Sciencemadness Discussion Board

Death by isotonic water

DoctorOfPhilosophy - 14-7-2016 at 15:59

The LD50 of water is about 90 ml/kg according to Wikipedia, death occurs due to an imbalance of electrolytes. How much isotonic water (electrolytes balanced) would you have to drink to die (or have a 50% chance of dying), and what would be the cause of death?

CharlieA - 14-7-2016 at 17:28

This is an interesting question. I have to admit that at first I thought it was frivolous, but a little further thought and the question intrigued me. Based on that LD50 and my body weight, I would have to drink 2 gallons of water to meet the LD50. Admittedly I drink 10+ cups of coffee a day, but I wouldn't be caught dead (pun intended) drinking that much water (I don't want to rust out my insides). :D
I was hoping to get a definitive answer to your question from my wife (RN, BSN), but you stumped her (she referred to the statement portion of your post as being called water intoxication).
I have no real training in biology/biochemistry, so my guess is just that. Even though one ingested isotonic water, I wonder if there are still trace elements that wouldn't be present in the water and thus maybe a needed concentration threshold of that trace element(s) would fall to unfavorable (fatal) levels. Or perhaps other substances in the blood would be diluted to harmful/fatal levels even if one ingested isotonic water.
So this is probably not a very helpful answer, but it did help me to pass the time while my wife was watching Big Brother! Thank goodness for my note book computer and headphones. I stay sane (assuming that I am sane) by checking SM and watching YouTube videos about chemistry and woodworking.
Thanks for the thought-provoking question.
Regards, Charlie

careysub - 14-7-2016 at 18:30

Quote: Originally posted by DoctorOfPhilosophy  
The LD50 of water is about 90 ml/kg according to Wikipedia, death occurs due to an imbalance of electrolytes. How much isotonic water (electrolytes balanced) would you have to drink to die (or have a 50% chance of dying), and what would be the cause of death?


"Isotonic water" simply has the correct osmolality, it may not have the correct proportions of all components of plasma, and it especially may alter the pH of the blood.

Special solutions that come very close are Ringer's solution that has sodium, potassium, calcium, chloride, and bicarbonate, or lactated Ringer's that had lactate instead of bicarbonate but has the same role of maintaining the proper pH. It would very difficult to die from infusion of Ringer's.

But I expect the cause of death would then be magnesium imbalance. Magnesium is involved in maintaining cardiac rhythm.

mayko - 14-7-2016 at 18:44

More on water intoxication:

https://www.erowid.org/chemicals/other/water_info1.shtml

macckone - 14-7-2016 at 19:12

Anyone who has preped for a colonoscopy will tell you 'a lot'.
Isotonic solution used for colon prep has potassium, sodium and magnesium.
PEG is also included to help prevent osmosis.
The prep is a one to two gallons and it is really hard to drink that much.
So the answer is probably that you can't drink enough of the nasty crap to kill you.
Long term it would probably lead to micronutrient issues but the lack of
food would likely be more detrimental.

NEMO-Chemistry - 15-7-2016 at 03:03

Quote: Originally posted by macckone  
Anyone who has preped for a colonoscopy will tell you 'a lot'.
Isotonic solution used for colon prep has potassium, sodium and magnesium.
PEG is also included to help prevent osmosis.
The prep is a one to two gallons and it is really hard to drink that much.
So the answer is probably that you can't drink enough of the nasty crap to kill you.
Long term it would probably lead to micronutrient issues but the lack of
food would likely be more detrimental.


My dad had a colonoscopy, he couldnt drink enough! Ended up on a drip for dehydration. They used stuff that is like body drain opener and boy it sure seems to work D.

Interesting question, some sports drinks are called isotonic i dont know if they actually are.

But i would think most drinks would have a MDS and that should have a LD50 on

macckone - 3-8-2016 at 22:14

Sounds like magnesium citrate or non-isotonic laxative.

PHILOU Zrealone - 4-8-2016 at 07:24

There is a sickness linked to Obsessive–compulsive disorder (OCD) called Potomania (Primary polydipsia) where people drink too much water.

At medium to long term it is lethal because it exhaust the kidneys and generates osmotic disorders into the body (some biochemical pathways or medias (blood) are too diluted).

Tsjerk - 4-8-2016 at 07:43

Potomania is linked to drinking non-isotonic liquids. Isotonic liquids are as far as I know not never linked to death.

AJKOER - 4-8-2016 at 10:43

Do recall a reported case of a child dying from drinking too much water.

So the risk, although rare, is apparently real.

feacetech - 4-8-2016 at 16:15

eventually death would occur by the same way would it not, i.e. swelling of the brain, it would juts take longer as there would be no osmotic action encouraging swelling of cells depending on how fast your kidney can send the excess to your bladder

macckone - 5-8-2016 at 06:32

Water can definitely kill you. Non isotonic saline can kill you. The question is, can an isotonic solution kill you, and if so hou much?

Tsjerk - 6-8-2016 at 06:35

I don't think complete isotonic liquids can kill you, except that you will after some time die form the lack of (micro)nutrients if you drink to much. As mentioned earlier in this tread.

Of course plants and humans are not completely comparable, but plants can be grown(!) on isotonic liquid while they are completely submerged in the liquid as long are there is enough aeration.

Just put the right salts together with some sugar, protein, fat and vitamines and I think you can live on it and discharge any excess without it killing you. At some point the concentrations of stuff in the liquid will be same as that inside your body and you should then be fine with any amount.

Cholera can make you produce isotonic liquid (via a certain body opening), the treatment is one liter per hour of isotonic liquid intravenously. Effectively you are bleeding one liter per hour from below without loosing blood cells.