Beware of Water Intoxication

18 February 2004:

Some books written by doctors (M.D.s) are dangerously flawed, like proposing salt free diet without warning against iodine deficiency. Frankly, they do more harm than good. That's because when they have a M.D. behind their names, their writings tend to be dogmatically followed. As a result, if they do not warn of potential side effects, especially the untrained laymen would have no way of avoiding them. For instance, one such book advocated 10 glasses of water per day which is way beyond what is necessary or safe for lots of people. In fact, it could cause water intoxication in some.

Increasing water intake does not necessarily prevent constipation. As we all know, people can be so diarrheac as to go in to dehydration or shock. How much water is in the system (in the body) has no effect on the frequency or quantity of the bowel movement. Likewise, if the rate of the bowel peristalsis is otherwise too slow, pushing water into the body is not going to relieve constipation. Why? Well, experimentally it has been proven that in that situation the water absorption in the large intestine would be at the same as when there is no water pushing and therefore the stool would be as hard or solid as at lower volumes of water intake. At the same time, on the other hand, even though there is a lot of water being pushed into the stomach, when the bodys cell and extracellular tonicity has already been lowered too much by excessive water intake, there wont be sufficient direct water entry into the portal veins, and it remains in the stomach for longer periods of time than usual. Thats when a person starts to suffer nausea or vomiting, or the stomach starts to froth up water, signs of water intoxication. If bad enough, there would be stomach cramps, stomach churning, reverse peristalsis up to the pharynx,1 gastric efflux, or even worse. Actually, the first signs of water intoxication is difficulty in water emptying from the stomach. If half an hour after drinking a glass of water the stomach remains full and the water appears to go nowhere, suspect excessive water intake. Excessive pure water intake still gives hardened stool while adding vomiting and stomach churning, or even worse things to your sufferings.

It's not good enough to say that a 120 pound person should have six glasses (or about 4.6 large tumblerfuls ) or about two litres of pure water per day. This may be safe for someone actively walking about with healthy kidneys to excrete excess water from body in warm weather, but perhaps unsafe in cold winter in a sedentary individual not active enough to bring about sufficient water filtration and excretion to maintain a physiologically normal body water balance. See, only when a person is active enough would there be enough times of blood circulating through kidneys for sufficient filtration to occur. If the blood does not circulate through the kidneys enough times per day, therell be insufficient filtration and therefore insufficient urine output per day. Water intoxication can then occur if water intake is not proportionally reduced. Even for people with normal kidneys, in cold winter a 120 pound sedentary individual should take in only half of the above normal volume, that is, three glasses per day. Similarly, on the other hand, if a person is doing vigorous exercise in a hot weather, way in excess of six glasses per day would be needed.

19 February 2004:

In this respect, in as early as 1958 when I was a primary school pupil in China the advice given to us by our teachers was to replenish fluid lost in sweating with salt water, not salt-free water. This stands to reason because there is a lot of sodium lost in sweat. If huge quantities of sodium lost are not timely replenished, hyponatremia might set in. This is analogous to the normal intravenous infusion of saline solution rather than pure water dripping which would cause dangerous hypotonicity. So, while thinking about salt restriction to reduce blood pressure, dont forget that sodium must be sometimes artificially introduced into the body as sodium ions just to maintain electrolyte balance. Do not push salt restriction to the extreme only to create dangerous or fatal electrolyte imbalance. Salt free doesnt and is not allowed to mean salt free under all circumstances.

18 February 2004:

As a whole, what should we do? Two days ago it was reported on TV that the best maybe to drink when thirsty. Thirst is a normal physiological regulatory mechanism. If we go by it, we cannot be far from being right.

22 February 2004:

Never push water beyond what your appetite and stomach would desire. For instant, because that forgetful M.D. wrote in his book to have people take 10 glasses of pure water every day, no juices, no salt; someone might indiscriminately follow to a very dangerous or even fatal end. For someone with poor circulation or compromised kidney function, or in cool weather and therefore without sufficient insensible water loss through perspiration, or someone with a small body size or low body weight, 10 glasses of pure water daily can cause water intoxication.

Pure water is a hypotonic solution which should be taken sparingly to avoid causing tissue hypotonicity and edema. Unless you are desperately trying to lose weight, there is no reason on earth for you to avoid fruit juices which are nutritious and often essential for maintaining electrolyte balance. As an example, if you have diarrhea, you should drink extra quantities of fruit juices to replenish the potassium ions lost in watery stool. On the other hand, as already mentioned, if you have been sweating profusely through exercise, you should add a little salt in the water you drink to replenish the sodium ions lost in sweat. Furthermore, fruit juices containing potassium ions are at least not hypotonic as is pure water and therefore should pose no danger or less danger than excessive pure water to body electrolyte balance or normal tissue tonicity.

25 February 2004:

For those using soft drinks or alcohol or tea or coffee or any other types of hypotonic fluid, the same caution and restraint must be applied as in using pure water. There is a remedial measure for tea or coffee or even cocoa lovers. Just add a lot of milk powder into your drink to make it hypertonic. See, milk powder contains as much calcium ions as you may wish to add: the higher the calcium ion concentration and therefore the higher the osmolality (and therefore the more hypertonic) the drink you want, the more milk powder you can add into it. By raising a hypotonic tea solution into a hypertonic tea milk solution, you avoid the risk of causing water intoxication.

22 February 2004:

The case of not drinking salty sea water but urine to survive when lost at sea is a reverse situation helping to illustrate the preceding mechanism. Because sea water is too salty, too much sodium ions per litre of water and therefore excessively hypertonic relative to the living cells and tissue fluid, imbibing any significant amount of sea water would cause the cells to shrink. Water is drawn out of the cells and tissue fluid so that the more one drinks, the thirstier one becomes until one dies of dehydration. Pure water, in contrast, is relatively less hypotonic than is sea water hypertonic to the body. Thats why we can usually safely drink pure water and absorb it. However, absorbing hypotonic water like this would be also dangerous if excessive. When excessive, cells would become also hypotonic and swell up in size until they burst. Thats why i.v.(intravenous) solutions are isotonic, having sodium ions to elevate their tonicity to that of the blood. Thats why in such cases sodium ions cannot be avoided. Using sodium-free pure water solutions would be fatal indeed. So dont go around with your paranoia against salt and use salt-free i.v. solutions to have everybody killed. And, pushing excessive pure water intake per os (by mouth) is just a slower form of pushing salt-free water into peoples veins.

23 February 2004:

The safest is to take the daily water requirement not in the form of pure or distilled or river or well or plain water which is hypotonic, but to take it in the form of hypertonic solutions such as juices which can be unsweetened or sugar-free, or whole wheat bran cereals in milk, or soup, etc. The reason there is that when the fluid intake is not hypotonic, there would be no absorption of pure hypotonic water to enter into body tissues to cause hypotonicity there.

22 February 2004:

If you may be drinking too much water (such as after taking water or liquid your stomach wants to throw up, or is doing reverse peristalsis up to your throat, or is bloated, or is causing hiccups, or you are burping excessively,2 or if you are having stomach cramps, or for no other reason your face is puffed up (edema) or there is tissue edema at any other parts of the body and yet not at the ankles: ankle edema often indicates congestive heart failure,3 not just water intoxication) or not knowing how much water or juices to drink, you should see a specialist well trained in acid-base and electrolyte balance, and not just any doctor who may be incompetent in this rather complex area of internal medicine.
"after taking water or liquid your stomach wants to throw up, or is doing reverse peristalsis up to your throat, or is bloated, or is causing hiccups, or you are burping excessively, or if you are having stomach cramps," could also be symptoms of stomach ulcer or worse, stomach cancer. More on the latter later (i.e., in the future). (added 3 May 2006)

19 February 2004:

As already implied, the rate of the intestinal peristalsis, not how much excessive water is taken in on a daily basis, is the only effective determinant of whether we are constipated. And, the most effective means of stimulating intestinal peristalsis include such measures as brisk long walks of one hour or more. Similarly, exercises such as rapid dancing for about 20 minutes or more can be also effective. Once peristalsis is rapid enough, so long as there is no less than two glasses of water every day, how much more water is taken in has little impact on the frequency or adequacy of the bowel movement. Although occasionally drinking a litre of fluid all at once (e.g., apple juice or tomato juice) could induce a bowel movement, chronic overdrinking loses that effect and may just cause dangerous water intoxication. The reason there is that when chronic excessive water intake has already created a hypotonic environment in the body, an additional liter of fluid taken in would no longer be effectively absorbed, just further worsening water intoxication. But if the body has not been given excessive water, it would be isotonic when this occasional liter of fluid is taken and would be able to rapidly absorb it. Now this fluid can exert an effect on bowel movement.

Combat constipation: Finally, other than exercise, the last resort for constipation is prune juice which stimulates intestinal peristalsis beyond what effect its quantity might have on bowel movement. In other words, it is like a medication increasing peristalsis rather than just providing fluid for the body. When prune juice fails, thats when over- the- counter suppositories may have to be considered. Or, see a doctor immediately.


Prune juice4 dosage: The optimal one is 16-24 oz before bed time at night. Too little is ineffective. Too much causes diarrhea. You can try this dosage and adjust accordingly.


1 This experience can be best described as sensing a python constricting from its tail upward all the way to its head which would be our pharynx or the back of our throat. Thats the esophagus doing the reverse peristalsis contracting and twisting upward to cause often unbearable dull pain.

2 Giving off gas in the other direction is always healthy. But when it is given off from the mouth, it could cause upward peristalsis of both the stomach and the esophagus, dangerous indeed. Thats not the right direction of food and stool movement. We want it all to move downward, not upward.

3 JJV McMurray, Heart Failure, Diagnosis and Management, London: Martin Dunitz, 2001, p 52: Ankle edema is more likely to be caused by chronic venous insufficiency than by congestive heart failure, especially in the middle-aged woman who complains also of tiredness and perhaps breathlessness on exertion.

4The use of prune juice to prevent constipation was something I overheard from a nurse who was just telling that to a patient. Therefore I can no longer recall her name. Letts say that was from a Canadian /nightingale.”


27 March 2004:

Diagnostic tips:

1. If there are spots of tissue edema other than at the ankles, suspect water intoxication.

2. Normally, other than the very young children, the skin on the back of our hands when fully extended should show small grooves or wrinkles. But if there is water intoxication, these wrinkles might disappear so that the skin may appear to be smooth, better looking but less healthy.

3. Normally, the veins on the back of our hands and in our forearms do not stand out a great deal, but if there is too much fluid in the body they would prominently stand out. This occurs also if a drink has been hypotonic and a person has drunk a lot of it. If one has taken a lot of hypertonic solution, the veins would not stand out as much.

5 April 2004:

4. One of the easiest ways of telling whether you have taken in enough fluid is the adequacy of various bodily excretions such as tears, saliva, and sputum. If you have difficulty expectorating, that is coughing up the sputum from your lungs, and therefore are constantly clearing your throat to get rid of that flame stuck there, it means that you lack sufficient bodily fluid to keep the sputum wet. You should increase your daily fluid intake to the level when you can easily cough up the sputum.

17 April 2004:

However, the sputum should not be too watery either. When its too watery, it may mean that you are having too much water in your body. So, the best sputum should be colourless, odourless (if coloured or foul-smelling, see a doctor) and viscous though still easily dislodgeable from the lungs.

5 April 2004:

Again, be warned that the would fluid does not stand for water. Instead, it represents here isotonic or hypertonic solutions such as milk, and juices of sufficient tonicity or concentration, or water taken with solid food. But if you can easily expectorate, your sputum would be wet enough to be easily dislodged from your lungs for removal. Your body water is then sufficient. Fluid intake should be maintained at the current rate.

2004(C)Kuan-Chyun Cheng, M.D.,B.A.

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