• We sleep in cycles

• Each sleep cycle involves transitions between four different stages of sleep

  • NREM (Non-Rapid Eye Movement) 1, 2, and 3

  • REM (Rapid Eye Movement)

• Each stage involves different psychological and physical changes

• Throughout the night we go through cycles approximately every 90-120 minutes

The Process

• As we sleep, we transition to ‘deeper’ stages that are more internally active

• NREM-3 gets shorter with every cycle

• REM gets longer with every cycle

• NREM-1 → NREM-2 → NREM-3 → NREM-2 → REM

NREM-1

• 5-10 minutes

• Light sleep

• When in this stage, you may feel like you’re floating, falling, or tingling

• Alpha waves

NREM-2

• Stable transitional stage

• 10-20 minutes

• Harder to awaken

• Theta waves

NREM-3

• Deepest sleep

• Hardest to awaken

• Delta waves

• Gets shorter throughout the night

• The growth hormone is released during this phase

• In this phase, the ‘body sleeps’

  • All NREM’s, to an extent, are sleep for the body

  • Sleepwalking and talking in one’s sleep also all occur in the NREM stages

REM

• Rapid Eye Movement

• Beta waves

• Very internally active

• Externally paralyzed

• Dreams and nightmares occur in this phase

• Memory synthesis

• REM is like ‘sleep for the mind’

Sleep Theories

• We spend roughly 1/3 of our lives asleep, but why?

Restoration Theory

• Our bodies wear out during the day and use up resources

• Sleep is necessary to restore these resources and reenergize the body

  • Sleep helps restore and repair muscles and brain tissue

  • Sleep supports growth

Adaptive Theory

• Based on evolutionary approach

• Sleep protects us

• Sleep emerged first in animals who evolved to preserve energy

  • It protects us during times where movement is not valuable and removes us from considerable danger

• Sleep helped animals adapt to their environments, helping them survive, meaning the trait/behavior was passed down

Cognitive and Information Processing Theories

• Sleep helps us restore and rebuild our memories of the day’s experiences

  • Memory consolidation occurs during REM

• Sleep deprives individuals struggle cognitively

  • REM deprivation studies show this

• People from all ages remember prior day’s events better with a well-rested brain

  • Even rats remember how to get through a maze they learned the day before better when having slept well

Psychological Theory

• Originated with psychoanalyst Sigmund Freud

  • He published “The Interpretation of Dreams” in 1900 on the subject

• Proposed that dreams are the road to the unconscious mind

  • They’re filled with content we cannot face in conscious, waking life

• Manifest and Latent content

  • The literal content of the dream and the implied meaning of it

• Many modern psychological theories are similar to Freud’s original theory

Biological and Information Processing Theories

• Dreams provide a way to sort out the day’s events and consolidate our memories for storage

• Activation-Synthesis Model

  • REM helps preserve and develop neural connections

  • REM triggers neural activity in the cortex as memories are synthesized

  • Activation leads to synthesis

Sleep Disorders

• We know that sleep restores, protects, rejuvenates, and helps us perform

• But millions of people are sleep deprived, even knowing its value

Insomnia

• The inability to fall or stay asleep, or both

• Insomnia is the most common of all sleep disorders

• Insomnia derives us not only of sleep, but of the many cognitive and physical benefits that sleep provides

Causes

• Stress

• Irregular sleep schedule

• Pain/illness

• Diet/medications

Treatment

• Depends on the cause

• Stress management

• Medications/melatonin

• Treatment of pain/illness

• Changing habits

Sleep Apnea

• Cessation of breathing while sleeping

• Breathing stops repeatedly throughout the night

• Snoring, gasping

• Never feeling rested and restored even after a full night of sleep

• There are three types

  • Obstructive

  • Central (CNS)

  • Complex

Causes

• Risk factors include…

• Weight

• Smoking

• Gender

• Age

• A thick neck

• A narrow airway

• Nasal obstruction

Treatment

• Depends on the cause and type

• Losing weight

• A C-PAP machine

Narcolepsy

• Falling into uncontrollable, deep sleep all throughout the day

• Drowsiness

• Muscles paralysis (cataplexy)

• Immediately falling into REM sleep

Causes

• Genetic

• Damage to the reticular formation

Treatment

• Medication

• Support/accommodations