Water and Health
It is the Essence of Life

Introduction and Overview

Water and health go hand in hand.  Everyone knows we need eight 8 oz glasses of water per day.  Really? Actually that is just a general guideline for the imaginary "average" person.  

Just as no two people are identical, no two individuals water needs are identical; it varies according to many lifestyle factors including level of activity, exercise habits, geography, muscle tone and body fat plus several others.

We have previously defined an essential nutrient as one that our body cannot produce; it must be obtained in food, drink or supplementation.  Since our bodies cannot make water and if we don't consume enough, we will die, it follows that water, in the nutritional sense, must be an essential nutrient.

Morbid obesity showing fat mass

Most people have a water content between 65-70% but the exact percentage has much to do with muscle mass and body fat. 

Since body fat contains little to no water and muscle tissue is about 70% water, we can see that the bodies of an obese person and a muscular body builder who happen to weigh the same, would have a wide difference in water content.

Photos:  Solid muscle and morbid obesity have vastly different water requirements.  Are you top right or bottom left?

body builder showing muscle mass

Typically we lose muscle tissue and gain body fat as we age so our water requirements do change over the years.  This is normally not something we have to dwell on but can be significant if we become hospitalized and need fluids from an intravenous (IV) drip.  Then someone has to calculate our body fluid requirements and will need to take fat and muscle mass into consideration.

Losing muscle mass and gaining fat weight is not a normal aging process; it is more the result of becoming lazy and falling into bad lifestyle habits. 

Muscle mass can be retained by resistance training and exercise and fat can be kept within a normal range by maintaining discipline in nutrition and food choices.  Water and health are directly related.

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What Does Water Do For Us?

Besides quenching our thirst, several functions of the body are related to water and health.  The most important role of water is to dissipate and regulate heat loss.  Concerning heat, it is very similar to the radiator and cooling fluid in our cars. 

Of equal importance is that it transports digested nutrients to the cells in the blood.  The blood then takes the nutrients to the organs, tissues and structures where they are needed.   

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Water also allows for lubrication of the joints.  Think of the synovial fluid in our joints; it has a high water content and, in addition to lubrication, also transports nutrients in and carries waste products out.

Tears are mostly water, as is mucous.  Both are cleansing agents and the removal of foreign material is their main role.

Water Storage in the Body

This seems to be a great spot to be reminded of Star Trek, The Next Generation, episode 17, in which the alien microbrain described humans as "mostly bags of water".  Since the average human body is 65 - 70% water, the alien's description of us is probably justified.  Where is all that water in our body stored? 

The body's water supply is mainly stored in the blood and in and around the cells, but that is in a healthy body.  Where that fluid is stored greatly affects our water and health balance.

What we eat and the condition of our health can redistribute much of that water.  For example, if we do not consume enough protein, the structure of arterial walls can become compromised to the extent that water can leak through the walls and invade the surrounding tissue.  Edema, or water retention in body tissue, resulting in visible swelling is the medical description. 

Water in our bodies is always in motion and our scale weight can change quickly depending on the intake and elimination of water.  If we are edemic (water retentive) or dehydrated, that weight differential can be quite large. 

An adult will normally eliminate 2.5 liters or 84 ounces of water a day.  About 60%, or one and a half liters, will be through urine with the rest being eliminated by sweating, respiration or bowel movement.  Since our breath is 100% humidified, a significant loss of water occurs during normal breathing and more during rapid breathing as during exercise.
Health conditions have an effect on water loss.  Fever and diarrhea are two good examples.  If we have a fever, our body temp goes up and we will lose more water.  Diarrhea is a big source of water loss and if severe, can be dangerous.  We need to understand the water and health relationship.

Water content of Food

If we stick with the guideline of eight 8 oz glasses of water a day as our water requirement, then food consumption would account for about a little over two of those glasses of water.

Fruits and vegetables are the two categories highest in water content, averaging between 80-90% water.  Milk and yogurt also comes in at 80-90% water.  Looking at a few specific fruits and vegetables, fresh carrots have about 88% water, fresh tomatoes about 93% and 94% for fresh celery.  Note the keyword "fresh". 

After vegetables are harvested, they tend to steadily lose water content. The highest are watermelon and lettuce, both having a 97% water content.  Thus, fruit and vegetables can be a critical factor in our maintenance of both water and health.

Looking a meat, lean veal has about 80% water and fully fattened beef about 50%.   

If someone needs huge amounts of water, like a marathon runner, and they just can’t physically drink enough, then food becomes a good intake mechanism for water; more on that in a few paragraphs.  Good clean water and healthy fresh foods will easily keep us hydrated.

Water and Health
Keeping Fluid Balance

Heat and humidity are the two most significant environmental factors that can affect our fluid balance and thus our body water and health.  Sounds logical and it is.  In areas of high heat and humidity such as Florida, Georgia or the Texas gulf coast, we tend to sweat a lot.  It is our body's air conditioner.

In practice, as the sweat evaporates, it carries away heat.  In areas of high humidity, however, the sweat doesn't evaporate so we don't get cool and the body's reaction is to make more sweat.  This obviously depletes the body's supply of water and health will deteriorate fast if not replaced.

Cold weather can also be dehydrating but the mechanism is very different from a heat induced sweat.  In a cold environment, we still lose water through our skin but may not drink enough since we do not get the sensation of sweating that triggers the thirst mechanism. 

If you have ever been a long-distance air traveler, you know that pressurized cabins at high altitude can really contribute to fluid loss.  Starting out, a pressurized cabin in an airliner has no humidity; it is zero. 

Consider that our breath is 100% humidified. When the plane lands, some experts estimate that the humidity has risen to  about 40%.  The only place it can come from is people's breath.  Considering water and health, no wonder airliners are great for transmitting air-borne germs via the cabin moisture. 

Thus the flight attendants are frequently coming around with bottled water and advising us to drink.  At least they used to.  We wouldn't be surprised if the free bottled water has now gone the way of the snack tray on commercial flights.

Don't expect the Transportation Security Administration to let you bring your own bottled water on board so bring a wallet full of bills to buy your hydration.

Assessing Hydration Levels

Aside from feeling thirsty, how do we test our hydration level?  The color and volume of urine can be pretty good indicators or how well we are doing keeping properly hydrated and looking after our water and health.

If your first urination after crawling out of bed in the morning is light yellow, perhaps the color of pale lemonade, chances are you did a good job of hydrating yourself the day and evening before.  If it is darker in color, like apple juice or darker yellow, and the volume is smaller than usual, then you didn’t drink enough the day before.  If it's red, purple or black, you should probably be in the emergency room.

Most people would assume that thirst is a good measure of hydration but they would be wrong, or at least late. Thirst is not a very good indicator because there is a lag between the time we get dehydrated and actually feel thirsty.  There is a common saying that has a lot of truth to it, "if you are thirsty, you are probably already dehydrated". 

Aging tends to dull the thirst mechanism and this can become very serious to elderly nursing home patients.  They run the risk of dehydration because they don’t feel thirsty and if taking medications, complications can easily occur.  Water and health must be closely monitored in an eldercare setting.

Regarding medications, pain meds can blunt the thirst mechanism so if taking regular pain pills, be sure to keep up your water intake.  Even Someone on an IV drip will still need water.  Of course diuretic meds will cause thirst because their whole purpose is to remove water stored in tissue to relieve edema.  In this case, follow your care givers instructions on how much water to drink and when.

Another good reason to keep properly hydrated is that it tends to prevent kidney stones.  If you have ever had a kidney stone or know someone who has, it is unforgettable and and an experience you won't want to repeat.  

The mechanism is pretty simple.  When urine becomes very concentrated, small crystals form that eventually become stones, literally rocks and very jagged rocks at that.  The pain is intense and is usually situated in the lower back and side, especially when one urinates.  Fortunately, prevention is also simple, drink lots of water to keep the kidneys flushed out and those little crystals won't form.

The Mayo Clinic has kindly put up a wonderful internet site that will tell you everything you ever wanted to know about kidney stones. Just go to Kidney Stones and you will soon be an expert.

Exercise Effects on Water and Health

When it comes to exercise, the only way to accurately tell what is going on with your hydration is to get on the scale.  Water is heavy.  A gallon of water weighs 8.35 pounds, a liter of water weighs 2.2 pounds or one kilogram.

Use the scale to assess water loss

So if you weigh yourself at the start and end of a race and discover that you lost four pounds of body weight, you can be sure that it was all water; a little over two quarts to be exact.  In the time it takes to run that race, there is no way that any of that weight loss was fat.

Water and health matter greatly to athletic performance.  A 1 - 2% decrease in body weight through water loss, will decrease an athlete's performance by 15-20%.  So if you want to enhance your performance on the field, don't take steroids, drink water;  it is a legal, performance enhancing, sports drink.

From the American College of Sports Medicine, we learn that if exercising less than an hour at moderate intensity, water is all that is needed.   If we go all out and exercise more than an hour or in the heat or at a very high intensity, then reach for the Gatorade or other "sports drink".  

Sports drinks are for sports, only to be used during sports or strenuous extended activity.  They are not intended to be a lunch time drink.  Their main function is to replace lost electrolytes, particularly sodium that is lost through sweat. 

For some reason, it has become common to try and replace potassium after strenuous activity but potassium losses due to exercise are minimal.  It is the sodium loss that causes the cramping of muscles after physical exertion.

We can calculate our sweat rate to determine how much water is lost during hard physical activity.  Sweat rate is just a phrase for how many pounds you lost during physical activity.  Each pound lost represents 16 ounces of sweat.  To To replace that fluid, or rehydrate, we need to consume 16 to 24 extra ounces of fluid.

It’s not a matter of 16 out and 16 in since some is lost through urine and the objective is to rehydrate the muscle.

An athlete losing 10 pounds during the big game, has lost 160 ounces of sweat or twenty 8 ounce glasses.  If he only gets eight 8 ounce glasses to replace the lost fluid, he will be significantly dehydrated and his performance will suffer.

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Over and under hydration

There are definite signs and symptoms of dehydration.  Weight loss, confusion, a dry skin that is hot to the touch, and an elevated core body temperature are all signs of dehydration.  The latter is a medical emergency that can cause death. 

A function of water is to dissipate heat and if we lose such an amount of water that heat cannot be dissipated, then core body temperature rises; it can’t do anything else.  Our normal body temperature is 98.6 degrees and core temperatures over 106 can kill us.

Some readers may recall the October 2009 sweat lodge incident near Sedona, Arizona in which 50 people were placed in a makeshift sweat lodge for two hours (normal time for a sweat lodge ceremony is 40 minutes). 

When it was over, three people were near death. Eighteen others suffered burns from hot steam, dehydration, respiratory arrest or kidney failure.  Some participants began to appear ill after about an hour and two of the participants died that night and the third went into a coma and died a week later.  Anyone still think water and health aren't linked? 
Rehydration through drinking is best but if the dehydation is severe, an IV may be needed.  Our stomach and intestines can only handle 1-2 liters at a time so if someone lost more than that, oral rehydration will not reestablish balance.
Over hydration means taking in more water than you can possibly need.  Fraternity hazing has killed kids from forced water intake because the sodium level in the body gets so diluted that cerebral edema (swelling of the brain) occurs which can cause death. 

Neophyte runners often over hydrate themselves also diluting their sodium blood level.  The term for this is hyponatremic, literally, "not enough sodium in the blood".

If a runner weighs two pounds heavier than when he started the run, it means he drank two more pounds of water than he needed. It is a medical emergency if someone drinks more water than is needed.
It should be clear by now that water and health go hand in hand.  For discussions on various aspects of water and health in our the environment and the sources of tainted water, click on any of the links below.

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