We are sleeping fewer hours than ever before
The result is hyperactive children, increased levels of stress, poor
memory - and even obesity
April 28, 2004
How do you feel when you have not slept enough? Bit cranky? Lethargic?
Irritable? You can probably get through the day without losing the plot
completely, and either catch an early night or a lie-in at the weekend to make
up the deficit. But what happens if - as is often the case in our time-pressured
society - sleep deficit becomes chronic? Research published recently suggests
that not only are many adults suffering chronic sleep deprivation, but children
are too.
Many children regularly sleep an hour or two less than is recommended,
according to new research carried out by ICM on behalf of Horlicks, while
coincidentally a new report published by the National Sleep Foundation in the US
says the same. Part of the blame, both reports state, is the extended use of
computer games, PCs, or televisions in children's bedrooms - enjoyed by 67 per
cent of 4-10-year-olds in the UK. The distraction these provide is thought to
discourage children from settling down in time to get enough sleep before the
next morning.
The myth is that children will get the sleep they need, says Dr Luci Wiggs, a
research fellow at the University of Oxford's Child and Adolescent Unit.
"Parents may erroneously think that a child will take the sleep they need,
and will have sufficient self-awareness to know when they should settle to sleep
and resist the temptation of competing activities and pastimes. Would they
credit children with such self-awareness and discipline if they put a whole
chocolate cake in front of them and told them only to eat as much as they
should? Would it really be such a surprise that the child would eat until they
were sick?"
It's a modern conundrum, not just in terms of children getting the sleep they
need, but adults too. We are all sleeping less than even a decade ago, averaging
around seven hours' sleep a night rather than eight. Our forebears at the
beginning of the century averaged nine hours. Our 24-hour society means that
even if we don't utilise an all-night supermarket, the option is there, or we
can order online at 3am. There is no reason ever to stop working, online
shopping, watching TV or using internet chat rooms. But sleep isn't a social
inconvenience, it's a physical necessity and more and more studies are showing
that sleep deprivation is a growing problem.
The problem was highlighted as long ago as 1999, when research from the
University of Chicago Medical Centre was published in The Lancet. What made this
study interesting was that it was the first to examine the impact of chronic
sleep deprivation on the body by evaluating the metabolism and hormone secretion
of those subjected to sleep restriction over a period of time, and again after
sleep recovery.
We found that the metabolic and endocrine changes resulting from a
significant sleep debt mimic many of the hallmarks of ageing," said Dr Eve
Van Cauter, a professor of medicine and the director of the study. "We
suspect that chronic sleep loss may not only hasten the onset but could also
increase the severity of age-related ailments such as diabetes, hypertension,
obesity and memory loss."
One significant aspect of chronic sleep deprivation is the prolonged levels
of blood cortisol, which is known to be a neurotoxin and damaging to the brain
in large quantities. This effect on ageing, and memory loss in particular, comes
as no surprise to Dr Dharma, who runs a "brain longevity program" in
Tucson, Arizona. Dharma, who worked initially as an anaesthesiologist, studied
mind/body medicine at Harvard, before concentrating his interest on the effects
of the stress hormone, cortisol, on the brain.
"In moderate amounts, cortisol is not harmful," says Dharma. "But
when produced in excess, day after day - as a result of unrelenting stress -
this hormone is so toxic to the brain that it kills and injures brain cells by
the billions. I am not certain that chronic exposure of the brain to toxic
levels of cortisol is a primary cause of brain degeneration during the ageing
process. Over decades, excessive cortisol destroys the biochemical integrity of
the brain."
Dr Mark Blaygrove, who researches sleep loss at the University of Wales,
Swansea, has come to similar conclusions with his research on shift workers.
Night time workers in particular, seldom compensate for the sleep loss they
encounter and this, he believes, can contribute to heart problems on a long-term
basis.
"Heart problems are the main bodily problem we know about,"
Blaygrove comments. "We know now that if people are on restricted sleep
they have higher cortisol concentrations - the bodily chemical to do with
stress."
Anyone who watched the Channel 4 programme Shattered last year will have a
reasonable idea of the effects of chronic sleep deprivation, but even an hour
less a night can show a measurable effect on children's mental performance, for
example, as research published last year in Child Development by Dr Avi Sadeh
reported. Disturbed sleep patterns, where there is persistent night time waking,
has also shown to be linked to behavioural problems that resemble attention
deficit hyperactivity disorder, as well as learning problems. The increase in
the secretion of the hormones adrenaline and cortisol to compensate is thought
to cause this heightened activity and irritability. The good news is that
restoring better sleep patterns in these cases relieves many of these problems
and, in children with sleep problems who also show symptoms of failure to
thrive, restored sleep is associated with increased growth.
Dr Adrian Williams, director of the St Thomas' Hospital Sleep Disorders
Centre, is also concerned about the effect of sleep deprivation on physical
health. "We know from research published in The Lancet in 1999 that sleep
restriction leads to a diabetic tendency. Chronic lack of sleep increases the
level of the hormone adrenaline, which is linked to the development of insulin
resistance and diabetes. Generally there are a lot of people not getting enough
sleep, and I would be interested to see research on whether there is a link
between chronic sleep restriction and obesity. We are seeing a rise in people
sleeping less, and a rise in obesity, and the link already established between
sleep restriction and diabetes suggests this may be the case."
And in January this year, a report from Chicago, published in Child
Development, showed that 11-13-year-olds had increased rates of depression and
low self-esteem, and reduced academic performance, linked to disturbed sleep. A
study carried out by an accident and emergency unit in Italy identified that
reduced sleep in children aged 14 and under was associated with an 86 per cent
increased risk of injury.
So how can you tell if you or your child is getting enough sleep? The
simplest way is to assess how you feel when you wake. Do you feel tired when the
alarm clock goes off, or full of life? Do your children wake up happy in the
morning, or are they are grumpy and difficult to rouse? Another way is to take a
quick look at the estimated sleep needs of differently aged children, and how
that measures up. If your 4-year-old goes to bed at 9pm, and needs to get up at
7am, then the 12 hours recommended isn't going to happen. At 4 years, a child is
reckoned to need around 12 hours sleep every night; a 7-year-old needs 10 hours;
and a 10-year-old 8-10 hours. Occasional late nights won't matter much, but
regular lack of sleep can be as detrimental for children as it is for adults.
Plus, learning good sleep patterns in childhood stands us in good stead for
adult life.
It's not just the quality of sleep that's important, but also the quantity,
says Wiggs. "There are two main types of sleep: rapid eye movement (REM)
sleep, or non-rapid eye movement sleep (NREM), which is further divided into
light and deep sleep. Deep sleep, or slow wave sleep (SWS) coincides with the
release of growth hormone in children and young adults, and occurs mainly in the
first half of the night, while REM sleep is seen predominantly in the second
half of the night, both of which are important for memory consolidation. So
while it's possible to get most of the SWS with reduced sleep, without the
duration of sleep then it is probable that you will miss out on some of your REM
sleep."
"What we do know," says Wiggs, "is that impaired sleep quality
or quantity may compromise children's health, academic achievements and mental
health. With all indications suggesting that the 24/7 society is here to stay,
shouldn't we be worried? Shouldn't attention be paid to promoting good sleep
habits in young people in an attempt to overcome some of the adverse effects of
the modern world?"
HOW TO AVOID THE LATE-NIGHT LIFESTYLE
