Fluid intake is possibly the most important discussion a trainer will have with a client. Studies have indicated that in addition to maintaining normal body functions, proper hydration eliminates the most preventable risk factor for coronary artery disease: dehydration. Water lubricates your joints, keeps your blood and digestive tract flowing, mobilizes fat to burn more easily, and moistens all of your mucous membranes. Hydrating properly is the first (and probably easiest) step you can take towards great health.
Put simply, dehydration means that your body has lost more fluids than it’s taken in. When we sweat, breathe, pass waste or get sick (with either vomiting or diarrhea), we lose water. Ideally, we would put back exactly what we lose. As simple as that concept sounds, the amount of fluid each of us should drink causes quite a lot of confusion. Most of us grew up learning that we should drink at least 64 oz. of water per day. Recent studies have debunked that myth. The new, reasonable indicator for fluid needs is based on the color of our urine. The urine of a properly hydrated individual will be light lemon-yellow or clear. Dark yellow or amber urine is symptomatic of dehydration.
What’s Your Risk?
The risk factors for dehydration vary between individuals. Young children and older adults may have underdeveloped or impaired thirst receptors or may forget to drink, and their ability to conserve water is reduced. They may not know when they’re thirsty, or they may forget to act upon the impulse. Additionally, those suffering from chronic illness like diabetes, kidney disease, alcoholism, and adrenal gland disorders are particularly susceptible. While teenagers may feel thirsty when engaged in an activity, their inexperience hydrating properly leaves them vulnerable. Endurance athletes and those engaged in strenuous activities in hot, humid or high-altitude conditions are especially at risk. While hot conditions cause sweating (which cools you down), humidity prevents the sweat from evaporating, which means that it can’t cool you as quickly, resulting in increased body temperature. Additionally, endurance athletes find themselves particularly challenged because the longer they exercise, the more difficult maintaining proper fluid levels becomes. Finally, in all of these groups, dehydration is cumulative over several days. Moderate dehydration over several days combined with activity may result in the uncomfortable and dangerous symptoms of more serious dehydration.
What are the Symptoms?
Symptoms of dehydration range from mild to serious.
Mild to moderate dehydration can cause:
· Sleepiness or tiredness – children are likely to be less active than usual
· Decreased urine output – no wet diapers for three hours for infants and eight hours or more without urination of older children and teens.
· Few or no tears when crying
· Dry skin
· Headache constipation dizziness or lightheadedness
· Dry, sticky mouth
Severe dehydration, a medical emergency, can cause
· Extreme thirst
· Extreme fussiness or sleepiness in infants and children, irritability and confusion in adults
· Very dry mouth, skin, and mucous membranes
· Lack of sweating
· Little or no urination – any urine that is produced will be dark yellow or amber
· Sunken eyes
· Shriveled and dry skin that lacks elasticity and doesn’t “bounce back” when pinched into a fold
· In infants, sunken fontanels – the soft spots on the tip of a baby’s head
· Low blood pressure
· Rapid heartbeat
· Rapid breathing
· No tears when crying
· In the most serious conditions, delirium, unconsciousness, hyperthermia, and death
Is Water Always Best?
Water is life. Water is the reason we’re here. Water is great. But water is not always best. When you sweat, you are not losing pure water. You are losing a solution of water, sodium chloride and other chemicals. You must replace what is lost, thus, a combination of water plus sodium is best. But honestly, who wants to drink salt water? Yuck!
Consider the sports drink (Gatorade, Powerade, etc.), which is a combination of water, sodium, carbohydrates, and other additives. Studies have shown that athletes who hydrate with a combination of water and sports drink remain hydrated longer. The nutritionist of the defunct Phonak cycling team fed his riders one bottle of Gatorade for every four bottles of water. He maintained that this combination optimized hydration and eliminated stomach cramps. Recent studies have indicated that sports drinks with added protein may keep athletes hydrated longer than traditional sports drinks.
Water consumption throughout the day is essential to maintain normal body functions. While exercising, however, sports drinks keep you hydrated longer and more efficiently than pure water. Additionally, carbohydrates in sports drinks increase your endurance and aid in recovery.
How Much Is Too Much?
Too much water results in bloating and discomfort, and can be fatal. Keep your urine light yellow or clear.
If You Like Numbers and Formulas…
Here you go. This chart and formula, adapted from Fitness: The Complete Guide, offers a ballpark figure for your water requirements based on your weight and activity level.
0.5 – Sedentary, no sports or training
0.6 – Jogger or light fitness training
0.7 – Sports participation or moderate training three times per week
0.8 – Moderate daily weight training or aerobic training
0.9 – Heavy weight training daily
1.0 – Heavy weight training daily plus sports training, or “2 a-day” training
Now, multiply your weight by your need factor. You can divide that by 8 to determine the volume of water you should drink 8 times per day.
Example: 140 lbs. x 0.8 = 112 oz. of water per day
112 oz. per day/8 = 14 oz.
Thus, a 140 pound person who engages in moderate weight or aerobic training daily should drink 8-14 oz. glasses of water per day.
Remember, though, when working out, sports drinks (especially with added protein) increase endurance and aid in recovery.
Good luck, stay fit, and drink your water.
Hatfield, Fredrick C. Fitness: The Complete Guide, 8th ed. Carpinteria: International Sports Sciences Association, 2010.
Mayo Clinic Staff, “Dehydration.” Answers.
Remick, D., et al. “Hyperthermia and Dehydration-Related Deaths Associated with Intentional Rapid Weight Loss in three Collegiate Wrestlers – North Carolina, Wisconsin, and Michigan, November-December 1997.” Journal of the American Medical Association. 1998
Fitzgerald, Matt. “Which Fluid Hydrates Best: Water or a Sports Drink?” Active.com.