I. Sleep

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I. Sleep

• Why do we sleep?

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• A natural state of rest characterized by a
  reduction voluntary movement and decreased
  awareness of the surrounding.
• Human beings spend approximately 1/3 of their
  lives sleeping
• When sleep deprived people crave sleep just as
  strongly as they crave food or water

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• Nobody exactly knows why we need to sleep.
• Evolutionary psychologists see sleep as an
  adaptive mechanism that evolved to allow
  organisms to conserve and restore energy.
• Researchers have shown that people use less
  energy when they are sleep than when they are
  awake.
• Protein synthesis
• Chemical adenosine is elevated when sleep deprived

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Most of us Need More Sleep

• Lack of sleep is a national epidemic
• 1/3 to ½ of adults regularly fail to get enough
  sleep
• 1950s 8-12 hours of sleep/avg
• 1990s less than 7
• 2002 6.9 hrs/night during the work week and 7.5
  on the weekend
• High School and college students receive less
  than 6 hours per night.
• 30 of students report sleeping during class

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• Losing an hour or two night after night, week
  after week, month after month makes it more
  difficult to pay attention in class
• Especially monotonous tasks
• Reaction times slow down, behavior becomes
  unpredictable, logical reasoning is impaired, and
  productivity and the ability to make decisions
  decline

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Effects

• 200,000-400,000 automobile accidents
• Resulting in 1,500 deaths
• Just as dangerous as driving drunk
• Other short-term consequences include
• Decreased daytime alertness. Loss of just one and
  half hours sleep can result in a 32 reduction in
  daytime alertness.
• Impaired memory and cognitive ability, the
  ability to think and process information.
• More than double the risk of sustaining an
  occupational injury.
• Impaired immune system.

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Long Term Effects

• One well-known study undertaken more than a
  decade ago showed that a rat prevented from
  sleeping will
• die in about three weeks, having lost the
  ability to maintain body heat and develop a fever
  to stave off infection.
• In humans, fatal familial insomnia, a
  degenerative brain disease, leads to death after
  several months, though scientists have not
  determined whether the cause of death is the
  sleep loss or other aspects of brain damage.
  While this disease is extremely rare, lack of
  sleep can have dramatic effects on quality of
  life.

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Other Long Term Effects

• High blood pressure
• Heart attack
• Heart failure
• Stroke
• Psychiatric problems such as depression and other
  mood disorders
• Mental impairment
• Increased mortality risk
• Relationship problems with a bed partner
• Obesity - (The link between obesity and sleep is
  an interesting one as lack of sleep can cause
  weight gain by increasing hunger and affecting
  metabolism, and extra weight can cause sleep
  disorders such as apnea which cause sleep
  deprivation.)

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Exxon Valdez

• http//www.youtube.com/watch?vG1U-iWUPOYA

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II. Circadian Rhythm

• From the Latin circa diem about a day
• Are an ancient and fundamental adaptation to the
  24 hour solar cycle of light and dark found in
  all living creatures
• Suprachiasmatic Nucleus (SCN) Biological clock
• A tiny cluster of neurons in the lower region of
  the hypothalamus
• Receives information about the daily light and
  dark cycles directly from the eye by way of a
  specifically dedicated neuropathway originating
  in the retina

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• SCN secretes specific neurotransmitters to
  regions of the brain like the reticular formation
  and hypothalamus that in turn control our bodys
  temperature, metabolism, blood pressure, hormone
  levels and hunger.
• Epinephrine which causes the body to go on
  alert reaches peak levels in the late morning
  hours and then steadily declines until around
  midnight, where it drops to very low levels until
  the morning
• Melatonin Promotes sleepiness surge at night
  and drops off during the day
• Even in misleading environment the SCN is self
  regulating
• SCN resets itself to match the prevailing cycles
  of light and dark

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• Hypothalamus does not distinguish between real
  and artificial light
• Exposure to bright light after dark suppresses
  our natural response to changes in the light
  cycles
• Effects levels of melatonin
• Melatonin in the morning can be enough to slow
  down the biological clock
• Melatonin at night speeds up the biological clock
  making a person fall asleep earlier

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Desynchronization

• Disruptions in the circadian rhythm
• Jet Lag
• Sleep and wake cycles adapt quickly but hormones,
  body temperature, and digestive cycles change
  more slowly
• Body functions are out of synch
• Affects shift workers

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III. Rhythms of Sleep

• Twilight Brain wave patters are characterized
  by irregular, low voltage alpha waves.
• Mirrors our brain when we are relaxing lying on a
  beach

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Stage 1 Sleep

• Stage 1 brain wave patterns are tight and of very
  low amplitude (height)
• Slowing of heart rate, muscle relaxation, and
  side-to-side rolling movements
• Stage 1 usually lasts for a few moments

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Stage 2 Sleep

• Progressively deeper sleep
• Appearance of sleep spindles
• Short rhythmic bursts of activity periodically
  appear

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Stage 3

• Stage 3 delta waves slow waves with very high
  peaks begin to emerge
• During these stages, the sleeper is hard to
  awaken and does not respond to stimuli such as
  noises or lights
• Heart rate, blood pressure, and temperature
  continues to drop

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Stage 4

• Stage 4 The brain emits very slow delta waves
• Heart rate, blood pressure, and body temperature
  are as low as they will get during the night
• Delta sleep occurs in 15-20 minutes segments
  interspersed with lighter sleep mostly during
  the first half of the night.
• Delta sleeps time lessens with age but continues
  to be the first sleep to made up after sleep has
  been lost

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Sleep Cycle

• About an hour after falling asleep the sleeper
  begins to begins to ascend from stage 4 sleep
• To stage 3 sleep
• To Stage 2 sleep
• Back down to Stage 1 sleep
• A 40 minute process

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Stage 5 - REM

• Brain waves return to a low amplitude, saw
  toothed shape characteristic of stage 1 sleep or
  waking alertness
• Heart rate, blood pressure also increase
• Yet the muscle are more relaxed then at any point
  in the night
• Person is very difficult to awaken
• The eyes move rapidly under closed eyelids
• Different then NREM (stage 1-4)

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• Paradoxical sleep
• Voluntary muscles are paralyzed
• Dreaming takes place during this stage
• Beginning of the night REM sleep only lasts for a
  few minutes
• 1st half of the night stages 3-4 dominate
• 2nd half of the night REM sleep is longer
• 50 of the time is spent in stage 2
• 25 of the time is spent in REM stage

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Stages of Sleep
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Sleep Chart
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Sleep Cycles
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• http//www.pbs.org/wgbh/pages/frontline/video/flv/
  generic.html?sfrol02sfacq392continuous1

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III. Sleep Disorders

• Sleepwalking, Sleep Talking, Night Terrors
• Insomnia
• Apnea
• Narcolepsy

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Sleep Walking, Talking, and Night Terror

• Occur during stage 4 sleep
• Most common in children rather than adults
• 20 of children have had at least one episode of
  sleep walking or sleep talking
• Boys are more likely to walk then girls
• Waking a sleep walker is not dangerous
• Just hard

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Night Terrors/Sleep Paralysis

• During REM stage people dream, and extensive
  physiological changes occur
• such as increased brain activity, accelerated
  respiration, eye movement, and muscle relaxation.
  In order to keep us from acting out our dreams
  our bodies secrete hormones that paralyze us.
•  During most regular sleep cycles the hormones
  begin to wear off even before the dream is
  completed, thats why people wake up with a
  perfectly functioning body.
•  However, sometimes an individual awakens before
  the hormones  become inactive.
• They are completely paralyzed

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• On occasion, immediately after the person is
  awake, they are startled by a terrifying visual
  hallucination.
• Sometimes this hallucination takes on a
  stereotypical form.
• It is usually a vision of a creature sitting on
  their chest and possibly choking them. 
• Some people say that Alien Abduction victims are
  nothing more than Sleep Paralysis victims.

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• Many adults who have sleep terrors are also
  likely to have a history of one of the following
• Bipolar Disorder
• Some depressive disorders
• Anxiety Disorders

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Insomnia

• In ability to fall or remain asleep
• Afflicts as many as 35 million Americans
• Insomnia generally grows out of stressful and
  temporary events
• For some insomnia is a part of a larger
  psychological problem such as depression
• Interpersonal difficulties such as loneliness
• Aroused biological system
• Physical predisposition may combine with distress
  thus reinforcing each other
• Bad sleeping habits

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Apnea

• Breathing or snoring difficulties
• Inherited
• 10-12 million Americans suffer from it
• Victim may stop breathing during sleep
• As carbon dioxide builds up in the blood Apnea
  sufferers are spurred to a state of arousal just
  short of waking consciousness
• Hundreds of times per night
• Exhaustion, fall repeatedly during the day,
  depressed, sexual dysfunction, difficulty
  concentrating, headaches
• In children hyperactivity and aggressiveness

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Narcolepsy

• Hereditary Disorder
• Victims nod off without warning
• Experience a loss of muscle tone when they
  express any type of emotion
• A joke, anger, sexual stimulation bring on muscle
  paralysis
• Immediate entry into REM which can bring on
  nightmares or hallucinations (dreams while they
  are partly awake)