2. What we will cover
What is sleep?
Stages of sleep
Why do we sleep?
Effects of sleep deprivation
Video clip on sleep deprivation
Sleep Variations
Conclusion
Questions
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3. What is sleep?
Sleep is a naturally recurring state characterized by
reduced or absent consciousness, relatively suspended
sensory activity, and inactivity of nearly all voluntary
muscles.
OR
It is a natural and periodic state of rest during which
consciousness of the world is suspended.
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4. Stages of sleep
Each and every night, your brain passes through five
stages of sleep. Passing through all these stages takes
about 90-110 minutes and marks one full sleep cycle.
So, if you sleep soundly for eight hours per night,
you're getting five full sleep cycles.
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5. Stages of sleep
Stage 1 is a light sleep and you are easily woken. This
stage lasts about five minutes. Your eyes move slowly
under the eyelids, muscle activity slows down, and you are
easily awakened.
Stage 2 is marked by a loss of nearly all muscle. This is the
first stage of true sleep, lasting from 10 to 25 minutes. Your
eye movement stops, heart rate slows, and body
temperature decreases.
Stage 3 is the beginning of a deep sleep, also known as
Slow Wave Sleep. It is harder to rouse someone from a
deep sleep, but if you are woken you will feel especially
dopey and confused for a couple of minutes.
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6. Stages of sleep (Cont.)
Stage 4 is the deepest kind of Slow Wave Sleep. This stage
replenishes your energy both physically and mentally, and
without enough deep . In this deepest stage of sleep, your
brain waves are extremely slow. Blood flow is directed
away from your brain and towards your muscles, restoring
physical energy.
REM Sleep marks the onset of dreaming. About 70 to 90
minutes after falling asleep, you enter REM sleep, where
dreaming occurs. Your eyes move rapidly, your breathing
shallows, and your heart rate and blood pressure increase.
Also during this stage, your arm and leg muscles are
paralyzed.
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7. Why do we sleep?
Sleep Theory #1 - To Rest : to gain relief from this hyperactive state.
Sleep Theory #2 - To Heal : Sleep also allows us to heal our bodies.
the immune system (our ability to fight disease) sleep deprivation
affects our metabolism (our internal chemical reactions). It may also
help us save energy for when we most need it.
Sleep Theory #3 - To Learn : Sleep may help the human brain get
better organized - by filing away important memories and discarding
unwanted information.
Sleep Theory #4 - To Dream : Dreaming appears to be a by-product
of REM sleep. So is it possible that the main reason why we sleep is to
dream? If so, why do we dream?
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8. Effects of sleep deprivation
Fatigue, lethargy, and lack of motivation
Moodiness and irritability
Reduced creativity and problem-solving skills
Inability to cope with stress
Reduced immunity; frequent colds and infections
Concentration and memory problems
Weight gain
Impaired motor skills and increased risk of accidents
Difficulty making decisions
Increased risk of diabetes, heart disease, and other health problems
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9. Video Clip
A Video on sleep deprivation showing the
negative effects it has on the brain
(http://www.youtube.com/watch?v=f5E4isZdx8k)
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10. Sleep Variation
Sleep is a natural state of rest seen in mammals, birds,
reptiles, amphibians and fish. There is variation of sleep
between animals:
Bats........................20 hours
Lions......................13.5 hours
Laboratory rats......13 hours
Domestics cats.......12.5 hours
Baboons.................9.5 hours
Humans..................8 hours
Pilot whales............5.5 hours
Asian elephants......3 hours
Roe deer.................3 hours
Giraffes...................2 hours
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11. Conclusion
Lack of sleep is stressful and has an impact on the body
and the brain. When deprived of sleep people have trouble
paying attention to task and solving problems.
Sleep is not exactly a time when your body and brain shut
off. While you rest, your brain stays busy, overseeing a
wide variety of biological maintenance that keeps your
body running in top condition, preparing you for the day
ahead. Without enough hours of restorative sleep, you
won’t be able to work, learn, create, and communicate at a
level even close to your true potential.
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