Not getting enough shut-eye each night may
play a role in youngsters becoming overweight,
partly by disrupting normal metabolism, a
doctor from the University of Bristol, UK,
contends in a report released.
Although there is a "strong genetic contribution
to obesity," the current epidemic of obesity
has been driven largely by environmental factors
-- an unhealthy diet and a lack of physical
activity -- Dr. Shahrad Taheri points out
in the Archives of Disease in Childhood.
Moreover, there is an emerging body of research
that suggests that sleep may impact energy
balance and that short sleep duration may
lead to metabolic changes that could help
fuel the development of obesity, diabetes
and cardiovascular disease.
Laboratory studies hint that as little as
two to three nights of too little sleep in
young adults can have profound negative effects
on fat hormones.
In one study, for example, the hormone ghrelin,
which is released by the stomach to signal
hunger, was nearly 15 percent higher in people
sleeping only five hours per night versus
the generally recommended eight hours.
Inadequate sleep disturbs other hormones
as well, including insulin, the stress hormone
cortisol, and growth hormone, which could
boost the desire for fatty foods.
Short sleep duration affects not only energy
intake, but energy expenditure as well, since
it results in tiredness that may curb physical
activity levels.
Links between sleep deprivation and obesity
seem to be particularly robust in children,
Taheri notes, "in whom there is a linear dose-response
relationship between shorter sleep and increased
body weight."
In general, children and adults are sleeping
less today than in years past, Taheri also
points out, and the decline in nightly hours
of shut-eye coincides with the rise in obesity.
Taheri blames diminishing sleep duration
on computers, cell phones, TVs and other gadgets
-- all of which have become readily available
to children and are increasingly found in
their bedroom. Removing these devices from
the bedroom and keeping strict bedtimes are
essential to promoting adequate sleep and
healthy sleep habits among children and adolescents,
Taheri believes.
Getting an adequate amount of sleep each
night may not be the only answer to skyrocketing
rates of overweight and obesity among today's
youth, "but its effect should be taken seriously,"
Taheri writes.
Good sleep, coupled with a healthy diet and
plenty of physical activity, "could be part
of the obesity prevention approach," Taheri
concludes.
SOURCE: Archives of Disease in Childhood,
November 2006.
