Salty water and hydration

[tim.tdj]

Hi Everyone

There is something which confuses me.

I have read that if you add salt to water, it helps with hydration.

I have also read that adding salt to water makes you pee more. Wouldn't this cause dehydration?

How can both of these statements be true? I would be very grateful to anyone who can remove my confusion about the relationship between salt and hydration.

Thank you very much.

Kind regards

Tim

[Phi for All]

The body MUST maintain a tight ratio of salt to water, so if you increase salt intake, your kidneys retain more water to compensate. It's possible the article you read counted this retention as helping with hydration.

I don't know about salt making you pee more. Can you link to the article you read? Popular science writers are notorious for trying to punch up dry subjects with excessive "moisture". 

[tim.tdj]

39 minutes ago, Phi for All said:

I don't know about salt making you pee more. Can you link to the article you read? Popular science writers are notorious for trying to punch up dry subjects with excessive "moisture". 

Hi Phi

Thank you very much for your reply.

Unfortunately, I can't find the original article I read but I have just found another one which says something similar. It basically states that as a result of osmosis, extra salt in your blood sucks water out of your cells. The other article went on to say that you pee out the water that has been sucked out of your cells. You can see the article I have just found here:

https://sciencing.com/drinking-salt-water-dehydrate-you-6454208.html

[Phi for All]

1 hour ago, tim.tdj said:

It basically states that as a result of osmosis, extra salt in your blood sucks water out of your cells. The other article went on to say that you pee out the water that has been sucked out of your cells.

From your article:

Quote

Researchers studying a simulated space flight noted that the body also regulates sodium concentration by retaining and expelling water in weekly and even monthly cycles.

This is what I was referencing. Homeostasis requires some careful balancing of salt to water for interaction with many chemical compositions. It will take water from the cells and then send a thirsty signal to the brain.

When you pee out the water, your body is getting rid of the excess salt that caused the imbalance that leeched more water to flush it out with (). Your mouth goes dry, you start licking your lips, and you really want to get a drink ASAP. 

Technically, osmosis is the mechanism that sucks water from the cells, not the result. 

I think this is the study your article references: https://www.nih.gov/news-events/nih-research-matters/how-body-regulates-salt-levels

[tim.tdj]

Hi Phi

Thank you very much for your reply.

Correct me if I am wrong but what you generally seem to be saying is that salt has a tendency to dehydrate you. Am I correct?

Is it perhaps the case that there are some circumstances when salt dehydrates you and other circumstances when salt aids hydration?

[Phi for All]

53 minutes ago, tim.tdj said:

Correct me if I am wrong but what you generally seem to be saying is that salt has a tendency to dehydrate you. Am I correct?

It technically dehydrates only if the salt to water ratio is too high, is what I read. If you have a high salt intake, you'll retain more water to compensate. If you don't drink enough, the body will siphon it off from the cells to maintain chemical equilibrium. I think it's more about the balance than the leeching effect of salt.

1 hour ago, tim.tdj said:

Is it perhaps the case that there are some circumstances when salt dehydrates you and other circumstances when salt aids hydration?

Again, since the equilibrium is critical, if your body needs the salt but doesn't have enough water to satisfy homeostasis, you'll get several prompts regarding thirst. It seems to me that the study from your link shows that the cycle is more of a weekly or monthly event in regulating sodium concentration rather than hourly or daily, suggesting it's to give us time to find water so the cells don't get robbed. Does that make sense? So yes, salt can aid hydration by making us aware of a thirst.