Children who have trouble sleeping tend to do worse in
school than their peers who get a good night's sleep, a new study suggests.
Researchers in Brazil looked at children age seven to 10 who
attended Sao Paulo public schools. They found kids with symptoms of sleep
disorders or sleep breathing disorders earned lower grades than those without
problems sleeping, on average.
13% of children with difficulty sleeping had failing grades
in Portuguese, compared to 9%of those without sleep problems.
Likewise, 25% of kids
with disrupted sleep had failing math grades, versus 8% of children without
trouble sleeping. "Because [symptoms of sleep disorders] and particularly [sleep breathing disorders] are highly prevalent, we suggest that all health
professionals and educators become aware of this striking effect and take
appropriate actions to solve or mitigate what could very well constitute a
public health issue," researchers led by Luciane Bizari Coin de Carvalho
from the Universidade Federal de Sao Paulo wrote.
Experts estimate that roughly one-quarter of US children
have disrupted sleep at some point during childhood. Erratic bedtime hours and
anxiety, either at school or at home, may contribute. Other children may have
unrecognised sleep disorders, such as sleep walking, nightmares or insomnia, or
sleep breathing disorders, like sleep apnoea.
Some medications, including those for asthma or
attention-deficit/hyperactivity disorder, can affect sleep. The underlying
medical problems may also cause sleep disturbances. Poor sleep among children
has been tied to obesity, which in the long run increases the risk of heart
disease and diabetes. And poor school performance has been linked to early
dropout rates, so the new findings may have implications beyond getting a good
night's sleep, researchers said.
From 1999 to 2001, the researchers distributed 5 400
questionnaires asking about symptoms of sleep disorders and sleep breathing
disorders to children in Sao Paulo public schools. Then they looked at the Portuguese
and Math grades of 2 384 children whose parents filled out and returned the
questionnaire. The study team found about 31% of the children had symptoms
of sleep disorders such as difficulty
falling or staying asleep, or feeling sleepy all the time and close to 27% had sleep breathing
grades were significantly lower than the grades of kids without sleep disorder
symptoms. In Brazil, grades are based on a scale of 0 to 10, with 5 considered a
passing grade. Average Portuguese grades were 6.6 for kids with sleep problems,
compared to 7.1 among those with no sleeping trouble.
with symptoms of sleep disorders or sleep breathing disorders earned an average
grade of 6.3 in Maths, compared to 7.1 for other children, according to findings
published in the journal Sleep Medicine.
Importance of sleep
Dr Carl Bazil, a
neurologist and director of the division of epilepsy and sleep at New York
Presbyterian/Columbia University Medical Center in New York City noted that
this study fills a research void. "There's growing information, mainly in
adults, that you need good quality sleep to process and learn new
information," Bazil told Reuters Health. "It stands to reason that,
if anything, sleep would be more important in children, but there's very little
information in children about sleep disturbance and learning."Research has
shown that sleep deprivation might affect certain parts of the brain,
especially the frontal lobes. The frontal lobes control executive function, which is the
ability to make decisions, form memories, plan for the future and inhibit
socially undesirable behaviour like
fighting with a classmate. However, the new study can't say definitively that
sleep problems were to blame for poor grades, researchers said. "This
study doesn't prove that a sleep disturbance causes decreased academic
performance," Bazil said, "but it shows an association."
category of sleep disturbance the authors looked at correlated with decreased
academic performance."The researchers relied on parents' reports of their
children's sleep, rather than bringing kids into a sleep lab overnight, for
The study is "far from perfect", Bazil said. But,
"It's a first step in emphasising that sleep in children is something
that's important, not only to prevent them from being sleepy but to make sure
that they learn. I think this study will help raise awareness that sleep is
particularly important in children."