Pupils need nine hours' sleep

London: Children who get less than nine hours sleep a night struggle at school, research has shown.

The study assessed 142 primary pupils and compared the number of hours sleep with performance in a range of academic skills.

Most six and seven-year-olds deprived of sleep were less able to communicate and work out basic maths questions, researchers found. Their spelling, grammar and comprehension also suffered. Their memory and ability to learn were less affected. The study comes as more and more youngsters are allowed computers and televisions in their bedrooms.

Ramon Cladellas, of the Autonomous University of Barcelona which conducted the study, stressed the importance of a good night's sleep. He said: "Most children sleep less than is recommended for their intellectual development, which is hindered because the lack of sleep cannot be recovered."

Professor Russell Foster, head of neuroscience at Oxford University, said: "It is very clear that nine to nine-and-a-half hours is optimum for cognitive performance in pre-teens."

Adults need between six-and-a-half and eight-and-a-half hours' sleep, he said.