American children are not drinking enough water, and more than half of children and teenagers are dehydrated, a new study concluded. Fully 25 percent of kids in the scientific study said they drank no plain water at all on an average day.

More than 4,000 medical records of boys and girls between the ages of six and 19 were examined. The data was obtained from the National Health and Nutrition Examination Survey, conducted annually by the Centers for Disease Control and Prevention. Urine osmolality, a measure of the concentration of components in urine, was used to determine whether subjects were dehydrated.

Boys were 76 percent more likely than girls to be dehydrated, the study reported. Non-Hispanic black respondents were 34 percent more likely than non-Hispanic whites to be dehydrated.

"These findings are significant because they highlight a potential health issue that has not been given a whole lot of attention in the past. Even though for most of these kids this is not an immediate, dramatic health threat, this is an issue that could really be reducing quality of life and well-being for many, many children and youth," Erica Kenney from the Department of Social and Behavioral Sciences at Harvard Chan School said.

Water is essential for a wide range of metabolic processes, and is especially important for children, with their active lifestyles, researchers point out. Mild dehydration can result in upset stomachs, irritability, poor physical performance and reduced cognitive abilities. Severe cases can cause serious health problems, and can even be fatal.

"The good news is that this is a public health problem with a simple solution. If we can focus on helping children drink more water - a low-cost, no-calorie beverage - we can improve their hydration status, which may allow many children to feel better throughout the day and do better in school," said Steven Gortmaker, senior author on the study.

Researchers believe that by encouraging children to drink more water, the youngsters can do better physically, as well as mentally. Proper hydration will also help encourage better health throughout life, researchers point out. In addition to hydrating the body, water has no calories and sugar, and is typically free or inexpensive. This could make water an attractive option for teens looking to reduce their intake of calories, or who are looking to replace soda in their diet for other reasons.

Analysis of the water drinking habits of children across the United States was published in the American Journal of Public Health.

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