In today's health matters, lack of sleep takes a toll on your child's grades.

Spanish researchers looked at the sleep habits and academic performance of more than a hundred six and seven year olds.

They found students who slept eight hours a night performed more poorly in school than those who slept nine to eleven hours a night.

Not enough shut-eye also negatively effected memory, learning and motivation in the kids... Though it was to a lesser extent.

Study authors concluded primary school students should get at least nine hours of sleep a night to ensure they perform at their best in school.