Have a glass of water (or a cherry coke)

Feeling thirsty?

You should probably avoid making decisions and complex mental tasks.

We know that dehydration affects physical performance but a new study from the Georgia Institute of Technology shows how it diminishes mental acuity as well.

"We find that when people are mildly dehydrated they really don't do as well on tasks that require complex processing or on tasks that require a lot of their attention," said author Mindy Millard-Stafford.

The test involved a women playing a card game that required focus.

"When the women were dehydrated they had about 12 percent more total errors" in the game, said Stachenfeld.

She repeated the tests after the women drank sufficient water, and their performance improved. "We were able to improve executive function back to normal - in other words-- back to the baseline day - when they rehydrated," the scientist said.