No lie-in! Teens need just seven hours sleep a night, study finds
They often protest that they need the extra hours in bed.
But getting too much sleep could in fact be leaving teenagers behind at school, according to research.
A study found that they performed better academically if they cut down on lie-ins and had more regular sleep patterns.
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
HOW MUCH SLEEP IS OK
Most studies suggest teenagers need at least nine hours sleep. And previous studies suggest that children between age seven and 12 need 11 hours in bed.
But, according to this latest research by Brigham Young University, the right amount – in terms of testing best in exams – is as follows:
Aged 10: nine to 9.5 hours
Aged 12: Eight to 8.5 hours
Aged 16: Seven hours
Nevertheless, sleep studies have recorded a variety of results with differing optimal amounts, so you may want to see for yourself which suits your child or teenager best.
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
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.'
Testing best: Pupils also do better in exams if they have a regular sleeping pattern
According to researchers at the University of Chicago, those who sleep for less than five hours a night for periods of longer than a week have significantly lower levels of testosterone than those who get a full night's rest.
And with testosterone affecting men's libido and energy levels, those who miss out on sleep are much more likely to be put off sex.
The affect is so drastic it reduces the hormone to levels more akin to someone 15 years older, they reported in the Journal of the American Medical Association.
Meanwhile, a 10-year study of thousands of women found significantly fewer cases of cancer, including breast cancer, among those who were the most physically active.
But sleeping less than seven hours a night wiped out the benefits of exercise and increased the risk of cancer.
The researchers, from the U.S. government-funded National Cancer Institute, asked almost 6,000 women about their exercise and sleep routines before tracking their health for 10 years.