New research suggests that more than half of children in the United States found that more teens should really stay hydrated, and the drink of choice should ideally be water.

The study that was published in the American Journal of Public Health found that 54.5 percent of children ages 6 to 19 are not properly hydrated, at least by the standards set forth by the study. The findings were based on one-time urine samples taken from more than 4,000 children. However, researchers stressed that just because they could use more to drink, doesn't mean most children are seriously dehydrated.

"We are not saying kids are dropping like flies," says Erica Kenney, a researcher at Harvard University. "What we are saying is that they are not as hydrated as they should be for proper health and probably for proper school performance."

She and her colleagues continued by saying that even mild dehydration can be associated with "headache, irritability, poorer physical performance and reduced cognitive functioning."

For the study, researchers looked at how concentrated the urine of each child was by comparing how much was water versus how much other wastes from the body were present. To judge the concentration of your own urine, examine the color. A light yellow is less concentrated containing more water while a dark yellow is more concentrated containing less water and is often linked with dehydration.

For the study, researchers considered children inadequately hydrated if the concentration reached established levels of other studies that were linked to sluggish thinking and changes in a child's mood. Researchers also found that boys and African-American children were more likely than girls and children of other races to have highly concentrated urine.

They also took a closer look at what the children drank. They found that water and other sugary beverages were the most common and that larger quantities of both were associated with less concentrated urine. However, extra water was most strongly linked with staying in what the researchers considered a healthy zone for hydration.

"We would not at all recommend that kids drink more sugary drinks," said Kenny, who noted that water is most definitely the healthier choice.

Some kids may not get enough water because they dislike the taste or don't like the look of the "old, outdated" water fountains in their schools. Several public health campaigns are currently urging people to drink more water.

However, not all the experts agree on these latest public health campaigns. Stanley Goldfarb, a professor of medicine at the University of Pennsylvania, said the new study did not use the best measure of dehydration, which requires 24-hour urine collection. And he says that "this idea that you are going to drink water and then think better, when you are not dehydrated to begin with, has not been proven."