The Sleep Cycle
Unit 3
Lesson 2
Objectives:
• Define sleep
• Identify the main theories of sleep
• Differentiate between the stages of sleep
Warm Up
• Describe two of the
five different levels of
consciousness we
talked about
yesterday.
What Is Sleep?
• An altered state in
which people become
relatively unaware of
external stimulation
Studying Sleep
• (1953) EEG records
brain wave activity
– Frequency and
strength
• EOG record eye
•
•
movements
EMG record muscle
movements
EKG records activity of
the heart
Online Activity
• Use PsychSim 5.0 “EEG & Sleep Stages” at
http://www.worthpublishers.com/exploring5
e/content/psychsim5/EEG%20and%20Sle
ep%20Stages/PsychSim_Shell.html
EEG and Sleep Stages
• Awake = Beta Waves
• Stage 1 = Theta Waves
– Hypnagogic State
• Stage 2 = Theta Waves
– Sleep Spindles
• Stage 3 = Delta Waves
• Stage 4 = Delta Waves
– Bedwetting, Sleep talk/walk
– Night Terrors
• REM = Mimic’s Beta Waves
– Atonia, DREAMING!
Sleep Cycle
• Roughly 5 periods of
REM sleep per night
– Sleep becomes
lighter as night
wears on
– REM sleep
becomes longer
towards am
Why Do We Sleep?
• Evolutionary Theory: Protective function, keeps people
tucking away at night, safe from predators.
• Recuperative Theory: Conserves energy, restores body
tissues depleted during daily activity
– REM: hormones released that influence thinking &
memory formation, mental organization; counteract
fatigue, irritability, inattention
– NREM: body replenishes itself (tissue restoration and
release of growth hormone)
Why Do We Sleep At Night?
• Circadian Rhythm
– Internally generated
sleep/wake cycle
connected to 24-hour
pd of earth’s rotation
How Much Sleep Do I Need?
• Infants
– 20 hours
• 50% REM
• Children/Adolescents
– 10 hours
• 25-30% REM
– Bed Later, Up Later
• Adults
– 8 hours
• 20% or less REM
• Elderly
– 6 hours
– Bed Later, Up Earlier
What If I Miss Sleep?
• Effects On Body
– Immune system
weakens
– Metabolic malfunction
– Varied body temp
• Effects On Brain
– Moodiness
– Decreased cognitive
performance
• Learn slower,
remember less, loss
concentration &
creativity
– Blurred vision
– Disorganized speech
– Hallucinations
Sleep Activities
• Am I Sleep Deprived?
• Sleep Myths Quiz
Am I Sleep Deprived? Yes/No
•
•
•
•
•
•
I need an alarm clock to wake
up for school.
It’s a struggle to get out of
bed in the morning.
I hit the snooze bar several
times to get more sleep.
I feel tired, irritable and
stressed out during the week.
I have trouble concentrating
and remembering.
I feel slow with critical
thinking, problem solving and
being creative.
•
•
•
•
•
•
I often fall asleep in boring
classes or warm rooms.
I often fall asleep within 5
minutes of getting into bed.
I often feel drowsy while
driving.
I often sleep extra hours on
weekend mornings.
I often need a nap when I
get home from school.
I have pink circles around or
dark circles under my eyes.
Am I Sleep Deprived? Yes/No
• An answer of “yes” to
three or more of the
previous questions
indicates sleep
deprivation.
• You can easily improve
your mood, performance
and health by getting
more sleep!
Closure
• How has sleep deprivation affected your
life? Which activities contribute most to
your sleep deprivation?