H20 – What’s the Magic Number?

Sixteen glasses a day. Eight cups a day. Forty percent of your body weight in ounces. Drink when you’re thirsty. Drink when you’re hungry. Drink when you’re sweating. Don’t drink coffee or soda. Don’t drink tap water. Don’t drink bottled water. Don’t drink carbonated water.

Does anyone else feel like there is no right way to drink the right amount and right kind of water? How much is enough? How much is too much? With summer quickly approaching (well, hopefully by the time you read this), hydration and dehydration will again be a hot topic (get it? Summer = hot? Sorry, I’ll stop). I had questions about my own water intake, so I did the hard work for you on what and when you should drink.

Our bodies are made up of about 60 percent water. This water is in our blood, muscles, connective tissue, organs and interstitial space (I’ll buy you a glass of something other than water if you can tell me what that is). Our bodies have also developed over time an amazing mechanism to tell our brains when we are thirsty and need to drink more water. However, with everyone’s busy lives, many of us have ignored that trigger too many times and become dehydrated, meaning our bodies do not contain enough water to function optimally.

When we are dehydrated, several things can happen. Mood and concentration can become impaired, headaches become more common and severe, physical performance can suffer, whether at the gym or on the jobsite, and endurance is reduced; meaning we cannot sustain physical or mental activities for extended periods of time. Dehydration happens when fluid intake is less than fluid output. This can happen during intense workouts, in hot weather, in dry climates, during illness, while breastfeeding or after drinking substantial amounts of alcohol. Concrete cutting professionals working in hot, dry weather need to be especially vigilant. Water loss of as little as one percent of your body weight can cause mild dehydration.

We’ve covered the negatives, so let’s focus on the positives! Water serves many vital functions and provides our bodies with a great deal of benefits. Besides keeping us alive, studies have shown the benefits of water include increased metabolism, weight loss, prevention of illness, maximizing physical performance, increased energy and brain function, headache prevention and the ever-popular hangover cure. These are covered in detail below:

Increased Metabolism

Some studies have shown that drinking 500mL (17 oz.) of water can temporarily (up to 90 minutes) boost metabolism by 24-30 percent and drinking 2 liters (68 oz.) in one day can increase energy expenditure by about 96 calories a day. So just by drinking enough water, theoretically you could lose an extra pound a month or 12 pounds a year! Cold water is best for this, because the body then has to burn calories to warm the cold water to body temperature.

Weight Loss

Drinking water 30 minutes before a meal has also been shown to reduce the number of calories consumed during a meal, because your stomach has less room for food. One study showed that dieters who drank 500mL (17 oz.) of water before meals lost 44 percent more weight over a period of 12 weeks compared to those who didn’t.

Prevention of Illness

Increased water intake has been shown in some studies to lower risk of developing bladder and colorectal cancer, kidney stones and constipation.

Maximizing Physical Performance

Athletes and those working in the construction field can lose up to 6-10 percent of their water weight via sweat during workouts or on the jobsite. This can lead to altered body temperature control, reduced motivation, increased fatigue and make physical activity feel more difficult, both physically and mentally. Optimal hydration can prevent this from happening and may even reduce the oxidative stress that occurs during intense physical activity.

Increased Energy and Brain Function

Even mild dehydration of 1-3 percent of body weight can impair many aspects of brain function. Studies have shown that in young men a fluid loss of 1.6 percent was detrimental to working memory and increased feelings of anxiety and fatigue. This is about 1.5-4.5 pounds on a 150-pound person. This fluid loss can easily occur through normal daily activities and is intensified during exercise or working in high heat.

Headache Prevention and Treatment

In some people, dehydration can trigger headaches and migraines. Water can relieve these headaches or make them less severe and shorter. So, your headache could be caused by not drinking enough water! No Advil needed.

Hangover Prevention 

Most of us have dealt with a hangover or twenty-six. Maybe those are behind you now, but if they are not, water is your new best friend. It’s no secret that many of the symptoms of hangovers, like thirst, fatigue, headache and dry mouth, are caused by dehydration. While dehydration is not the main cause of hangovers, it is one factor that is easily controlled. A good way to reduce hangovers is to alternate a glass of water with each alcoholic beverage you consume, and drink at least one really big glass of water before you go to bed.

Water, however, is not the only way to stay hydrated. One myth is that caffeinated drinks like coffee or tea don’t count towards staying hydrated because caffeine is a diuretic. While caffeine is indeed a diuretic, the effect of these beverages is very weak and fairly insignificant in causing your body to dehydrate (This does not apply to energy drinks like Monster, Rockstar, Red Bull, etc. These drinks contain a much higher amount of caffeine, along with additional stimulants. See the March 2013 issue of Concrete Openings for more info on “The Dangers of Energy Drinks”). Additionally, most foods are loaded with water, especially fruits, vegetables and even meat, fish and eggs. So, in normal conditions, your daily diet is likely providing you with enough water to stay hydrated. Of course, an extra glass or two is never a bad idea.

Another water alternative, and one that has been getting a lot of traction recently is carbonated water. Also known as sparkling water, club soda, seltzer water and fizzy water, this is water that has been infused with carbon dioxide gas under pressure. With the exception of seltzer water, they usually have salt added to improve the taste and sometimes other minerals are included. Natural sparkling mineral waters like Perrier and San Pellegrino are different because these waters are captured naturally from a mineral spring and tend to contain minerals and sulfur compounds. These waters are often carbonated as well. Tonic water is a form of carbonated water that contains a bitter compound called quinine, along with sugar or high-fructose corn syrup (we’ve discussed high-fructose corn syrup before – stay away)

Concerns about carbonated water in the past are that it is acidic and could wear away the enamel on your teeth and decrease bone density. Studies have shown those to be myths, but there are actually a few benefits of drinking carbonated water.

Some people are addicted to sugary sodas – but maybe it’s just the fizzy taste they like? Sugary beverages, whether carbonated or not, can destroy tooth enamel and reduce bone density. So, an alternative without the sugar is a better option. Carbonated water may also increase feelings of fullness, because the carbonation may help food to remain in the first part of your stomach longer, which triggers a sensation of being full and can reduce the number of calories you consume.

Author’s note – I recently invested in a Soda Stream and it’s one of the best purchases I’ve ever made. I save money on buying expensive carbonated water and I cut down on all those aluminum cans used. I recommend it to anyone who likes carbonation. (This note was in no way sponsored by Soda Stream – but call me guys, I’m happy to endorse).

So, how much water is best? There is no one size fits all recommendation. Everyone is different, and your climate, diet, activity level, age and what you drink are all factors. The solution is simple. When you are thirsty, drink. When not thirsty anymore, stop. During high heat and exercise, drink enough to compensate for the lost fluids. That’s really about it! Older adults and children should drink a little more. Listen to your body, and don’t ignore your thirst mechanism.


Erin O’Brien, MS, ATC is a Certified Athletic Trainer and Marketing Director for O’Brien International, the association management company that manages the Concrete Sawing & Drilling Association. O’Brien received her Bachelor of Science degree in Athletic Training from Ohio University and her Master of Science degree in Applied Physiology and Kinesiology from the University of Florida. She is also a Certified Level 2 CrossFit Instructor and member of CrossFit9 in St. Petersburg, FL. She is a regular contributor to Concrete Openings magazine. She can be reached at erin@csda.org or 727-577-5002.

Author: Matthew Meeks

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