PHOTO COMPOSITE BY DEAN SENSUI / DSENSUI@STARBULLETIN.COM
Drink Up!
Water intake takes on increased
importance during hot summer days,
especially for children and physically
active adults, physiologists advise
Do you wake up feeling like a slug summer mornings? Dehydration may be the culprit. Maintaining proper hydration levels is a crucial aspect of good health, but it often goes overlooked. We all know the eight-glasses-of-water-a-day rule, but how many actually put the words into practice?
Those eight glasses of water are needed because dehydration can cause people to feel incoherent, irritable and mentally sluggish, according to health experts. A more long-term effect of low water consumption is development of kidney stones and digestive problems, which are more prevalent among those who live in warmer climates.
We lose about a quart of water every day just by breathing, said John Claybaugh, chief of the physiology section at Tripler Army Medical Center. Additional water is lost through perspiration, tears, urine and stools.
Normally, body fluid is replaced throughout the day from the water and salt content of what we eat and drink. But the summer months make it more difficult to maintain a balance because of the higher temperatures and humidity, causing us to perspire more.
As the core body temperature rises, the body attempts to cool itself through perspiration.
The simplest way to check for dehydration is to check urine color, according to Beth Young, president of Hawaii Athletic Trainer's Association. It should be clear or pale yellow in color. If it begins to darken in color, fluid intake should increase. Other symptoms include dry mouth, thirst, headache, profuse sweating, stiff joints, fatigue and the inability to regulate body temperature. "The main thing is prevention," said Young.
Athletes can check their body weight before and after a workout. "We train athletes to monitor their own bodies," she said. "They need to drink two glasses of water for every pound they lose."
"People get into trouble when they push themselves beyond their limits," said Claybaugh. You see it happen in football games when they need to pull someone off to the sidelines, he said.
Football players are especially prone to dehydration because of all the heavy equipment they wear, added Young.
It's best to drink small amounts of fluid throughout the day. If you consume large amounts of water at once, it will not be absorbed into the body. The kidneys immediately flush out the liquid, sending you to the restroom, said Young.
Claybaugh suggested, "Drink water only when thirsty. You are only slightly dehydrated when you are thirsty," he said. Caffeinated drinks also act as a diuretic, he added. That means the products increase urine output, which raises the amount of fluid loss. Alcohol also increases urine output, further increasing fluid loss.
WHEN DEHYDRATION is not addressed, it can lead to more serious conditions like heatstroke.
"If you are dizzy or out of breath, go to a shady place," said Young. Work out in cooler temperatures, and if possible, wait until the sun goes down. Listening to the weather report is helpful, and people not used to working out in hot temperatures need to be even more careful, she said. "Obese people need to exercise at a slower, moderate rate for longer periods of time."
Individuals should also try to keep heads covered while in the sun so they do not absorb heat, said Young. Dark-haired individuals will soak up more heat, she added.
Another concern is high altitudes, said Claybaugh. Thirst is suppressed at high altitudes, so hikers or mountain climbers may not feel thirsty even if they are dehydrated.
People also need to drink more water as they get older. "The capacity goes down ... it is a natural part of aging," said Young. "You are born with 75 percent water ... you die with 60 percent water. That is why babies have such nice skin when they are born."
DEHYDRATION IS especially dangerous for children. Parents may be unaware of the extra need for water now that more children are involved in athletics, some playing two or three soccer games a day during tournaments, Young said. Children should stay out of the sun when they are not playing, and they should consume a couple of glasses of water a half-hour prior to activity.
"That rule pertains to any physically active person," said Young. "The coach may not give regular water breaks, so kids need to be made aware of their needs."
"A child can be dehydrated and look perfectly fine," said Dr. James Nakamura, a pediatrician. Kids who are not involved in sports or rigorous activity still require a minimum of six to eight cups of fluid a day. Children who are more physically active need to add about four more glasses of water for every hour of activity.
One thing people do not need to worry about in maintaining the body's salt and water is salt intake, Nakamura added. "Everyone has way too much salt in their diet."
Potlucks after games really help the kids, he added. Carbohydrates help nourish the muscles and hold onto water molecules. Water is not the only thing that parents need to worry about. Proper nutrition is important, Nakamura said.
Sports drinks are not a necessity, but an elaborate marketing ploy, he added. Milk and water are all children really need. If a child appears tired or is performing poorly, their fluid intake may need to be evaluated.
"Kids are so used to drinking juice and other sugary drinks. They don't like water because it has no taste," Nakamura said. "It's much healthier and cheaper to just drink ice water."
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Tips for all
Too much of a good thing
While maintaining proper hydration levels is important, it's important not to go overboard. Overhydration is deadly, said John Claybaugh, chief of the physiology section at Tripler Army Medical Center."Do not drink beyond your thirst," he warned. "It can be very dangerous when you start messing around with Mother Nature." Most people could drink up to a gallon of water a day and not be harmed, he said.
People who overhydrate with water while exercising are prone to a life-threatening condition called hyponatremia, when the body's salt concentration drops. Antidiuretic hormone levels increase when exercising, so the kidneys cannot remove the excess water.
"An electrolyte-fortified drink is safer than water if you feel you should have more fluid than the amount to quench your thirst," he said. That way, the concentration of body fluids does not change radically.
A whole lot of sweat
Honolulu was named the 23rd-sweatiest city in Old Spice's second annual "Sweatiest City Study," based on sales of the most foot-odor prevention products in the nation.In the No. 1 spot is Phoenix, Ariz., which climbed eight spots from last year to claim the title as the nation's top perspiration producer.
The average resident lost nearly 0.9 liters per hour (equivalent to 2 1/2 cans of 12-ounce soft drinks) during a typical summer day.
Houston ranked No. 2 and Miami was third. The least sweaty cities included Spokane, Seattle and San Francisco.
How to beat the summer heat
>> Drink at least eight to 10 glasses of water a day. Young children need at least six to eight glasses a day.>> Wear lightweight clothing such as cotton. Avoid dark colors and materials like polyester and nylon that encourage perspiration.
>> Replace salt and minerals when participating in strenuous activities. Sweating removes the body's salt and minerals. Sports drinks like Gatorade can replace lost minerals.
>> Make sure kids are well rested and receiving proper nutrition.
>> Wear a hat and use sunscreen.
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