One-fourth of overweight children may have sleep problems
that regular physical activity can largely resolve, researchers say.
Research shows a
surprising 25 out of 100 overweight, inactive children tested positive for
sleep-disordered breathing, including telltale snoring.
After about
three months of vigorous after-school physical activity such as jumping rope,
basketball and tag games, the number of children who tested positive for a sleep
disorder was cut in half, according to lead researcher, Dr. Catherine L. Davis.
In children who exercised the longest, the number was reduced by 80 percent.
In fact
researchers found the average score for all children who exercised - even those
who did not test positive for sleep disorders - improved on the Pediatric Sleep
Questionnaire.
When
Georgia researchers first gave the Pediatric Sleep Questionnaire, which looks at
symptoms of sleep disordered breathing - such as snoring, loud breathing and
daytime inattentiveness - they were surprised as well by how many children
tested positive.
The questionnaire, given to parents, has been shown to
provide results similar to those of polysomnography, a monitoring of
physiological activities such as breathing during sleep. "We asked parents about
caffeine intake, medications, usual bed and wake times to see if the children
are chronically sleep-deprived, asked if they had a tonsillectomy because that
usually fixes sleep apnea in children," Dr. Davis says.
Interestingly
sleepiness was not an issue because children instead tend to display attention
deficit/hyperactivity disorder-type behavior when they don't get enough sleep,
she says. Caffeine intake also may have played a role in subverting sleepiness,
the researchers say.
Also, the body mass index, based on height, weight,
age and sex, did not improve as children exercised and became asymptomatic.
However the growing children got fitter, built muscle and lost fat, Dr. Davis
says. "It affects their fatness, their fitness, their cardiovascular risk
factors, it's just their weight doesn't go down without a change in diet, just
like adults," she says. Adult studies have shown a similar relationship between
obesity and sleep apnea and how exercise can ameliorate sleep apnea.
"Kids can have sleep apnea for a
couple of reasons," she says. "A normal-weight child can have sleep apnea
because they have big tonsils and adenoids and many times their problems can be
cured with surgery."
Gaining weight can exacerbate sleep problems or
even cause them by contributing to a narrowed airway, she says. The child lies
down, throat muscles relax, the tongue falls back, the airway gets obstructed,
oxygen levels may drop, the child is aroused and the cycle begins again.
Snoring, present in essentially everyone with sleep apnea, results from the
vibration of excess tissue - whether it's fat, large natural anatomy or both -
as the child breathes in.