Hydration Is Important - Drink Drink Drink Why?

[futurehope]

Frequently I hear on this forum and also from doctors, to drink. We tend to be dehydrated. I know I am mildly hypovolemic because of a nuclear blood test used to determine that. The problem is, I can't see how that can be useful?

We're hypovolemic because something ("our thermostat" or whatever) is malfunctioning. That's why we're thirsty much of the time.

If that's the case, won't overloading with fluid just make us urinate more and make us potentially MORE hypovolemic than if we had not drunk to begin with? I'm saying this because our "fluid thermostat" is broken and no matter how much we drink, logically speaking, we do not hold on to it. We're malfunctioning.

Now, if we fix the broken "fluid termostat" via some medication or taking the correct amount of salt and possibly taking fludrocort, maybe then we can hold onto fluid. See what I mean?

I brought this up because many of us, me included, drink more fluid without using something extra to make our bodies hold onto it. And, potentially, we could be making ourselves more hypovolemic because the increased fluid intake makes us urinate more.

[firewatcher]

I sort of question this myself, so I'll give it a WAG.

It's like pouring water in a sieve, you've got to keep pouring! By constantly replacing the lost water, you are keeping your blood volume up<>and you have to continually keep adding because it causes you to continually lose it through urination. Catch 22. If you do nothing, your blood volume will continue to drop slowly, ever increasing your blood's viscosity and making you more susceptible to blood clots and organ damage due to lack of perfusion.

The problems come in when your electrolytes go wonky:

Too much water and not enough sodium(low serum osmolality)=hyponatremia and hyperkalemia, bad news!

Too little water and too much sodium(high serum osmolalityy)=hypernatremia and hypokalemia, bad news again!

HYPONATREMIA:low sodium

Symptoms of hyponatremia are related to the severity and the rate at which the conditions develop. The first symptoms are fatigue, weakness, nausea, and headache. More severe cases cause confusion, seizure, coma, and death.

HYPERKALEMIA:high potassium

Hyperkalemia affects the heart and causes electrocardiogram (EKG) changes, ventricular fibrillation, and cardiac arrest. Other symptoms include tingling in the extremities, weakness, and numbness.

HYPERNATREMIA:high sodium

It is associated with the same symptoms as hyponatremia, and also causes the following: Delerium, Irritability, Muscle twitching

HYPOKALEMIA:low potassium

Symptoms of deficiency include cardiac arrhythmia, muscle pain, general discomfort or irritability, weakness, and paralysis.

[futurehope]

You're proving my point. When doctors send home diabetics, they are continually testing themselves to see how their blood sugar is doing.

With us, they send us home with recommendations of fluid loading and salt and they frequently do no testing to see how we are doing?! How many people on here inadvertently create another problem by pushing fluid and sodium? I know we cannot answer.

But, I will bring this up with my doctor and ask him if there is some "test" whether formal or informal to see if a new problem arises (the ones you mentioned). Thanks for the info you posted.

Edited July 17, 2009 by flop
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[flop]

Luckily because our kidneys function normally if we take too much sodium (salt) our body will get rid of the extra in the urine (so long as you keep drinking!). The kidneys are very clever at getting rid of excess salt but they are not so good at holding onto salt when our levels are too low. Fludrocortisone works by making the kidneys hold onto sodium. Where sodium goes water will follow (osmosis).

You can get your blood tested for Urea and Electrolytes (sorry don't know what the US name for the test is). This will show the levels of Sodium and Potassium in the blood. However that test tells you nothing about whether you are eating enough salt to help raise your BP.

To assess if you are taking the right amount of salt you need to get a "24 hour urinary sodium" test. The result should be more than 170mmol/24hours sodium excreted.

The urine test shows how much "extra" sodium our kidneys are flushing out during the course of the day. (A "spot urine sodium" is no good for us). If you are taking in enough salt then the kidneys will be pushing out more than 170mmol. This info is from a study done by Prof Hainsworth in the UK. He found that people who's 24 hour result was less than 170mmol felt better and had a higher BP if they started supplementing sodium at 6grams/day. My cardiologist uses that info to turn it into a monitoring test. If my results come back less than 170mmol/24 hour he tels me to increase my salt intake. If the result comes back more than 220mmol/24 hr he tells me to reduce my salt intake. I do the test about every 6 months to guide my salt intake.

Flop

[futurehope]

Thanks Flop. I really appreciate the info. It makes more sense to me to test and see how well our bodies are using what we supplement with. I'm going to show my doc your info. I think it's wonderful that there is a study out there showing how much sodium we're supposed to see in the urine in order to get the best benefits.

It makes way more sense to me than just plan guessing, KWIM?

Edited July 17, 2009 by flop
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[heathmcev]

Thanks for posting this futurehope. I have been so frustrated with having to pee every 15 minutes from drinking so much liquid, yet feeling thirsty at the same time! One of my non-POTS docs recommended a urine electrolyte analysis, but flop's system really seems to make sense. I'm going to google Prof Hainsworth's study to show my neuro (if anyone has a link to post for it, would be much appreciated... I'll post it if I have success finding it.)

[flop]

Hi, I've found the article I was referring to above. The reference for it is:

?Salt Supplementation Improves Orthostatic Cerebral and Peripheral Vascular Control in Patients with Syncope? V. Claydon, R. Hainsworth Hypertension. 2004 ; (April) 809-813.

And you should be able to get the PDF document here.

The article is also availabe to view online on this website.

Flop

[futurehope]

Thanks for the link.

I just noticed the article references postural syncope. I wonder if the salt loading helps POTS as well?

Flop, do you have POTS? Do you suffer syncope? Thanks.

[firewatcher]

I am going to throw in a word of caution to this: make sure your renal function is "normal" and extra salt is not a bad thing for you.(some of us are hypertensive!)

My kidney function has steadily declined over the last year and none of my docs know why. They have cautioned me against florinef until I know. I was thought to have Central Diabetes Insipidus, but that was proven wrong through a formal H2O deprivation test, but that finding is again in question. Salt is good if you can get rid of the extra...as long as your kidneys work!

The perfectly normal human kidney can safely handle up to 14 liters of water a day without electrolyte derangement. Medications that change that will vary the amount you can drink.

I am on dDAVP, which causes me to retain water but not sodium...so if I drink more than four liters of water or juice a day I will become hyponatremic. I have an outlet, or dump time between doses to lose the extra water, and my plasma sodium goes up REALLY fast during this time, almost as fast as me running to the bathroom!

In all my testing, not once has any doc measured my urinary sodium excretion. You would think it might tell them something.

[futurehope]

Good point about kidney function. I wonder if doctors routinely test for kidney function before they suggest additional salt and water?

[janiedelite]

Flop, thanks for posting the info on salt intake! I have high BP with standing (sitting too, even talking) but it seems the more salt I consume the more normal I feel. My BP even comes back to baseline. I haven't found an upper limit. Today I probably consumed about 7 grams of sodium along with 5 liters of fluid because I knew I'd be doing a lot. I feel pretty decent this evening considering all I did today! My kidney function has always been great, and I have had low urine sodiums before which Mayo said was from dehydration.

Without the salt, though, it is like a sieve and I feel like I need to pull a port-o-potty behind me wherever I go...

[ramakentesh]

FOr me the trick is to drink quicker than you can urinate I urinate a lot. Im in the toilet at work more than the bloke with uncontrolled diabetes II.

[futurehope]

I wonder if the increased sodium over time can cause other problems such as stones, or malfunctioning kidneys? Another question for the doctors.

[potsgirl]

My kidney functioning goes up and down, so I have it checked every 4-6 months. My nephrologist is sure that it's caused by my low blood flow to my organs. I also had to have my gall bladder removed, and my doctor thought my low blood flow probably also contributed to that.

Cheers,

Jana

[futurehope]

Potsgirl,

Yikes!!!! So much for whether POTS can be more serious or not. I consider damage to organs pretty serious.

I'm sorry to hear about your malfunctioning organs. Is your blood flow so poor that the doctors suspect hypoperfusion?

Maybe some of us should be thinking along those lines as well?

Take care.

[EarthMother]

I can't increase fluids as typically suggested unless I am taking DDAVP ... otherwise I not only seem to pee it all away, but it seems to over activate my kidneys and I tend to lose MORE body fluid than I am taking in.

Some dozen years ago (when we just called it idiopathic orthostatic hypotension) my endo discouraged me from drinking water (in volume) because I was flushing out my electrolights. (Strange, I think I was even on florinef at the time.)

In later years I drank copious volumes of gatorade. Ended up with systemic candida -- my Doc and I became convinced it was the sugar content in the sports drink.

I only take DDAVP now if I am dropping weight. So I don't drink the volume some folks do. I do tend to salt tho, because it helps me keep IN what I do drink.

[flop]

futurehope - I have both POTS and syncope (NCS).

Low urinary sodium shows that your kidneys are actively reabsorbing as much salt as possible from your urine, this is because by retaining sodium you also retain water. So yes Mayo are right that low urine sodium in your case is probably due to dehydration. The caveat is that without enough salt you can't correct the dehydration.

It is important to get the fluid and salt balance right for your body. Everyone is different and will need different amounts of fluid and salt. Getting your kidney function checked every 6 months is a good idea (you need urea and creatinine mesuring).

The way that my cardiologist uses the information from Prof Hainsworth's study is to check if I am taking too little or too much salt. We try to keep my urine sodium at 180-220mmol/24hours.

Salt shouldn't cause kidney stones as they are usually made up of calcium oxylate (80% of kidney stones) or uric acid (10% of stones).

To maintain optimal kidney function you need to get the water and salt balance in your body right so that you have good blood flow to the kidneys without excessive work from massive salt ingestion. This is where the 24 hr urine test is so helpful. If you are passing more than 220mmol/24hr of sodium you should probably cut back your salt intake.

Flop