By Steve Nugent, NMD, PhD
Water is the true elixir of life on planet Earth. But it is far more popular for water sports than for its natural purpose—hydrating your body to maintain life. I have often heard complaints in response to my counseling to drink more water. The most common are “I don’t like the taste of water” and “I can’t drink that much water.” As much as I like to be gentle in my counseling, I have to emphasize that water is essential, not only to life but also to the success of any nutritional program. So…get over it!
The fact is only water is water. That’s been proven by peer-reviewed scientific studies.
Before we proceeding any further, let’s look at a few basic facts about this wonderful, wet substance:
- Muscle is 74.8% water (on average). That’s why muscle is approximately three times heavier per inch than fat.
- A person’s total body weight is typically about 59% water weight.
- On average, a person’s fat weight is approximately 21.2% water weight.
- Blood (which is mostly water) makes up about 8% of the average person’s body weight.
What we have learned
Imagine that a food-deprived, water-deprived rat comes upon a tube full of liquid. At first it does not know what is in the tube. How will it know how much to drink? Until it tastes the liquid, it will not know. If the liquid is plain water, the rat will drink a certain amount based on how long it has been deprived of water. If the liquid is sugar water, the rat’s intake depends on its need for food, not its need for water. If the liquid contains saccharin, again the rat’s intake depends on its need for food. The rat treats the solution as food, even though it is not. Taste tells the rat whether to use its thirst system or hunger system. If the rat were also salt-deficient, salty-tasting liquid could trigger yet another mechanism. The similarities between rats and other mammals (including people) concerning hydration and satiety (satisfaction) are very alike. The only difference is that we humans add our likes and dislikes in terms of taste, while most other animals are very happy drinking water. Your satiety receptors will tell you if it is water or liquid food. If the brain detects water, it uses the liquid for what water was intended for—hydration of cells and tissue. If it detects liquid food, you will only derive a partial hydration benefit because only the mechanisms for food digestion are set in motion. This means ice tea, soda pop, coffee, etc. register as liquid food by the brain—not as water.
“How much do I have to drink?”
How much water should you drink? That’s a big question since we are all genetically and biochemically unique. However, we do have some good general guidelines:
Twenty-four hours per day you lose water. You lose water with every breath you exhale because there is moisture in it. You lose water all day through the pores of your skin even when you don’t know you are perspiring, and even if you are absolutely still. Of course, you also lose water when you urinate, and even solid waste contains water. The point is you must have water not only to live, but, if you become dehydrated, to feel well again. Headaches, fatigue, weakness, etc. may result from inadequate hydration. If you do nothing strenuous, you need at least 48 ounces of water daily to stay hydrated. The more you push your system, the more water you need. Also, the more excess body fat you have, the more water you must drink since fat lowers your hydration efficiency. People trying to lose weight should avoid scales since water is heavy and clouds your measurement of true fat loss. If you want to lose weight, a general rule is to drink half your body weight in ounces. Example:200 lbs. require 100 ounces of water daily (for tough weight-loss cases, not minimum hydration).
Remember: Only water is water, and water is essential to your health and wellbeing.
The Physiology of Exercise
You should also be aware of a little more science about the biochemistry and physiology of exercise. The various biochemical events that take place during all phases of exercise (beginning, during and following a workout) alter the physiology in ways that the body’s primary consideration becomes supplying adequate amounts of the most available source of fuel. At the start of a workout, whether anaerobic or aerobic, the body’s initial response is to provide the working muscles with sufficient energy to meet the demands of the workload.
Adenosine triphosphate (ATP) is the chemical substance within the body that supplies the energy that enables muscles to contract or relax. During muscular activity, ATP is converted to adenosine diphosphate, or ADP, while releasing direct energy for the muscle.
After the ATP and creatine phosphate anaerobic energy source is depleted, glucose is used by the body. After a few more seconds of exertion, stored muscle glycogen will be called upon to contribute energy by being broken down into glucose. So now all three systems are providing energy together. After the first 45-120 seconds of exertion, glycogen becomes the primary source of energy.
The first two minutes of activity should be primarily anaerobic, meaning the body does not use oxygen to metabolize stored glycogen. Usually any burst of activity that lasts less than a minute or two is considered predominantly anaerobic. One of the byproducts of anaerobic metabolism is lactic acid (lactate) that as it builds up, impairs performance and contributes to muscle soreness. Measuring lactic acid in the blood is one way of determining if anaerobic metabolism is being sed to provide energy. Between 120-140 seconds, glycogen becomes the primary source of energy, and the aerobic energy system starts kicking into action. After about four minutes, the energy supply is completely aerobic. using glycogen and fatty acids as energy. Aerobic means “with oxygen.” Oxygen is used to help metabolize (oxidize) stored fatty acids (triglycerides) to ATP through a complex process known as the Tricarboxylic Acid Cycle (Kreb’s Cycle or Citric Acid Cycle). The longer the duration of exertion, the higher the percentage of fats burned. With aerobic training, the body becomes more efficient at using fat as an energy source for strenuous work and recovery. Exercise enthusiasts call this “getting in shape.”