Sleep Stages

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Sleep Stages

• Professor Ken Daley
• Department of Exercise and Sport Science

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Two Major Types of Sleep

• Non-REM (non-rapid eye movement)
• REM (rapid eye movement)

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Transition From Waking State

• beta waves to alpha waves
• eyes moving spontaneously in a slow rolling eye
  movement.
• Their heart and respiratory rates vary depending
  on the individual.
• The individual has spontaneous movements (i.e.
  changing positions to become comfortable).

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Alpha Rhythm and Slow Rolling Eye Movement
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Non-REM (rapid eye movement)

• most of the muscles relax, body systems take a
  rest, and the brain waves associated with
  wakefuleness and alertness disappear and are
  replaced by increasingly slow, deep waves of
  inactivity.
• accounts for 70 of the total sleep time of a
  young adult

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4 stages of NREM sleep

• STAGE 1
• takes 5-10 minutes
• less aware of their surroundings
• May waken by a whisper, or noise.
• Are relaxed, breathing is more regular and there
  is more slow, rolling eye movement noticed.
• May have "hypnogogic expriences" - dream-like
  sensations of falling, hearing voices, or seeing
  flashes of pictures.

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• STAGE 2
• first stage of true sleep
• 50 of total sleep
• Stages 12 lasts about 30 minutes
• Sleep spindles and K-complexes characterize this
  sleep stage.

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Sleep Spindles
K-Complexes
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• STAGE 3 and 4
• very relaxed state with a slow, regular heartbeat
  and respiratory rate.
• Their muscles are very relaxed.
• It is very difficult to arouse a patient in Slow
  Wave Sleep.
• If awakened, you are confused and slow to react.
• It is normally easy to go back to sleep.

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Delta Waves
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• Growth hormone is secreted. This hormone in
  children encourages growth.
• The body is believed to carry out most of its
  repair work.
• A healthy young adult spends about 7 sleep time
  in stage 3 and 11 in stage 4

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REM (rapid eye movement)

• eyes move in a rapid, flickering, twitching
  motion while their eyelids are closed.
• The EMG leads are still as the patient is
  temporarily paralyzed during this stage. This
  temporary paralysis includes the respiratory
  muscles, except for the diaphragm.

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• It is suggested that this paralysis is a clever
  device that lets the mind explore the realms of
  its subconscious, while preventing us from acting
  out dream events.
• Blood flow to the brain is increased during this
  stage of sleep. In children, may help enable the
  brain to grow and in adults to repair itself.

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• Healthy young adults first experience REM sleep
  within 90 minutes of sleep of falling asleep.
• It recurs about every 90 minutes throughout the
  night and each time it recurs, we spend a little
  bit longer in this stage.

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The EEG waveforms include sawtooth waves and
waveforms that have sharp rapid "deflections"
(hence the term, Rapid Eye Movements).
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Have a good sleep
But Not In Class
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Source
http//www.silentpartners.org/sleep/sinfo/s101/phy
sio4.htm