Why your teenager really is wasting their time in bed…. as 16-year-olds ‘only need seven hours sleep’

Despite long-maintained claims that teenagers require more rest, there has always been a lingering suspicion among parents that yougsters are wasting their time by spending half their day in bed.

Now, according to new research, mothers and fathers may indeed be right after scientists suggested the optimum amount of sleep for a typical 16-year-old is just seven hours a night.

Current health recommendations advise teens get nine or more hours.

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

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

But this could be two hours too much and – crucially – may lead to poorer exam results.

Scientists from Brigham Young University in Utah examined 1,724 primary and secondary pupils’ performances and compared them with the amount of sleep they got.

Reporting the findings in the Eastern Economics Journal, they said the right amount of sleep decreases with age.

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.

The optimum amount of sleep in nine to 9.5 hours, for 12-year-olds it is eight or 8.5 hours and for 16-year-olds it is seven hours.

Study author Eric Eide said: ‘We’re not talking about sleep deprivation. The data simply says that seven hours is optimal at that age.’

It is the first in a series of studies which examined sleep and its impact on our health and education.

Dr Eide said: ‘If a child is only getting 5.5 hours of sleep a night because he’s too busy, he would perform better if he got 90 minutes more each night.’

The size of the effect on test scores depends on a number of factors, but an 80-minute shift toward the optimum is comparable to the child’s parents completing about one more year of schooling.

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 realize that 9 hours of sleep isn’t what the top students do.’

The study also showed that those with regular patterns of sleep performed better than those who don't.

The effect of sleep has been studied over a wide range of subjects.

Among the latest research include suggestions that too little will kill male sex drive and that exercise – combined with a minimum of seven hours sleep – can ward off cancer.

Testing best: Pupils also do better in exams if they have a regular sleeping pattern

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 ten years.