THURSDAY, June 12 (HealthDay News) -- Teens whose high schools
have a delayed start time sleep longer and report less daytime
sleepiness, say researchers at Norwalk Hospital's Sleep Disorders
Center in Connecticut.
The study included 259 high school students who reported
sleeping about 7.03 hours per school night, with a mean bed time of
10:52 p.m. and a mean wake-up time of 6:12 a.m. when school started
at 7:35 a.m.
After the school start time was switched to 8:15 a.m., the
students' total sleep time on school nights increased 33 minutes,
mainly due to a later rise time. Their bedtime on school nights was
slightly later, and there was a slight decrease in weekend sleep
time. After the change in school start time, more students reported
having no problem with daytime sleepiness.
"Following a 40-minute delay in start time, the students
utilized 83 percent of the extra time for sleep. This increase in
sleep time came as a result of being able to 'sleep in' to 6:53
a.m., with little delay in their reported school night bedtime.
This study demonstrates that students given the opportunity to
sleep longer, will, rather than extend their wake activities on
school nights," study corresponding author Dr. Mary B. O'Malley
said in a prepared statement.
The research was expected to be presented at the annual meeting
of the Associated Professional Sleep Societies, in Baltimore.
In other study results expected to be presented at the meeting,
researchers found that teens who don't get enough sleep suffer
lower school grades and lack of motivation and are increased risk
for serious emotional and behavioral problems.
The University of Kentucky study of 882 high school freshmen
found that they slept an average of 7.6 hours per school night,
with 48 percent reporting less than eight hours.
The researchers found a strong association between hours of
sleep per school night and GPA, level of motivation, emotional
disturbance and attention-deficit hyperactivity disorder (ADHD).
Each additional hour of sleep on school nights reduced the risk of
scoring in the clinically significant range of emotional
disturbance and ADHD by 25 percent and 34 percent,
respectively.
"Since these findings are based on associations rather than
direct experimental manipulation, they cannot conclusively prove
that insufficient sleep causes a loss of motivation, poor grades,
ADHD and emotional disturbance during adolescence," study author
Fred Danner said in a prepared statement.
"These results, however, are consistent with a growing body of
research that many adolescents do not get sufficient sleep, and
that even mild chronic sleep deprivation has serious effects on
their psychological functioning. Lack of sleep should no longer be
considered a traditional adolescent rite of passage, because it can
have serious consequences," Danner said.
More information
The Nemours Foundation has more about
teens and sleep.
