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Too much small-screen recreation could undermine
physical fitness, Australian researchers have found, in a new
study that looks at how e-mail and text messaging, TV,
videogames and net surfing affect aerobic endurance in
adolescents. Two hours of daily screen
time appears to be the "cut point" above which kids are
significantly less likely to be fit, found researchers led by
Louise Hardy, Ph.D., at the New South Wales Centre of Overweight
and Obesity at the University of Sydney.
"The effect was consistently stronger among
all girls compared with boys," Hardy said. "The longer girls
spent on screen recreation the less fit they were, and the
evidence of this effect increases with age among girls."
Older boys were less affected, no matter how
long they spent on screen recreation.
The study doesn't confirm cause and effect: It
might be that small screens do lure kids away from active play,
or it could be that fit kids are less likely to plop down in
front of a screen in the first place.
Past studies have looked at the effects of TV
viewing on fitness, but not other forms of electronics that can
turn kids into couch potatoes. The new study appears in the
February 2009 issue of the American Journal of Preventive
Medicine .
The research team surveyed 2,750 New South
Wales students on their physical activity and screen use. They
also put students through the "pacer" test, a shuttle run that
physical education teachers use to measure fitness.
"Among younger boys in grades six and eight,
fitness levels were lower as their screen time increased, but
this was not apparent among older boys," Hardy said. She added
that although the10th-grade boys reported the most screen time -
some as much as 10 hours a day - and finished 20 percent fewer
laps than other boys in their age group, that result was not
statistically significant.
"We think these boys, who would be 15 to16
years old, probably have developed enough muscle mass which
allows them to sit and be fit," Hardy said.
Guidelines from American Academy of Pediatrics
and Healthy People 2010 call for kids to keep viewing to a daily
maximum of two hours.
American kids are more sedentary than their
Australian peers, said James Sallis, Ph.D., a physical activity
researcher at San Diego State University: "I've seen six to six
and a half hours per day of recreational screen time in the U.S.
Based on that, we might expect to find that the fitness
situation is worse here."
Still, the lure of the sedentary is strong,
Sallis acknowledges: "There's a lot of money involved in getting
kids glued to the screen. It's like candy to a baby: lots of
color, motion and flash to get them mesmerized."
Sallis said that parents have become more
reluctant to encourage their kids to play outdoors due to fears
of traffic risks and "stranger danger" - although the risk of
such abduction is minimal. "As a consequence, parents increase
the risk of low fitness and obesity, which is extremely common."
Hardy said the take-home message is to
encourage "all kids to exchange some screen time for active
time," and for parents to "keep kids screen time under two hours
a day, and aim for 'no-screen' days." |
