And while many think they need nine hours, the optimum amount of sleep for a typical 16-year-old is just seven a night, according to scientists at Brigham Young University, in Utah.
Eric Eide, study author, said: 'We're not talking about sleep deprivation. The data simply says that seven hours is optimal at that age.' Reporting the findings in the Eastern Economics Journal, the team said the right amount of sleep decreases with age. The optimum amount of sleep for a ten-year-old is around nine hours while for 12-year-olds it is eight hours.
The researchers studied 1,724 primary and secondary school students across the U.S., assessing how much sleep they got and how they scored in standardised tests. The impact of sleep on test scores depended on a number of factors, such as how educated the child's parents were.
Economics professor Mark Showalter, who co-wrote the study, added: 'Most of our students at BYU, especially those that took early-morning seminary classes in high school, are going to realise that nine hours of sleep isn't what the top students do.'
Harming school performance: Tests showed that 16-year-olds did best in exams when they slept for seven hours - two hours less than is recommended.
Testing best: Pupils also do better in exams if they have a regular sleeping pattern
