Exactly what happens to a person when they drink sea water? I know that it can be fatal, but what amount does it take to kill someone?
The Master speaks: What would happen to you if you drank seawater?
TL;DR version: You get too much salt which can seriously mess up your metabolism (in short you dehydrate). In the meantime your kidneys overload with salt trying to get rid of it and shut down. This is a Bad thing[sup]tm[/sup].
Here’s the article on the topic from the Straight Dope Column.
Short answer: you dehydrate. Remember “osmosis” from high school chemistry? If you have a membrane with a low amount of solutes on one side and a high amount on the other, water will move from the area of low concentration to an area of high concentration.
In this case, seawater is higher in concentration for a bunch of solutes (including, but not limited to sodium, potassium and magnesium) than your cells are. The cells will lose water to your digestive tract and blood as the water leaves the cells’ low concentration for the high concentration. As your brain cells lose water, you get seizures and coma. When cells in your heart lose too much water, your heart has trouble beating correctly (and having excess sodium and potassium from the sea water also mess up the heart’s rhythm). You’ll have a some pretty hellacious diarrhea from the excess water pulled into your digestive tract. Your kidneys start to work harder and faster to filter out all the solutes in the seawater and eventually they can’t keep up and they fail.
Okay, thanks for the info! I appreciate it.
I thought I read somewhere that seawater isn’t as bad for you as we thought. Something about some shipwreck survivors who survived due to drinking seawater instead of just dehydrating and dying.
Did I dream this? I presume if you are going to die of dehydration anyway, drinking seawater couldn’t possibly be worse. I guess the trick is knowing where the line is.
No, it just won’t work. You’ve had the condensed version of Uncle Cecil’s missive, now here’s the ultra-condensed: You can’t make pee saltier than sea water. If you drink any sea water, you will need some fresh water to make urine, or you body will suffer. What I had heard was if you’re not dehydrated, and you have some fresh water, you can mix it with salt water, maybe 3 to 4 volumes fresh : 1 salt, to stretch your supplies, presumably existing water reserves in your body will compensate.
A seriously dehydrated person drinking salt water is supposedly a tragic circumstance. I’m sorry I don’t have a YouTube link, but the story goes, the salt water will only briefly moisten the throat membranes, the saline solution will actually pull more moisture out. They drink and drink and become more and more crazed as it just doesn’t work, maybe even drowning before the the excess salt has a chance to cause death.
On further investigation, I may have been thinking of Alain Bombard who crossed the Atlantic in 1952 on a raft and claimed he ate only fresh fish and drank seawater. He’s dead so we can’t ask him, but it looks like some people don’t believe his claims.
If he kept his metabolism down, he may have been able to survive on just the fish, presuming that he didn’t mind swallowing them raw and not wasting any fishjuice.
That inspired Lindemannto cross the Oceans in a Klepper foldable boat to figure out how shipwrecked seamen could survive better (he was a doctor of medicine). He drank rainwater and used the fish juice.
I was surprised when reading Thor Heyerdahls Kon-Tiki story - where they also drank rainwater - that at first, they had a problem with sweating a lot and therefore drinking too much sweet water, until they hit accidentally (from spray) on the perfect solution: salting their morning porridge with salty sea water kept the balance to the salt lost later to sweat, and thus they were no longer continously thirsty.
Maybe that was meant: adding a tiny bit of sea water to fresh water to keep the sodium balance.