Too much water is bad way to beat heat

Overhydration can kill, health officials warn By Christina E. Sanchez • THE TENNESSEAN • July 4, 2010 You're sweating profusely from the sizzling heat, and you're so thirsty you could chug a gallon of water. But how much should you drink? The answer isn't so simple: not too much and not too little. Either way can harm you. Not enough and you can get dehydrated, and too much can cause hypernatremia, or water intoxication. Health officials are warning that with the impending return of scorching, relentless temperatures in the 90s, people should be smart about when they're outside, what they wear and how much they drink. More than 1,000 people were treated and three died in Tennessee in 2008 for heat-related illness, according to the Tennessee Department of Health. Nationwide, about 700 people die each year. "Heat poses a risk to all of us under different situations," said Susan Cooper, state health commissioner. "Young children and infants and people age 65 and older with chronic conditions are at higher risk. We really just need to be attentive to our own personal needs and use good judgment." The tough part about treating heat-related illnesses is knowing the source of the problem. But symptoms can be similar across the different types. Common signs include dizziness, confusion, nausea, irritability, a rapid heartbeat and a headache. Often, the least-discussed illness connected with extreme heat is water intoxication. It occurs when a person drinks too much fluid, causing the brain to swell, said Mari-Etta Parrish, a registered dietitian and board-certified sports nutritionist at Baptist Sports Medicine. "Drinking too much water is far more dangerous than not drinking enough," Parrish said. "Your body will stop you when you are dehydrated, but when you overdrink, that's not always the case." Contest turns deadly A high-profile case in California highlighted the danger of water intoxication. A 28-year-old woman died in 2007 after taking part in a radio contest in which she had to drink as much water as possible without urinating to win a video game system. She was found dead a few hours after the contest. Water intoxication can happen to anyone, but it is most common in marathon runners who sweat a lot and try to compensate with water. Along with water they also need sodium, a lack of which can increase the risk of hypernatremia. Parrish said the maximum fluid intake is 32 ounces an hour, and that should be balanced with getting enough sodium to keep the body's chemistry in check. It can take six hours for the body to adjust to too much water. A 2005 study in The New England Journal of Medicine found that 13 percent of Boston Marathoners had hypernatremia, which can vary in severity. The most common way to tell is by comparing pre-race weight to post-race weight. If someone weighs more after the long run, it could mean too much water. Cooper said infants can be at risk for water intoxication because they don't need plain water. "Healthy babies' water needs are met by correct amounts of breast milk or properly prepared formula," Cooper said. "The best prevention for heat-related illness in a child is to limit exposure." Children at risk Dehydration, when the body does not have enough fluid, is a more common result of heat exposure. It can lead to heat stroke, a condition in which the body can't control its own temperature. Dr. Andrew Gregory, who practices pediatric sports medicine, sees dehydration and heat stroke in a lot of young football players. Last year, four football players died in the United States, including one in Tennessee. "Your body can get used to exercising and working in the heat, but it takes about two weeks," Gregory said. "You should also practice at cooler times of the day." Checking a child's temperature can be a good indicator of heat stroke. When in doubt, Gregory said, call 911. "It's important that you recognize and treat problems quickly," he said.