this post was submitted on 04 Jul 2023
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I mean, I've heard that you can typically only survive about three days without water, but what exactly causes your body to fail when you dehydrate too much?

I guess one point is lack of salts (if you sweat a lot) but I'm specifically wondering about lack of water (although a closer explanation about how lack of salts will kill you is also appreciated)

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[–] [email protected] -4 points 1 year ago (2 children)

It is a common misconception that you need salt when you exercise and sweat a lot. You absolutely do not need salt.

[–] [email protected] 5 points 1 year ago (1 children)

That's a very incorrect statement. NaCl, KCl, and MgCl2 are essential for our bodies to function appropriately. If you are working out for an hour or mowing the lawn on a hot day, you are mostly correct. You can replace the lost salt though a balanced diet. If you have sustained sweating, such as when you run a marathon or play a match of football, it can be deadly to not replace these salts.

[–] [email protected] -3 points 1 year ago (1 children)

In the vast majority of cases, people don't need salt when they exercise. You just described a fringe case that virtually no one experiences. You high school football coach shouldn't be giving you salt. That could be dangerous. They should be giving you water.

[–] [email protected] 6 points 1 year ago* (last edited 1 year ago)

The coach won't be giving them salt directly, but will always provide a sports drink which contains salts.

Ever watch any sport and a player falls over with a cramp? They have drunk too much water and not enough electrolytes.

Here's a study from one hospital in Oslo, Norway. Norway is not considered a hot region of the world. Between 2010 and 2015 they treated 31,000 patients in the ER from a population of 135,000 for electrolyte imbalance. That's roughly 18 patients a day. This is not some sort of fringe case.

[–] [email protected] 3 points 1 year ago (1 children)

Salts are absolutely necessary for ordinary nerve- and muscular function. If you've ever sweated a lot without eating or drinking some salt solution you would notice your muscles start twitching, vibrating and cramping. After a while you can also notice getting light headed and blurry vision.

Source: Been in situations with plenty of water but no salt, and enormous amounts of sweat. Been in the same situations with access to salt for comparison.

[–] [email protected] 1 points 1 year ago* (last edited 1 year ago)