Common Sense Hydration
by Dr. Eduardo Dolhun
I am a practicing family physician. A family doctor is trained to see all types of patients: the very young to the very old. We treat individuals, families, and entire communities. Since becoming a board-certified family physician in 1999, I have gotten to know humans in health and illness in all sorts of settings. I have treated pregnant mothers, infants, world-class athletes, teenagers, young adults and old adults (the oldest person I have treated was 106 years old). And I have seen patients in cities, suburbs, remote areas, here and all around the world.
What has been a constant theme in the many patients I have seen over the last 2 decades is the important and critical role hydration plays. Proper hydration can greatly assist in recovering from a malady, whereas poor hydration can not only complicate other disease processes, it can alone lead to significant suffering (morbidity) and even death (mortality).
Clearly hydration is important, but it was not until I was in private practice that I began to understand how much more difficult it was to rehydrate my patients at home (orally) than inside the hospital (IV)
Like most of my patients I seemed to get most of my information from commercials, magazine ads, the occasional blog post, the local trainer, and the multitude of products on the shelves in the store telling me how dehydrated I must be and that I had to drink. And the more I drink, the better I am told.
And it sort of makes sense, in an understandable if flimsy sort of way. The prefix of hydration is “hydro” which means water. I was taught to measure the hydration status of my patients as a medical student by serially weighing them, sampling their blood and urine, and taking their blood pressures. These are all fairly easy things to get in a hospital setting but most impractical outside the walls of the hospital. In fact, it is nearly impossible to have a pre-morbid (pre-food poisoning weight) which then can be referenced to the weight when the patient comes in to see me in the clinic or even the hospital. And the same goes for blood pressure and the various blood and urine measurements.
So I quickly learned that assessing someone’s hydration status in real life-outside of the hospital-was a gestalt, a general feeling, based on how long they were sick and the relative amount of fluids lost through sweating, vomiting, and urinating. Trying to assess hydration status on anyone other than a hospitalized patient or someone in a clinical trial was really uncertain, and educated guess, at best.
Yet, that’s not how it feels. We are constantly reminded by advertisers, trainers, and doctors alike about the importance of hydration.
Without knowing whether we are truly dehydrated and what the cause is, are the recommendations to "hydrate, hydrate, hydrate" sound?
I began to look into this deeply about a decade ago and found out that what we, as a society, have been right…and wrong. In order to explain this, I need to explain some physiology. Getting basic and simple can sometimes help a confusing situation.
All of our cells are bathed in salt water. The balance of sodium and water is one of the most important functions of our body. It is so important that the body keep a very narrow concentration of salt in the blood. If we ingest a lot of salt, it is then stored in the bones, connective tissue and the skin for later use. Normally, and despite what we are told, this has very little impact on our blood pressure. The salt is simply added to our bones, making them stronger, in fact, and making the salt available for situations when the blood sodium is too low.
What happens when I drink plain water?
It is quickly absorbed into the blood stream, temporarily addressing my thirst. And that’s fine up to a point. If I go on to drink, say a liter, I then lower the concentration of sodium in the blood. This does several things to the body, none of which we perceive. The body senses a fluid overload by chemoreceptors in the brain and by stretch receptors in the heart. Yes, the heat chamber actually expand.
This situation leads to two things:
- increased urination
- bone loss
I am sure most everybody can relate to drinking a large amount of water and then having to urinate about 30 minutes later. The bone loss is much more insidious, but with potentially severe long term consequences, which will not be covered in this blog.
Now you know, in general terms, enough physiology to understand the historical background that has lead to the current recommendations we have today.
About one hundred years ago, doctors understood that in order rehydrate someone you needed both water and salt. Attempts were made to formulate both IV (intravenous) and oral solutions and IV won out for most of the 20th century. Doctors, especially in the US, became very good at IV hydration. Ironically, IV hydration acquired a near mythical status due association of rapid relief after administration.
It wasn’t until years later, after giving hundreds of IVs that I finally came to realize that the most important attribute of a saline IV is that it has a lot of salt. I see and feel the heaviness of the IV bag, but without the invisible salt dissolved in it, it would not only be useless, it would be lethal. In fact, the root word of saline is “sal,” which means salt! This is quite a contradiction to the current popular culture which advocates low salt everything. Despite what is being promoted sodium may actually not be the nasty mineral we have been told.
Maybe salt is a hidden hero?
IV’s have a definite role in healthcare yet there are drawbacks: they need skilled labor to administer, they are painful, they can cause infections, and they cost a lot.
For these reasons, doctors and scientists began looking at a more simple, effective and low-cost way to rehydrate patients. The breakthrough came in the 1960’s with the discovery and development of oral rehydration solutions (ORS). The solution—a basic combination of salt, sugar, and water—has been credited in saving over 65 million young children since being made available in 1980. Today, it is considered one of the top three medical intentions of modern medicine, along with antibiotics and vaccinations. And of the three, it is the only one that can be administered by anyone, a caregiver or even the patient herself.
It was the basic proven science behind ORS that lead to the advent of sports drinks. Today, instead of calling the most important ingredient “sodium,” we tend to call it and “electrolyte” because of lingering uncertainly about the so-called toxicity of salt.
In any event, it was salty water (with a little bit of sugar) that got the whole hydration craze started in the US. A decade or so after Gatorade launched, it changed its formula, decreasing the sodium and increasing the sugars.
One of the reasons for this is that higher sodium containing drinks with sugar generally taste awful. If you wanted to rehydrate the millions of people who were bering turned on to running in the mid 1970’s, you needed to make something that tasted good.
Sports science started to grow and a lot of research was done on exercise and rehydration.
One of the main areas of emphasis was avoiding heat-related illnesses. These conditions are especially noticeable in new athletes, overweight individuals, individuals pushing themselves beyond their limits, etc.
One area of society that had these very at risk individuals was the US military. They have to take previously out of shape men and women and turn them into combat soldiers, usually in a short amount of time. Intuitively, they focused on hydrating to meet and replace the fluid lost by sweating.
The science conducted on hydration and heat-related injury was put into action in the 1980s and 1990’s and what happened was good…and bad. There was a noticeable decrease in heat stroke, heat exhaustion, etc. but there was an increase in what is now termed exercise-associated hyponatremia (EAH).
What was happening was that we were over-hydrating soldiers and their blood-sodium levels fell to dangerous levels. In fact, in 1999 the first recorded case of a death due to hyponatremia was published.
What was previously thought to be dehydration in the military and in sports, may actually be hyponatremia.
They share a lot of the same symptoms:
- mental status changes
It turns out that there has been no record of anyone dying from dehydration but, rather, low blood sodium.
So, what are we to recommend?
If you want to hydrate in a truly smart way, don’t drink water alone.
In fact, drinking an extra glass of water with your meals is a good strategy, as almost all food has some salt and, as you have learned, if you want to properly hydrate you have to pair salt and water…at the same time. Remember, an IV is just a bag of really salty water.
By all means hydrate, but don’t overdo it and if you are working out for extended periods or in hot weather, make sure your hydration products have appropriate amounts of salt, the invisible hero.