Teenagers who go to bed early and sleep longer have sharper brains, study finds

Researchers surprised at impact that even small differences in sleep make to adolescents' cognitive abilities

Teenagers who go to bed earlier and sleep for longer than their peers tend to have sharper mental skills and score better on cognitive tests, researchers have said.

A study of more than 3,000 adolescents showed that those who turned in earliest, slept the longest, and had the lowest sleeping heart rates outperformed others on reading, vocabulary, problem solving and other mental tests.