Is your child really getting enough sleep?
Times, September 2012
There is growing evidence that today’s children are sleeping less than previous generations
Worrying about how much sleep children are getting is hardly new: in 1908, the psychiatrist Sir James Crichton-Browne warned that “the evil of insufficient sleep in children is widespread”.
But there is growing evidence that today’s children – particularly pre-teens and teenagers – are sleeping less than previous generations. A recent survey of 4,000 parents by Travelodge revealed that the average bedtime for a 10-year-old was 10.30pm, rising to midnight for a 15-year-old; 74 per cent of their parents thought that seven hours a night was enough.
The No 1 culprit is technology: TVs and games consoles in bedrooms, and children taking their smartphones, laptops and iPod Touches to bed with them to message friends and download TV programmes on iPlayer.
This has the twin effects of pushing bedtime later and stimulating the brain at a time when it should be winding down. The bright light from the screen can also stop the body producing the hormone melatonin, which prepares us for sleep.
“We are increasingly seeing this in our clinic: children are switching off the hormone that allows them to sleep by their exposure to a bright light source, particularly the blue-green spectrum given off by computers and TVs,” says Gringras. “We don’t yet know how bright, for how long or how near you need to be, but studies show you need only a brief exposure – around two minutes – to a very bright light in the evening to put off sleep by two hours. Japanese research has found that the glow of a computer screen is enough if you sit close to it.”
Even a modest lack of sleep among older children has been shown to have startling effects: in an Israeli study of children aged 10 and 12, those told to sleep on average 41 minutes less than usual for several nights were then tested for memory, reaction times and attention and found to be the equivalent of two years behind their classmates, who got 35 minutes more sleep a night than usual.
A study of 3,000 US teenagers showed that those getting school marks between C and F were going to bed 40 minutes later than the students with As and Bs, and were also reporting more depressive moods.
The link with depression was strengthened by two surveys last year: Taiwanese researchers found that children with a bedtime of 10pm or later were far more likely to have symptoms of depression than those who went to bed earlier. And a study of teen sleep by the University of Arkansas revealed that those sleeping less than five hours a night were at the highest risk of suicidal feelings.
There are also documented links with obesity (seven-year-olds who sleep fewer than ten hours are twice as likely to be obese), future drug and alcohol abuse and other health problems such as cardiovascular disease and high blood pressure.
In fact, new research suggests that young teenagers may actually need more sleep than their younger siblings. “From about the age of 10 to puberty at 12 or so, their need for sleep drops slightly, but during adolescence research on the brain shows that it may increase,” says Professor Jim Horne at Loughborough University’s Sleep Research Centre. “During that time the brain undergoes a rewiring, especially in the centres governing emotions, rational thinking and planning ahead – and during this process they seem to need to sleep deeper and longerfor three or four years.”
Marathon weekend lie-ins are not the answer either, because teenagers’ body clocks are naturally moving later (a process that begins at 11/12 and doesn’t stop until the early twenties) and lie-ins push them even later. Experts recommend the difference between getting up on weekdays and weekends should be no more than two hours.
How much sleep is enough is much argued over. The UK has no national guidelines but the NHS publishes the recommendations set out by the children’s sleep clinic Millpond (see below). America’s National Sleep Foundation recommends 10-11 hours for children aged 5-12 and 9-10 hours for teenagers. Eminent specialist Professor Mary Carskadon, from Brown University, who has been researching children’s sleep since the 1970s, maintains there is enough scientific evidence to prove that teenagers need “at least nine” hours a night.
“Parents totally get it with infants and toddlers needing certain amounts of sleep, but are much less clear about the second decade of their child’s life,” she says. “It’s becoming a bigger and bigger problem: I think today’s adolescents are sleeping less than any previous generation.”
She agrees that it is difficult for parents to police. “It’s such a hard battle to fight in the trenches of the home: adolescence is the time when children are achieving more autonomy and going to bed later is one place they try to assert that. I would love for every home to have a lock-box for phones and computers where they could charge overnight. Everybody’s sleep would improve markedly, but that’s not going to happen.”
Mandy Gurney, co-founder of the Millpond children’s sleep clinic, believes parents forget that a bedtime routine is just as vital for older children as babies. “The rules about a gentle winding down routine are ingrained in parents of babies and toddlers, yet by the time they can put themselves to bed we don’t tend to think of it.
Parents will say, ‘time for bed’ and the children head upstairs with their phone or laptop quite happily while parentsget on with what they have to do. We think we’ve done our job, but they’re up there doing anything but sleeping.”
Her method for dealing with sleep-deprived teens is strikingly similar to much younger children. “I’ve just done the sleep programme with a 13-year-old boy and it was really going back to basics: a bedtime routine, a bath, turning the lights down, reading.”
Bedtime: the six golden rules
2 Limit screens: all screens off 30-60 minutes before sleep, and ideally devices should be on the landing a minimum of 30 minutes before sleep. Don’t be deceived if teenagers say their brains have evolved to ignore the phone in their room. “Anything in the bedroom will disturb you – people sleeping together always have poorer quality sleep than if they had slept alone and if we haven’t evolved to get used to that then it’s unlikely that we would have evolved to sleep with our smartphones,” Dr Chris Idzikowski, director of the Edinburgh Sleep Centre, says.
3 Don’t go to bed hungry, but don’t eat a full meal within an hour of bed, either, as the digestive process delays sleep. Foods containing the amino acid tryptophan (bananas, chicken/turkey, wholegrain cereals and milk) are often cited as a sleep aid although many scientists say there is little evidence for their efficacy. “Whether tryptophan works or not, a glass of milk and toast or an oat biscuit with a banana an hour before bed is a healthy snack, so you won’t lose anything,” Mandy Gurney says. Avoid foods with refined sugar and caffeine.
4 Don’t begin in-depth conversations about life, exams and the universe in the last hour before bed, as social interaction is the most potent brain stimulation that exists.
5 Stop exercising three hours before sleep. Body temperature begins falling around the onset of sleep, but exercise keeps it high and delays sleep. “Exercise keeps your body temperature high and it’s also a stressor for the body, which keeps you awake,” Idzikowski says.
6 Keep the same bedtime rituals; the body knows what to expect and relaxes. A hot bath followed by quiet reading is the best way to ready the body. Rooms should be cool, quiet and dark. “A regularity of routine is amazingly useful,” Idzikowski says.