The Science of Sleep

Sleep Patterns

Weekdays:

• What time do you go to bed?

• What time do you wake up?

Weekend days:

• What time do you go to bed?

• What time do you wake up?

Do you think you get enough sleep?

Question # 8

Sleep is a time for the body and brain to shut downfor rest.

Disagree

Sleep is a dynamic process: Some increased brain activity Endocrine systems increases secretions of certain hormones

What is sleep video

How much sleep did you get last night?

How much should you have?

How much should a teenager have?

Would you believe 9 to 10 hours?

Agree

Teens do need at least 9 hours of sleep per nightTeens need more sleep than adultsMost teens do not get enough sleep

Question # 6Most teens need at least nine hours of sleep each night.

Did you know?

• 85% of adolescents get less than recommended sleep on school nights

• 56% of teens report getting less sleep than they need

• By 12th grade average sleep on school nights is 6.9 hrs.– By end of week sleep debt = 10.5 hours

Good Sleep

• Healthier

• Attractive

• Taller

• Stronger

• Faster

• More athletic

• Smarter

NSF poll• 28% fall asleep at least one time per week• 22% fall asleep doing homework• Less sleep

– Lower grades– Depressed mood

• “A” Students– Sleep 15 min more than B students– 26 min more than C students– 36 min more than D students

• Teachers were able to predict students sleep amounts by academic and classroom behavior

Attention Deficit Hyperactivity Disorder

Primary Symptoms of ADHD

• Hyperactivity

• Inattention

• Impulsivity

• Distractibility

• Difficulty concentrating

• Forgetful

• Difficulty waiting or taking turns

Sleep Deprivation in Kids

• Hyperactivity

• Inattention

• Impulsivity

• Distractibility

• Difficulty concentrating

• Forgetful

• Oppositional behavior

• Moodiness and irritability

Did you know?

• It is estimated that at least 50% of kids diagnosed with ADHD actually have sleep disorder.

Why is sleep important?

• Memory

• Concentration

• Motor response/reaction

• Controlling emotions

• School/work/athletic performance

Sleep Regulation

Regulated by:

• Circadian system (Biological clock)

• Homeostatic mechanism

Sleep variables:

• Duration

• Sleep intensity

(Tobler and Achermann)

Sleep Cycles

1. Biological clock – when

2. NREM/REM – how

3. Sleep Homeostasis - need

Question #1

Everyone has a biological clock.

True

The timing of sleep in humans is regulated by our biological clock

(1) Biological Clock

• Cycle: a little longer than 24 hour period “CIRCADIAN CLOCK”

• circa=about • diem=day

• Clock Regulates:– Seasonal reproductive cycles– Sleep/wake cycles

• External and internal rhythms.

Question # 9

The body quickly adjusts to different sleep schedules?

False

Circadian clock works on day/night schedule, despite attempts to change it

Clock can sometimes be reset, but only by an hour or two.

(1) Biological Clock

Circadian Rhythms

Two Clock Rhythms

External (environmental) rhythm

Internal rhythm

(1) Biological Clock

Clock location: suprachiasmatic nucleus (SCN) of the hypothalamus in the brain

At SCN signals interact with genes (active/inactive) to serve as “pacemakers”

External rhythmLIGHT

(1) Biological Clock

http://en.wikipedia.org/wiki/File:Circadian_rhythm_labeled.jpg

Internal rhythm

Rhythm continues in absence of environmental cues

Cycles just over 24 hours, bedtime 1 hour later each night.

24 days back to same bedtime.

Biological Clock Video

(1) Biological Clock

(2) NREM/REM (Ultradian Rhythm)

Slow wave - Non Rapid Eye Movement (NREM)

Rapid Eye Movement (REM)

NREM• Slow wave

– Low muscle movement

– Limited eye movement

(2) NREM/REM

Brain distributes information into networks & categories. (FRONTLINE)

Connections between nerve cells strengthen - consolidating new skills. (FRONTLINE)

REM• REM

– Burst of rapid eye movement– Almost paralyzed

(2) NREM/REM

Brain re-enacts previous day(FRONTLINE)

Solidifies newly made connections through memory banks (FRONTLINE)

Practice makes perfect!!

Nova Sleep Video

(2) NREM/REM

What happens when you don’t sleep?

Consequences of Sleep Deprivation• Cognitive and social impairment• Decreases ability to think

– Creative– Problem solving– Abstract thought– Decision making/judgement

• Mood and depression• Reduced endurance• Increased risk seeking behavior• Impaired motor function

– Decreased coordination– Blurred vision– Prolonged reaction time

• Delayed visual reaction time• Delayed auditory reaction time

Fatigue vs. Alcohol

17 hours sustained wakefulness produces performance impairment = .08% BAC

24 hours = .10% BAC (Dawson & Reid, 1997; Williamson & Feyer, 2000).

Synergistic effectOn 4 hours sleep, 1 beer can have the impact of a six-

pack (Roehrs et al., 1994)

*Approximate breath ethanol concentration (BrEC) at peak; †Above 0.05% for legal intoxication in many states. N=32 healthy subjects without prior sleep deprivation and with 85% sleep efficiency. Sleep loss group (n=12) was tested in all 4 conditions, with 3 to 7 days of recovery time between tests, and compared with ethanol group (n=20).Roehrs T, et al. Sleep. 2003;26:981-985.

BrE

C, %

*

Sleep time (hours in bed)

0.045

0.095 0.102

0.190

0.00

0.05

0.10

0.15

0.20

6 4 2 0

Legal In

toxication†

Hours of Sleep and Equivalent Blood Alcohol Level for Sedative Effects

Why don’t you get enough sleep?

Not a priority

Not enough sleep

• Sleep just is not set as a priority– School– Homework– Sports– Social life– Television– Internet– Etc all get in the way

They want to sleep, but aren’t able

• Their internal clock is shifted several hours later.– Bedtimes shifts to 11-1am

• Trying to go to bed at 10 is similar to adult trying to go to bed at 8 pm

– Wake up times shift accordingly • Shortened sleep time

Junk sleep

• 98.5% have at least one electronic device in their bedroom (TV, Phone or mp3 player)– 65% had all 3– Greater number of items

• Less amount of sleep

• Greater amount of daytime sleepiness

Sleep Disorders

• Obstructive sleep apnea syndrome

• Restless Legs/Periodic Limb Movement

• Parasomnias

• Insomnia– Stress/worry/body clock

Tips to help sleep

• Make sleep a priority!!!!!• Establish regular sleep schedule and routine

– Encourage relaxing, non-alerting activity• Read• Write • Avoid TV and PC

• Make Bedroom a NO gadget zone.– Place recharging station in kitchen not bedroom.

• Avoid Caffeine. • Expose yourself to light in the morning.• Exercise, but not too close to bedtime.• Avoid late naps

(3) Sleep Homeostasis(Homeostatic “rhythm”)

Homeostasis: maintaining internal equilibrium by adjusting internal processes

Sleep pressure increases when awake

Sleep pressure decreases during sleep

Sleep HomeostasisMolecule Adenosine:

•Keep tracks of sleep loss•May induce sleep

Caffeine binds and blocks receptors

Hormone melatonin:•Levels rise during the night•Levels decline at dawn

Controlled by the clock

(3) Homeostasis

Sleep Homeostasis Video

Circadian patterns typical of someone who rises early in morning, eats lunch around noon, and sleeps at night (10 p.m.) http://commons.wikimedia.org/wiki/File:Biological_clock_human.PNG .

1) Biological Clock - when 2) NREM/REM - how3) Homeostasis - need

Sleep Cycles

Why is sleep important?

• Memory

• Concentration

• Motor response/reaction

• Controlling emotions

• School/work/athletic performance

Question #10

Getting one hour less sleep per night than I need will not have any effect on my daytime performance.

False

small, regular, decreases can effect daytime performance.

What are good and bad sleep habits?

Good Sleep Habits Bad Sleep Habits

What are some consequences of bad sleep habits?

Individually Socially

Question #3

Safe drivers don’t have to worry about being sleepy?

False

Sleepiness = decrease in alertness

Decrease in alertness ≠ safe driving

Question # 7

Driving makes you sleepy.

False

Driving makes your level of sleepiness apparent

Safest to drive during alert times

Sleep Prepares for Learning

Too little sleep impairs information acquisition

– Sleepiness

– Irritability

– Distractibility

– Inattention

– Motivation

• That is, ability to process input is diminished

ReferencesUnless otherwise noted within the presentation, information, charts and graphs have been obtained from NIH Curriculum Supplements for Grades 9-12. Sleep Disorders and Biological Rhythms.

1. NIH Curriculum Supplement Series for Grades 9-12. Sleep Disorders and Biological Rhythms. National Institutes of Health http://science.education.nih.gov/customers.nsf/HSSleep?OpenForm

2. FRONTLINE. Adolescents and Sleep, A Summary of What Researchers Know About Teenagers’ Need for Sleep and Why Sleep Affects Memory and Learning. http://www.pbs.org/wgbh/pages/frontline/shows/teenbrain/from/sleep.html#fnB0

3. Jenni OG., Achermann P. and Carskadon MA. Homeostatic sleep regulation in adolescents. SLEEP 28 (2005) 1446-1454.

4. Tobler, Irene and Achermann, Peter, Sleep homeostasis.http://www.scholarpedia.org/article/Sleep_homeostasis

5. What is Sleep, Biological Clock and Homeostasis videos: http://www.videojug.com/interview/healthy-sleep-for-children#what-is-our-bodys-internal-clock

6. Biological clock diagram http://commons.wikimedia.org/wiki/File:Biological_clock_human.PNG.

7. Nova sleep movie: http://www.teachersdomain.org/resource/oer08.sci.life.reg.sleep/