(CNN) -- There's one simple liquid that has a huge effect on how well your family feels today: water.
More than half of children and teenagers in the United States might not be properly hydrated, according to a nationwide study from the Harvard T. H. Chan School of Public Health. In fact, 54.5% of the students in the study had urine concentrations that qualified them as below their minimum daily water intake.
"I was surprised that almost one in four kids drank no water during the course of their day," said lead author Erica Kenney, a postdoctoral research fellow in the Department of Social and Behavioral Sciences at Harvard Chan School.
Not all children and adolescents were equally dehydrated, according to the study. Boys surveyed were 76% more likely to be inadequately hydrated than girls, which was a statistically significant finding.
While mild dehydration typically isn't life threatening, not drinking enough water could result in cognitive impairment, headaches and even nausea in severe cases, according to Dr. Anisha Patel, a pediatrician at the University of California, San Francisco.
For younger children, symptoms include fussiness, infrequent urination, dry mouth and a lack of tears when the child is crying. "Keeping kids hydrated can help them with learning and to perform better in school," said Patel.
But how much water is enough? For kids and teenagers, daily water requirements vary quite a bit and depend on several factors, including age and activity level.
For total water intake, experts recommend that kids get the majority from drinking water, but also a small amount from food. Kids 1 to 3 years old need roughly four cups of drinking water daily. For kids 4 to 8, five cups is recommended a day. Once kids reach 9, the requirements differ by sex. For boys 9 to 13, eight cups of water is recommended daily, while girls need about seven cups.
"Children don't have a highly developed thirst mechanism, so they're especially vulnerable to becoming dehydrated," said Dianne Ward, a professor of nutrition in the UNC Chapel Hill Gillings School of Global Public Health and director of the Intervention and Policy Division. "So parents need to remind their children to drink water," Ward says.
When you think about losing water from the body, urination typically comes to mind. But breathing, sweating and your skin are all other paths that water can take to exit the body. In fact, adults lose nearly 4 cups of water a day through the skin and normal breathing. That's why it's important to regularly rehydrate our bodies, which are roughly 60% water by mass depending on age and body composition.
All experts agreed that kids should steer clear of caffeinated and sugary beverages because these drinks contain other ingredients that don't necessarily provide nutritional benefits. Even worse, beverages with caffeine are mildly diuretic, meaning they cause the body to produce more urine. This means that caffeine could even make dehydration worse.
While 99% of the U.S population has access to clean drinking water, some schools built before the 1980s may have contaminated drinking water because of lead water pipes, according to Patel. For these communities, purified water from outside sources or bottled water are possible alternatives.
The experts we spoke to all had one resounding message: schools need to do a better job of providing kids access to clean drinking water, and not just during lunch time.
Patel's research has shown that some schools have already taken steps in the right direction by providing water in attractive pitchers, refillable water bottles and easy-to-use fill stations.
At home, parents can start by setting by a good example: drinking primarily plain water to create a "culture of hydration," said Ward. "Children shouldn't even have to ask for water," and younger children in child care should have clean drinking water available to them at all times.
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