This document discusses adolescent health issues related to school start times. It notes that circadian rhythms cause teenagers' sleep-wake cycles to shift later in the day, making early school start times disruptive to their sleep and health. Studies show later start times improve sleep duration, safety, mental health, academics and more. While some schools were initially concerned later times would increase costs, many districts found moving to later middle and high school starts to be cost-neutral or cost-saving due to transportation efficiencies.

1. Adolescent Health
and Later School
Start Times
Ashland School Start Times Committee
Isha Ann Emhoff, MD FACS

2. Later School
Start Times
“Given that the primary focus of education is to maximize human
potential, then a new task before us is to ensure that the conditions in
which learning takes place addresses the very biology of our
learners.” Mary Carskadon, PhD Brown University

3. Circadian Rhythm
• Circa Diem: around the day
• Biologic endogenous time: “built in clock”
o Genetic
o Brain hypothalamus
• Suprachiasmatic Nucleus (SCN)
• What is the purpose?
o Allows anticipation and preparation for precise and regular
environmental changes
o Regulates metabolic processes
o Brain wave activity
o Temperature regulation
o Hormone production (cortisol)

4. Melatonin Secretion Changes
Child to Adolescent

5. Rhythmic Sleepy Time
Source: Adapted from data given by
National Sleep Foundation

6. Why Does Melatonin
Rhythm Matter?
• Waking a teenager
at 7:00 am is like
waking an adult at
4:00 am

7. Pubertal
Time Bending
• Sleep-Wake Phase Delay
o 2 hour delay relative to mid-childhood
o Fall asleep later and wake up later
• Delayed nocturnal melatonin secretion
o Shift in circadian phase preference
o Cannot just go to bed earlier – they cannot fall asleep
o High level of alertness at 8 PM, even higher at 10 PM
• Altered sleep drive
o Pressure to fall asleep accumulates more slowly
o Takes longer to fall asleep
o Difficulty falling asleep until after 11:00 PM

8. Sleep Time Delay
• Students lose up to 120 minutes of sleep per school
night1
• Weekend Catch-up Sleep
o Moves their inner clock even further away from the external clock
o Worsens morning sleepiness at school
• Keep the weekday schedule on weekends
• No napping
• Equivalent to 5 hours jet lag on Monday morning
1. Martha Hansen, et al.
The Impact of School Daily Schedule on Adolescent Sleep
Pediatrics 2005; 115:6 1555-1561

9. Optimal Timing
• 8.5-9.5 hours per night
• 11:00 PM bedtime
• 8:00 AM wake time

10. Where do the Hours Go?
Late school start time
schedule
o Alarm sounds at 7:30am
o Bus stop 8:20am
o School 9:00am to 3:50pm
o Stay at school
o Load buses for travel to away
game at 4:30pm
o Game 7:00pm to 9:00pm
o Home between 9:45 pm to
10:30pm
o Homework 10:30pm to 12:30am
o Bed 12:30 am or 1:00am
• Sleep 6.5 to 7 hours
Early school start time
schedule
o Alarm sounds 5:30am
o Bus stop 6:20am
o School 7:00am to 1:50pm
o Return home on bus 2:15pm
o Back to school to travel to
away game 4:30pm
o Game 7:00pm to 9:00pm
o Home between 9:45pm to
10:30pm
o Homework 10:30pm to 12:30am
o Bed 12:30 or 1:00am
• Sleep 4.5 to 5 hours

11. •Cognitive deficits
• Impaired executive function
•Deficits in abstract thinking
and verbal skills/creativity
•Decreased performance
efficiency and output
•Lower academic
achievement
•Poor school attendance
• Increased dropout rates
•Drowsy driving
• Increased sports injuries
• Increased Anxiety,
Depression, Suicidal Ideation
•Poor impulse control
• Increased risk-taking
behavior
•Emotional Dysregulation,
lowered affect
• Impaired interpretation of
Social Cues
• Increased stress vulnerability
•Decreased motivation
• Increased obesity risk
•Metabolic
•Hypercholesterolemia
•DM2
• Increased CV morbidity
•Non-medical use of
stimulants
• Reduced physical activity
Physical Mental
Safety Academic

12. Academics
Data from USAFA Policy Changes
• Starting the school day 50
minutes later has a
significant positive effect on
student achievement
• Improved performance is
not just a “wake up” effect
from later start.
• Improvement persists in all
classes throughout the day.
Carrell, Scott E., Teny Maghakian, and James E. West. "A's from Zzzz's? The causal
effect of school start time on the academic achievement of adolescents." American
Economic Journal: Economic Policy 3, no. 3 (2011): 62-81.

13. Teen Safety
• Automotive Crash
Rates
o Crash rates reduced 65-70%
(Wahlstrom et al, Univ. MN, 2014)
o Crash rates reduced 16.5%
while rest of state actually
increased 7.8% over the same
period. (Danner & Phillips, J. Clin Sleep
Med, 2008)

14. Teen Injuries
• Less than 8 hours sleep
1.7 times more likely to
suffer sports injury
• Risk increases 1.4 times
for each year grade
increase (7-12)
o Milewski J Pediatr Orthop. 2014

15. ADOLESCENT SLEEP WORKING GROUP, COMMITTEE ON ADOLESCENCE
and COUNCIL ON SCHOOL HEALTH
Pediatrics 2014;134;642; originally published online August 25, 2014; DOI: 10.1542/peds.2014-1697
http://pediatrics.aappublications.org/content/134/3/642.full.html
“The AAP is making a definitive and powerful statement about the importance of sleep to
the health, safety, performance and well-being of our nation's youth,”
“By advocating for later school start times for middle and high school students, the AAP is
both promoting the compelling scientific evidence that supports school start time delay
as an important public health measure, and providing support and encouragement to
those school districts around the country contemplating that change.
Judith Owens, MD, FAAP, lead author of the policy statement
• Aim for 8.5 – 9 .5 hours of sleep
• Middle and high school start 8:30 a.m. or later

16. Ohio Schools and Cost-Savings or Cost-Neutrality in Moving toward Healthier Start Times
(2013 data, per school websites)
Hudson City Schools, Ohio:
Suburban NE Ohio - total student enrollment: 4,700
4 elementary schools, 1 middle school, 1 high school
Percentage of graduates attending college or university: 95%
In 2010 school year: Moved high school from 7:30 to 8:00 and middle school from 7:20 to 7:50 am
Saved money by moving from three bus tiers to two, consolidating runs, and switching to an external vendor
Dublin City Schools, Ohio:
Suburban Central Ohio (near Columbus) - student enrollment in excess of: 14,500
10th largest district in the state
12 elementary schools, 4 middle schools, 3 high schools
Minority student population: 30.7%
Average ACT score of 25.2
In 2011 school year: Moved middle school from 8:15 am to 8:43am, high school from 7:25 am to 8am
The move was cost-neutral in relation to start times, but saved money due to other transportation changes made
Kenston Local Schools, Ohio:
Rural NE Ohio - total student enrollment: 3,140
3 elementary schools, 1 middle school, 1 high school
Percentage of graduates attending college or university: 94%
In 2012 school year: Moved middle and high school start times from 7:20 am to 7:50 am
The end of the school day for middle and high school was moved to 5 minutes later
The move was cost-neutral
Westlake City Schools, Ohio:
Suburban NE Ohio (Greater Cleveland Metropolitan Area) - student enrollment approximate: 4,000
4 elementary schools, 1 intermediate school, 1 middle school, 1 high school
In top 4% of districts in state scorecard rankings
In 2011 school year: Moved high school start times from 7:30 to 7:55am
The move was cost-neutral
Perrysburg Schools, Ohio:
Suburban NW Ohio - student enrollment in excess of: 4,900
4 elementary schools, 1 junior high school, 1 high school
Average ACT score 23.8
In 2011 school year: Moved high school from 7:40 to 8:00am, middle school from 7:25 to 7:45 am
The move was cost-neutral
Parma City School District:
Suburban NE Ohio (Greater Cleveland Metropolitan Area) - total student enrollment: 11,470
8 elementary schools, 3 middle schools, 3 high schools
In 2012 school year: High school moved from 7:35 to 8:10 am, middle school from 8:00 to 8:20 am
Move was driven by financial considerations and building consolidation, not driven by the research, although the research was ‘not discouraging’ in decision-making processes