The Impact of School Start
Times on Adolescent Health
and Academic Performance
Presented by Your Name
Phase Delay
ϑ Begins with
the onset of
puberty
ϑ The sleep/wake pattern
undergoes a biological delay
in the timing of sleep.
“ ‘Early to bed, early to rise’—
may be difficult in the
presence of a biologically
driven phase preference.”
---Mary Carskadon, et al.
(1993)
The adolescent
sleep pattern
runs from
about 11 p.m.
to 8 a.m. and
is “rather fixed.”
“Sending kids to school at 7 a.m.
is the equivalent of sending an
adult to work at 4 in the
morning.”
---William Dement, M.D., Sc.D., Ph.D.,
Professor of Psychiatry and Behavioral
Sciences, Stanford University School of
Medicine, Division Chief, Stanford
University Division of Sleep.
“All of the research that has been done
shows that older adolescents need more sleep
than younger ones. They fall asleep later and
wake up later to get the sleep they need.
Despite these two facts, almost all districts
start the senior high schools first. We’re
sending them to school during the last onethird of their sleep cycles. It’s comparable to
adults getting up at 3 a.m. or 4 a.m. You
wouldn’t want to be making important
decisions at that hour. I think it’s nuts. The
sleep deficit builds up until they fall asleep at
school or driving.”
Adolescent Sleep Needs
<8 = Insufficient
8 = Borderline
~8.5 hours = Adequate
~9.2 hours = Optimal
Older adolescents need
9-10 hours
Across species, maturing
individuals sleep more than fully
mature individuals.
ϑBrain maturation
ϑExtensive brain
rewiring
ϑRelease of growth
hormone
“Almost all teenagers in
this country are sleepdeprived.”
---Maida Chen, Assistant Professor
of Pediatrics, University of
Washington School of Medicine,
Assistant Director, Pediatric Sleep
Disorders Center, Seattle Children’s
Hospital.
Weeknight Sleep Deprivation
Prevails Among Teens
2011 National Sleep
Foundation Poll:
14% of teenagers
between the ages of 13 and 18
report getting nine or more
hours of sleep on weeknights
“Sleep deprivation among
adolescents appears to be,
in some respects, the norm
rather than the
exception in
contemporary
society.”
“Our study does
confirm that on
school days
adolescents are
obtaining less sleep then they
are thought to need, and the
factor with the biggest impact is
school start times.”
”Abusive”
--Mary Carskadon, Ph.D.
”Deleterious”
--Janet Croft, Ph.D.
”Nonsense”
--Till Roenneberg, Ph.D.
”It is cruel to impose a cultural
pattern on teenagers that
makes them underachieve.”
---Russell Foster, Ph.D., F.R.S.,
Chair of Circadian
Neuroscience,
Oxford University
Suprachiasmatic Nucleus (SCN)
The SCN is
primarily
responsible
for regulating
the circadian
rhythm, the
body’s hardwired internal
‘clock.’
Circadian Timing
Light incident on
human retinas
entrains or phase
shifts SCN timing.
Work/rest
schedules which
conflict with the circadian rhythm
result in circadian desynchronization.
Modifying Adolescent
Circadian Timing
Carefully control
light exposure
Including wearing
eyeshades to
exclude evening
light
“The issue of under-sleeping in
adolescents takes on added
significance when one considers
that waking up too early costs the
sleeper mostly REM sleep which
predominates
during the last two
to three hours of a
night’s sleep.”
Sleep Debt Can Mimic
ADHD
Similar Symptoms:
δ Distractibility
δ Impulsivity
δ Difficulty with
effortful control
of attention
Some Effects of Sleep Debt
Decreased ability to
regulate emotions
and behavior
 Poor grades and
school performance
 Increased
depression, anxiety,
and fatigue
 Reduced immunity
to illness.

Roper v. Simmons (2005)
“Risk-taking is a
complex
phenomenon, and
adolescents seem to
be a particularly
vulnerable
population.”
More Effects of Sleep Debt
δ Increased criminality
δ Increased caffeine consumption
δ Increased health-risk behaviors:
δ Cigarette use
δ Marijuana use
δ Alcohol use
δ Sexually active
δ Feeling sad or hopeless
δ Seriously considering
attempting suicide
Young people between 16 and 29
years of age are the most likely to
be involved in crashes caused by
the driver falling asleep.
Crash rates have
fallen substantially
in districts
starting school at
8:30 a.m. or later.
Additional Effects of Sleep Loss
ϑ
ϑ
ϑ
ϑ
Excessive weight gain
Elevated blood
pressure
Interference with
secondary brain
development
Physical,
psychological, or social
difficulties
CDC Study (2010)
“Delaying school
start times is a
demonstrated strategy to
promote sufficient sleep
among adolescents.”
“The results were stunning.
There’s no other word to use.
We didn’t think we’d get that
much bang for the buck.”
---Patricia Moss, M.A., Ph.D.,
Assistant Head of School and
Head of the Latin Department, St.
George’s School, Rhode Island.
Later Start Time Studies –
Outcomes:
δ Higher attendance rates
δ Higher graduation rates
δ Fewer tardy students
δ Fewer trips to the nurse’s office
δ Students report feeling more motivated
δ More hot breakfast meals consumed
δ Administrators report greater “calmness”
in the student body
Later Start Time
Studies – Outcomes
δ
δ
δ
δ
δ
δ
Kids get more sleep
Fewer reports of depression
Kids watch less Television
Attention levels improve
Less impulsivity
Better “rates of performance”
Sleep and Sports
Sleep extension (i.e., extra
sleep) results in:
δ Faster reaction times
δ Improved skill execution
δ Improved peripheral vision
δ Peak athletic performance
Academics and Later Start Times
δ 60 minute delay:
Edwards found a 3%
gain math and reading
scores
δ 50 minute delay:
Carrell, et al., found a
0.15 standard deviation
improvement in
student achievement
Brookings Institute Report
δ 9 a.m. start time: 0.175 standard
deviation improvement in academic
achievement
δ 9 to 1 benefits to cost ratio
to change start times
δ $17,500 increase in student earnings
Obstacles to Later Start Times
1. Transportation
2. After School Activities
3. Other Students and
Programs
4. Reduced Time to
Access Public
Resources
5. Teachers
6. Stress for Families
7. Uneducated Community
8. Resistance of students
Sleep Hygiene
ϑ Dim lights before bedtime
ϑ Go to bed at the same time every night
ϑ Turn off electronic devices 1-2 hours before
bedtime
ϑ Limit electronic devices in the bedroom;
eliminate TV’s and computers
ϑ Finish dinner at least 2 hours before sleeping
ϑ Calming activities before bedtime
ϑ Limit caffeine consumption
ϑ Get plenty of exercise – but finish at least 4
hours before bedtime
“Rather than the ‘early to bed...’
adage, the new adage should be,
‘Wake up later and your grades
will be greater.’”
---James Maas, Ph.D., Retired
Professor of Psychology, Stephen
H. Weiss Presidential Fellow,
Cornell University.
The End