The Importance of Hydration

Yes, simple H2O is the single most important nutrient the human body needs, and here’s why.

What Really Makes Us Thirsty?
Webster’s’ Dictionary defines thirst as “A sensation of dryness in the mouth and throat related to a need or desire to drink.“ When fluids are lost, there is a steady increase of sodium in our blood.

“Sodium being the electrolyte responsible for fluid retention, holds the key as to why we thirst,“1 as states. An electrolyte is a “medical/scientific“ term for salts, specifically ions. The term electrolyte means that this ion is electrically-charged and moves to either a negative (cathode) or positive (anode) electrode. Throughout the day, whether active or not, there is a gradual reduction in our bodily fluids from chemical reactions, including exercise of all types. When this concentration reaches certain levels, the thirst center in our brain is triggered, creating a sensation of thirst.

Guyton’s Textbook of Medical Physiology states that “the total amount of water in a man of average weight (70 kilograms) is approximately 40 liters, averaging 57 percent of his total body weight. In a newborn infant, this may be as high as 75 percent of the body weight, but it progressively decreases from birth to old age, most of the decrease occurring during the first 10 years of life. Also, obesity decreases the percentage of water in the body, sometimes to as low as 45 percent“.2 It is important to note that these figures are statistical averages, and will vary with based on the type of population, age and number of individuals sampled, as well as the methodology. Consequently, there cannot be a figure that is exactly the same for all people.

Decreased volume in the intravascular compartment is called hypovolemia. Because water moves freely between the compartments, extracellular fluid deficit causes intracellular fluid deficit (cellular dehydration), which leaves the cells without adequate water to carry on normal function. Water is also reported to be in part, “responsible for the transmission of light and sound in the eyes and ears.“3 Water is an important element of synovial fluid particularly in our joints as illustrated in this knee photo from

Having personally gone through 21 procedures to my right knee, over 19 years, I’m sold on good joint care for everyone, particularly the elderly.

Commercially Bottled Water Basics

Americans spend billions of dollars every year on bottled water. People choose bottled water for a variety of reasons including aesthetics (for example, taste), health concerns, or as a substitute for other beverages. If you have questions about bottled water, make sure you are informed about where your bottled water comes from and how it has been treated. The standards for bottled water are set by the United States Food and Drug Administration (FDA), which bases its standards on the EPA standards for tap water.

Our body’s average daily loss of fluids through excretion, respiration, chemical reactions and perspiration varies from 1 to 3 quarts. “If you’re on a high protein diet you may need more fluid intake than the average person for digestion and nutrient absorption.“4 This was explained to me while training with a California Doctor friend and has become my personal practice. I take in approximately 2 grams protein per pound of body weight daily when training to add muscle. This has worked great with me as I continue to gain strength, add lean muscle and keep body fat low. I supplement this with about one gallon of water daily per my Doctor’s approval. I’m 6′ 1/2“ at 206 pounds and 8.8% body fat. And, oh yes, I’m 60 years old.

“Current practical guidelines identify a loss of 2% of body mass as the level of dehydration at which performance impairment is likely to occur.“5 This guidance is reflected in a 2005 scientific consensus statement issued by the American College of Sports Medicine.

My personal experience with current clients leads me to believe this may be higher in certain training activities, such as boxing, Muy Thai martial arts or racquet ball. These activities obviously cause our body temperature and heart rate to increase, pulling water away from reserve sources in an effort to maintain critical blood volume and safe temperature. By simply watching my clients eyes and facial expression I can tell when they’re running out of energy, need water or “tapping out“ as I fondly say. I never train anyone to complete failure! This, in my world, as a Master Fitness Trainer is unacceptable.

Water is Cheap Insurance

This information from pure further illustrates this article’s point further;  “One of the easiest ways to help the body function optimally and remain disease-free is to keep it well-hydrated. In drinking sufficient water throughout each day, we assist our body’s ability to flush toxins and metabolic waste. Most healthy adults need not worry about over-hydration.“6 This last line from above quote hopefully will hopefully inform those of you who have told me over the years, “I drink too much water.“ Research has shown chronic dehydration to be the root cause of many diseases associated with aging (e.g. arthritis, G.I disorders, senile dementia). To complicate the situation, our “thirst signals“ decline as we become accustomed to being dehydrated and as we age.

Don’t count on coffee or sodas to achieve a daily hydration goal. Because of the caffeine in coffee and most sodas, you need to consume at least the same amount of water just to break even. Sugar content in sodas exerts great osmotic pressure; water is lost from the blood to make the soda dilute enough to leave the stomach. Every breath we exhale is always 100% humid. It does not matter what the relative humidity is that day; generally in air-conditioned buildings , the air is about 10% humid. The difference comes from our water reserves.

Perspiration is not always noticed in dry climates because it wicked away before it can bead on your skin. Even though you may not see it, be assured that you are certainly losing fluid reserves through sweating.“

I was extremely please to have found the following information on the Centers For Disease Control(CDC) home page;

  • For basic information on bottled water, see the EPA’s brochure on Bottled Water Basics
  • Read the label on your bottled water. While there is currently no standardized label for bottled water, this label may tell you about the way the bottled water is treated.
  • Check the label for a toll-free number or Web page address of the company that bottled the water.This may be a source of further information.

The National Federation Professional Trainers Master Fitness Trainer manual states, “Water is generally absorbed into the small intestine at the rate of 8 to 10 ounces every 20 minutes and should be ingested before, during and after elevated periods of physical activities. Cold water enters the small intestine faster.“7 For me, this works best and quenches my thirst quicker.

I trained many clients in the Palm Springs, CA area for eight years, where summer temperatures would reach 120 degrees. The ongoing need for hydration was critical in this environment. It was my responsibility as a professional trainer to keep my clients aware of their bodies’ hydration needs. In such extreme temperatures, poor hydration can actually be fatal in a short period of time!

One of my suggestions is to weigh in before and after exercising. Then, drink 16 ounces of water for every pound you lost during your workout. Never take in large amounts of sodium during exercise! This may well result in severe cramping and possible heat stroke or exhaustion. This is ironic for me today, as while in boot camp in 1972, we had to take salt tablets before running in 100 degree plus temperatures. There were guys falling out, fainting and getting rare cases of heat stroke. Point proven, I’d say, pertaining to the sodium intake! In my personal workouts, which are intense, I use a 24 ounce carb drink mixture containing 6 % sugar diluted with 50% water. I advise drinking at least 16 ounces of fluids within 30 minutes of any competition like running, cycling or swimming. Sweat rates vary, so get familiar with your own need for hydration.

The National Federation of Professional Trainers advises us to “stay away from amino acid supplements during the hydrolysis process. Some of these supplements have been found to be compromised and therefore useless. These tainted supplements could, in rare cases, include toxic by-products from processing.“7 This is not meant to scare anyone but it is intended to make you more aware of the things going into your body and possible complications. I constantly ask my clients “Do you need water?“

One of my training requirements is to “bring your water bottle“ for reasons stated in this article. It is very important, folks! Even if you run outdoors in a cold climate the same need goes for adequate hydration. Even in air conditioned fitness facilities, we need to be vigilant with fluid intake. In her article, What and when athletes drink depends upon exercise duration and intensity,, Elizabeth Quinn discusses hydration for “athletes.“ My experience indicates the same basic hydration needs apply for those of us less athletic

Proper Hydration for Exercise – Water or Sports Drinks

Athletes need to stay hydrated for optimal performance. Studies have found that a loss of two or more percent of one’s body weight due to sweating is linked to a drop in blood volume. When this occurs, the heart works harder to move blood through the bloodstream. This can also cause muscle cramps, dizziness and fatigue and even heat illness including:

  • Heat Exhaustion
  • Heat Stroke Causes of Dehydration

Causes of Dehydration

  • Inadequate fluid intake
  • Excessive sweating
  • Failure to replace fluid losses during and after exercise

As a long-time fitness professional, I have never experienced any form of hydration +/- issue, and I don’t want anyone else to. It is my sincere hope that those of you weren’t savvy to hydration urgency in your body have been helped.

Bill McGinnis is an NFPT-certified Master Fitness Trainer, and trains exclusively at the University of Texas Medical Branch Alumni Field House on Galveston Island, TX. He has over 24 years in the Fitness Industry, including work as the Men’s Fitness Trainer at the Betty Ford Center and as a Fitness Manager in Southern California. He currently specializes in training older clients for balance, strength, endurance, golf, tennis and an improved quality of life. 


2. Guyton’s Textbook of Medical Physiology. Arthur C. Guyton., John E. Hall;
4. Personal Correspondence.
5. The American College of Sports Medicine. 2005.
7. Master Fitness Trainer Manual. The National Federation of Professional Trainers.
8. What and when athletes drink depends upon exercise duration and intensity. Quinn, Elizabeth. Guide. Updated June 30, 2009

Bottled Water Basics. . September 2005. EPA.


Bill McGinnis is an NFPT Master Fitness Trainer. He lives and trains in Galveston, Texas and works at the University of Texas Medical Branch Alumni Field House. Bill previously served at the Betty Ford Center in Rancho Mirage, an internationally acclaimed rehab facility for substance abusers and persons with eating disorders, as The Men’s Fitness Trainer where he oversaw training groups of 25 to 50 people. Bill has studied, trained and earned his certification from NFPT, National Federation of Professional, and NFPT Master Fitness Trainer, in 2007. Bill began personal training in 1989 and has trained, and/or, counseled more than 4,300 people towards improving their levels of fitness. He also played college baseball. Served in the United States Air Force and was accepted into the PGA Apprentice Program in 1997 to become a professional golfer.
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