Older Children May Go to Bed Later, Sleep Less, Feel Drowsier
May 31, 2000 -- Parents have long suspected it, and a new study bears it
out: Even before they hit their teens, school-age children start going to bed
later, sleeping less, and feeling drowsier during the day.
In addition to finding that sleep patterns change as children get older, the
study, published in the journal Developmental Psychology, found that
children in families with high stress levels are more likely to sleep poorly.
The findings are important, experts say, because too little sleep can cause big
problems for schoolchildren.
"We're not always aware of them, but sleep disturbances can have adverse
effects on learning, attention, and behavior," says study author Avi Sadeh,
DSc, senior lecturer and chairman of child psychology at Tel Aviv University in
Sadeh explored sleep patterns among 140 children in second, fourth, and six
grades. Participants wore wrist monitors for five consecutive school nights.
They also completed a survey about sleep habits, along with their parents, and
kept daily logs on daytime sleepiness.
Sleep measures included the time the child went to sleep, the time of
wakening, number of awakenings, and length of motionless sleep. Poor sleep was
defined as a period of sleep with more than 10% wakefulness, or waking more
than three times per night.
On average, older children went to bed later, slept less overall, and had
shorter periods of true sleep than younger children, with sixth graders
sleeping an hour less than second graders. The researchers also found that
girls had fewer awakenings and more motionless sleep than boys.
Doctors say sports, homework, and the Internet often keep children up. But
"in terms of learning and development, sleep is just as important as
extracurricular activities," says Gary Montgomery, MD, director of the
sleep center at Scottish Rite Children's Hospital and clinical assistant
professor of pulmonology at Morehouse School of Medicine, both in Atlanta.
Over time, late bedtimes cause body rhythms to shift. "In a few years,
bedtime can get delayed until 3 a.m., causing major disruptions in academic
performance and family life," Montgomery says. "So we retrain sleep and
wake cycles so that kids get at least eight hours on a regular basis."
School-age kids need 10 to 12 hours of sleep to restore the energy needed
for growth, Montgomery says. "You can tell that kids need more sleep when
they struggle to get out of bed, nap after school, and have poor
concentration," Montgomery says. "In fact, some kids are just plain
Fortunately, there are some simple ways to promote good sleep habits.
"Move bedtime up slowly, by a half hour a night," Montgomery says.
"Then gradually wind down activity and start bedtime rituals an hour
beforehand. For younger kids, warm baths, snacks, and stories are often
These same techniques apply to adolescents. "My daughter got her days
and nights mixed up, so now we're trying to reset her internal clock," says
Tonia McCoy-White, mother of 15-year-old Fetausha. "Her room is just for
sleep now, not doing homework or watching TV. And there's no napping during the
Other good "sleep hygiene" techniques, experts say, include exposure
to bright light during the day, limiting caffeine intake, darkening the room
for sleeping, and a regular bedtime.
The study was supported by the Israel Ministry of Education and by Helene
and Woolf Marmot.