Staying up late to revise for a test is often considered a normal part of school life, but research at the University of California, Los Angeles suggests that it could be doing more harm than good. The study, published in the journal Child Development, focused on the studying and bed rest habits of 535 students at the university and whether they experienced academic problems, such as performing worse than usual on tests or not understanding their lessons. The research found that those who spend less time sleeping to fit in extra study time actually led to worse performance in tests. "As other studies have found, our results indicated that extra time spent studying cuts into adolescents' sleep on a daily basis, and it is this reduced sleep that accounts for the increase in academic problems that occurs after days of increased studying," said Andrew J Fuligni, the study's senior author. "Although these nights of extra studying may seem necessary, they can come at a cost." Rather than sacrificing a proper night's sleep on your wooden bed, experts recommend studying in short bursts rather than long stretches. This is because the mind tends to wander the longer you spend focusing on a single subject.