Drink Up! But How Much?

Water covers about seventy five percent of the planet, and composes seventy to ninety five percent of the cells of most living organisms.

Even considering this comparison between the human body and planet Earth, water is an immensely important component of health. Water is a transport medium in the body, it's used in evaporative cooling (sweating), it's a medium for chemical reactions, and accounts for about half of blood plasma. You might have heard that we can live without food for weeks, but without water we will likely perish in days even in otherwise optimal circumstances.

There exists the implication that proper hydration levels are imperative not only for general health, but also for physically active people. I grew up hearing that I should drink sixty four ounces of water daily for good health. Today, I would concede that is not a bad recommendation, but I will go on to claim this is not optimal hydration. The reason why is because everybody is different and their individual demands for water are different, too.

Let's consider two extremes--a professional adult athlete and a newborn baby. The baby, assuming it is healthy, has been growing and will likely continue to grow for the next fifteen to twenty years. The athlete is fully grown and is expending large amounts of energy by being physically active on a frequent basis. These two specimens could differ in body weight by as much as two hundred pounds, so their water intake should be equal, right? I'll break it down on a very basic level. If the athlete only needs sixty four ounces of water, and his/her body has enough mass to properly distribute the water, then how can a baby manage the same amount of water? If we consider a role reversal in which the baby can and does require sixty four ounces of water daily, then how is that anywhere near enough water for an adult who is highly active, sweating, and breathing heavily nearly everyday? No. It's too much water for the baby, and not enough for the athlete, respectively. The demands between the two subjects differ based on age, body weight, and level of physical activity if all else is equal.

    Have you ever noticed water pitchers and drinking glasses in court rooms, lecture halls, and in conference rooms? If you have never considered why this is, or if you've never participated in the events in these spaces, then know it's because consistent air passage along the trachea and oral cavity causes dehydration. People who are talking for extended periods of time tend to get a dry mouth, and gracious hosts of these events have offered the concession of a water supply. You might have noticed this phenomenon as you walk on a treadmill for a while; the intensity of the exertion may not be high (i.e., your not sweating that much), but your increased respiration has evaporated water from the inside of your body. This is also why carpet cleaners direct high-powered fans across or under the carpet because applying a wind source tends to evaporate moisture.

What if someone isn't physically active but is in a hot environment, such as sitting on the beach/pool all day without talking? Is that sixty four ounces of water enough? Probably not, no, since most beaches tend to correlate with high ambient temperatures, meaning this person is going to lose water via perspiration. Thirst is an indication that your hydration levels are low, and if you are thirsty, then you are already dehydrated.

Dehydration doesn't necessarily mean "emergency," but you are below the level of what the body needs. Don't wait until you are thirsty to drink water.

    In order to determine how much water we need we must consider each subject on its own without applying a global template. The biggest factors to keep in mind are body weight, physical activity level, level of respiration/talking, and exposure to high temperatures.

Written by Personal Trainer/Instructor; Justin Lee

Written by Personal Trainer/Instructor; Justin Lee

I calculate my baseline water intake level by starting with my body weight. I take this number which is measured in pounds, and I replace the unit of pounds with ounces.

Note I'm not converting the pounds into the equivalent number of ounces, but I'm simply replacing the pound unit with the ounce unit. I then take this number and multiply it by 0.6; this results in sixty percent of the first number. This is the baseline amount if water in ounces I should drink everyday. I say "baseline" because I live in a humid area, I speak somewhat frequently, and I'm physically active, therefore the calculated number is not sufficient for optimal hydration levels. For example, if a man weighs two hundred pounds, then he would multiply 200 by 0.6 and get the baseline result of 120 ounces of daily water. What works best for me is to get about 25% of it every morning soon after I wake up. I likeknowing that I've got a big chunk of my baseline water in my body as soon as possible in my day.

Now it's your turn! Weigh yourself, find your baseline water amount, and start hydrating!

- JL Fit