Drinking water may boost brain power: study

Results showed that subjects who drank about three cups of water (24 ounces/775 milliliters) before taking a battery of cognitive tests performed better on a test measuring reaction time than subjects who didn't drink water. This difference was especially noticeable when the subjects were especially thirsty, with researchers speculating that being thirsty may take attention away from the task at hand, slowing response time.

Still, in one test, on rule-learning, thirsty subjects actually fared better, but researchers aren't clear why. "It might be that physiological processes [of drinking or not drinking water] affect performance on different tasks in different ways," study researcher Caroline Edmonds, of the University of East London School of Psychology in England, told LiveScience. She added that thirst might lead to better performance on some tasks, because the hormone vasopressin, which activates the thirst response, has been linked to attention and arousal.

In the study, 34 adult subjects were asked to abstain from food and drink starting at 9pm before coming into the lab for testing the next morning. In some cases, subjects were offered a cereal bar with water for breakfast. On another day, they were offered a cereal bar with no water.

Prior research has found that water consumption can improve memory in children, LiveScience reports.

The new study was published online July 16 in the journal Frontiers in Human Neuroscience.