ER for an IV.

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16 Answers

seekingwolf's avatar

If it were fresh water waves, sure…as long as he was ingesting some water from it in his mouth.

But not salt water. Salt water dehydrates you. We can’t drink it.

We can’t absorb water through our skin in the quantities needed to prevent dehydration.

BhacSsylan's avatar

Yeah, you need to drink. Even if this story is true, he would be drinking something by swallowing water from the waves (assuming it was fresh water as @seekingwolf mentioned). It takes a highly specialized organism to be able to live off of water from other sources than simply drinking.

Of course, it also depends on what you mean by ‘without drinking anything’. Are we talking days? Or just the ‘some hours’ you mention (and how many hours?)? Because that is more plausible, and probably it was just a few hours and he was used to it, and drank a ton of water when off duty.

flutherother's avatar

I remember reading somewhere that a salt water enema would keep you hydrated. I’m not sure if this is true.

rojo's avatar

You could do it via IV but you are still taking in fluids, just through a different method.

ragingloli's avatar

Maybe you should write an e-mail to bear grylls.

JLeslie's avatar

For a few hours I am pretty sure I would live. The water hitting him means he doesn’t need to sweat. I spend time at the pool sometimes for a couple hours. I do get thursday, but I’m not dropping dead so fast. It would be different for different individuals. How much they may have eaten, if their diet has enough salt that they hold onto fluids, etc.

augustlan's avatar

I would assume that you could manage it if you ate a lot of food that had a high liquid content. I don’t see how salt-water waves would be helpful, though.

JLeslie's avatar

Why does it matter if it is salt water or fresh water if he is not ingesting the water?

Jeruba's avatar

Now you’re making me curious about whether it’s possible for us to take in enough water from high-water-content fruits and vegetables (for example, cucumbers, lettuce, apples, oranges) without actually drinking. I know that some animals are said to get enough water from the plants they eat to survive in arid climates.

seekingwolf's avatar


Sounds like its time for an experiment. Take something like lettuce, a large piece, weigh it ans then dehydrate it. Then weigh it again. The difference in weight can be used to calculate the amount of water in one large piece of lettuce.

Lets assume ans say that the average human needs about 60 oz of water a day. How many lettuce leaves would that take?

ETpro's avatar

Yes, you can stay hydrated just fine with retention enemas, but NOT with salt water. Whether you drink water, inject it in the other end, or soak a bit in through the skin, the basic rules of osmosis determine which way the water flows. If the water outside the membrane (be it stomach lining, intestinal walls or skin) is less salty than your internal bodily fluids, water flows through the membrane into the body. It it is saltier, water flows out to try to dilute the saline solution. That’s dehydrating.

If you ever have a medical need to stay hydrated and can’t swallow, have someone visit a medical supply, or go online and order for overnight delivery a double balloon retention enema nozzle. That will let you easily retain water for long enough for your body to completely absorb it. And you can rest comfortably in bed secure in the knowledge you won’t have any embarrassing leakage.

And DO NOT ask me how I know this. :-)

JLeslie's avatar

@Jeruba I think you could last a long time on watermellon. But, I dn’t think the man in the story fr this Q has time to eat. He doesn’t have time to drink.

@ETpro Ok, so if we do indeed absorb the salt through our skin, still, it’s just splashing on him and it isn’t the dead sea. Are you saying I am dead in a few hours if I wind up treading water in the Atlantic because my boat sank?

ETpro's avatar

The salt on the skin would draw water out through it. Water would not go through the membrane into the less salty blood and lymph. You’d last in the Atlantic for a good long time if your head was above water, the ocean temperature was sufficiently warm and no large predators happened by to make a meal of you. This is because our skin is a very poor osmotic membrane, not nearly as permeable as the stomach lining, and nowhere close to as permeable as the lining of our small and large intestines. Even when you drink water to hydrate, most of it is actually absorbed after it leaves the stomach.

JLeslie's avatar

@ETpro Alright then. So, don’t you see the guy in Q probably surviving? He is just getting splashed. If the water is a little cool even better possibly in this case, he is in the blazing sun remember. Although, the Pacific is more than a little cool. It’s cold.

ETpro's avatar

If the water is fresh, as in a giant lake, then he could lap up enough to stay hydrated. In the ocean, no, he wouldn’t last very long. Bear in mind that Daniel Chong survived almost 5 days without any water in a DEA holding cell.

JLeslie's avatar

@ETpro That story is horrible. What’s not too long? Again, I easily have spent two hours at the beach on the Atlantic coast in and out of the water without eating or drinking. I wasn’t desperate from dehydration.

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