- The Washington Times - Sunday, April 30, 2000

The most important thing we can put in our body every day is cheap, plentiful and portable.

It is water. Humans crave it, need it and are largely made up of it.

"The average human body is 60 percent water," says Dr. Aviad Haramati, professor of physiology at Georgetown University School of Medicine.

That means most of us, depending on age, are walking around with about 10 gallons sloshing around in different parts of our bodies. About six or seven gallons are inside the cells, another two gallons surround the cells, and about one gallon flows through the bloodstream, Dr. Haramati says.

Water helps our kidneys, heart, lungs and other internal organs work properly. It plumps up skin cells and helps them regenerate. It keeps the body from becoming exhausted.

Yet as quickly as humans put water in, it goes back out through urination, perspiration and use by the lungs, which need moisture to work.

"On any given day, adults lose 2.5 quarts," Dr. Haramati says. "The average person gets about a quart from fruits and vegetables and makes about another 12 ounces metabolically. So you have to drink 1.2 quarts just to make up for the loss on that day.

"As soon as you start exercising, your water requirements shoot up immediately," he says. "In hot weather, you lose another liter or two. If you are exercising vigorously, you can lose up to six liters of water."

Dr. Haramati and other experts say most Americans do not meet the American Dietetic Association's recommendation of six to eight 8-ounce glasses of water daily.

"Most of us walk around in a state of

dehydration," says Jackie Berning, a Colorado dietitian who is a spokeswoman for the American Dietetic Association. "Whether you are a professional athlete or the average guy at the office, that is going to show in fatigue and a lack of coordination. I try to get all the people I work with, whether a recreational athlete or a professional athlete, to maintain hydration throughout the day, then top off with at least 16 ounces of water at least two hours before a workout."

Ellie Zografakis, a dietitian, personal trainer and a spokeswoman for the American Council on Exercise, says a person also should drink about 16 ounces after exercise.

"You can't do as much during your workout if you are dehydrated," she says. "It has been documented by the American College of Sports Medicine that if you are dehydrated, you tend to work out 10 to 15 minutes less and are fatigued more easily."

Ms. Zografakis warns her clients not to wait until they are thirsty to take a drink. By the time the body is signaling the brain's thirst center, the body is already craving fluids.

The easiest way to know if your body has the proper fluid balance is to take a look at your urine, Dr. Haramati advises. If it is clear, you have been drinking enough. If it is dark and concentrated, you are somewhat dehydrated and should drink more, he says.

Signs of more serious dehydration include dry mouth, flushed skin and headache. In severe, deadly dehydration (which can occur after many days with no fluids), body tissues and cells including brain cells begin to shrivel and die.

"To think of what happens when we lose water, think about a glass of tea with sugar added to it," Dr. Hamarati says. "If you left it there all day, it would become more concentrated. If we lack body fluid, we become more concentrated. The body has to pull water out of the cells. The cells shrink and don't work as well. That includes cells in the brain, heart and lungs."

It is easy to avoid becoming even slightly dehydrated if you constantly refill your glass as long as the glass is full of water and not soda or juice or coffee, he says.

"Water is the best beverage we can drink," Dr. Haramati says. Other fluids that can be counted toward the daily water requirement are decaffeinated coffee and tea. Milk and fruit juices have vitamin benefits but also contain more calories. Full-strength coffee and tea, caffeine-containing soda and alcoholic beverages actually work against you because they act as diuretics, causing you to lose fluids, Ms. Berning says.

Drinking enough water is particularly important for the very young and the very old, experts say.

The thirst reflex does not work optimally in the elderly, Dr. Haramati says, making dehydration one of the most frequent causes of hospitalization among people older than 65. Along with a reduced sense of thirst, aging also is associated with reduced kidney function, lower amounts of body water and a reduced fitness level, all of which can contribute to dehydration, Dr. Haramati says.

Infants and children have their own hydration needs, too.

Babies who are breast- or formula-fed and not yet on solid foods generally do not need additional water, Ms. Berning says. However, if the weather is very hot and the baby is sweating, he or she may benefit from an ounce or two of water given after a normal feeding.

If an infant has diarrhea or is vomiting, it is especially important to replace fluids. Signs of dehydration in babies include dry eyes, such as a lack of tears when crying, and a sunken "soft spot" on the scalp, Dr. Haramati says.

In children, signs of dehydration include complaints of a headache and a hot, flushed look (rather than a sweaty appearance) in hot weather, Ms. Berning says.

"In kids, the body surface area is less," she says. "They dissipate heat less than adults."

They also generally like to drink water less than adults. Generally, a child needs about half of an adult's daily fluid total.

"This is the Pepsi generation," Ms. Berning says. "Children would rather drink anything else but water."

Still, it is particularly important to urge children to drink, especially on a hot day, she says. Milk and juices are all right, but they add sugar and carbohydrates, she says. Sports drinks which also add sugar, salt and carbohydrates are a good option to get children to rehydrate because youngsters might like the taste, she says.

"If you drink just water, it dilutes plasma sodium, and you don't feel like you need to drink as much," she says. "If you drink sports drinks, especially in the summer, it maintains your electrolyte balance and maintains your drive to drink."

However, Dr. Hamarati is skeptical.

"Assuming a balanced diet, we have an excess of electrolytes," he says. "If you are a competitive athlete or trekking through the desert, then you might need more electrolytes. However, most of us just need water, nothing else."

Infants and children also benefit from the fluoride that is added to water in many areas. The presence of cavities has gone down 40 to 60 percent for those who have consumed fluoridated water from birth through adolescence, according to the American Dietetic Association.

The Centers for Disease Control and Prevention estimates that about 62 percent of the American population has access to fluoridated water.

The ADA advises against giving fluoride supplements to children and infants who live in fluoridated areas. Too much fluoride can result in fluorosis, which is mottled or stained teeth. Most children are getting more fluoride than parents think because products such as infant formula, cereal and some bottled waters also contain the substance.

LOAD COMMENTS ()

 

Click to Read More

Click to Hide