characteristics and patterns of sleep

1. Lesson 3: Characteristics and Patterns of Sleep

2. Exam Question:
Ella loves Yoga. She finds it relaxing and it helps her to
deal with the stressful activities of her day.
a) What brainwave pattern would Ella show during a Yoga
session? Explain your response.
b) Which device would best measure Ella’s brainwave
pattern? Explain your response.
Hint: her brainwaves
look similar to this ~>

3. Model Response
a) Alfa waves because Ella is in a meditative state,
awake but very relaxed, which is associated with
reasonably high frequency (but not as high as beta
waves) and low amplitude (but slightly higher than
beta waves) brainwaves.
b) An Electroencephalograph (EEG) because it
detects, amplifies and records electrical activity in
the brain in the form of brainwaves.

4. http://www.youtube.com/watch?v=t27suXgfi8w

5. Characteristics of Sleep

6. NREM Sleep Non-rapid eye movement sleepNREM sleep includes those stages not associated with rapid eye
movements. Adults spend approximately 80 percent of their nights
sleep in NREM, and typically the first half of the night has more
NREM sleep than the second half.
NREM is essential to the physical growth and repair of the body.
Research has found the amount of NREM increases after vigorous
exercise (Vein et al., 1991).
NREM is dream free about 90% of the time, dreams tend to be more
short lived and fragmented than those in REM.

7. NREM Stage 1
~Theta waves, which are of lower frequency and higher amplitude than
alpha waves, appear and start to replace alpha waves.
~Despite the fact that various wave types are shown in this stage, theta
waves define Stage 1 NREM sleep.
~In stage one of sleep, breathing becomes irregular, muscles relax, and
hypnic jerks often occur.
~Stage 1 lasts for approximately 2 min.

8. NREM Stage 2
~In this stage there is a prevalence of theta-wave activity.
~ As sleep deepens EEG recordings begin to pick up unique brain wave
features that are characteristic of stage 2 sleep. Theses include
• Sleep spindles – brief bursts of higher frequency brain waves
• K complexes – single sharp bursts (rise then fall) in amplitude (and
lower frequency).
• Body temperature decreases
~Stage 2 sleep lasts for approximately 20 min

9. NREM Stage 3
~Delta waves begin to appear which are
large and slow.
~Stage 3 is a transitional stage and lasts
for approximately 2 min.

10. NREM Stage 4
~Brain waves become almost pure delta waves
~Regular (slow) heartbeat, slow (rhythmic) respiration &
little muscle activity
~Possible occurrence of night terrors
~Very hard to awaken a sleeper from Stage 4 sleep.

11. REM ~ Rapid Eye Movement
~REM sleep is strongly associated with dreaming. About 85% of the time
a person is awakened from REM sleep they report vivid dreams.
~On average REM sleep totals about 90 min per night. The amount of
REM sleep tends increases with stress in an individuals life.
~REM sleep is sometimes called paradoxical sleep, as aspects of REM
sleep appear to contradict each other. The brain wave pattern is very
much like those produced during alert wakefulness. The bodies internal
functioning is more active during REM sleep than during NREM sleep, the
heart beats faster, breathing is more rapid and irregular, and genitals
become aroused. On the other hand, the sleeper is totally relaxed; most
of the skeletal muscles are totally relaxed (to the point of paralysis).

12. Patterns of SleepAn adult sleeps for approximately 8 hrs per night progressing through cycles of about 1.5 hours. Periods
of deep sleep (NREM4) occur earlier in the night, and periods of REM sleep occur, on average every 90
minutes.
Adults experience a total of 1-2 hours REM sleep a night, in 4-5 sessions, each progressing in length.
The period of total REM sleep lessons as individuals get older. A newborn spends approximately 50% of
total time in REM sleep compared to an adult who spends approximately 20% of their time in REM sleep.

13. WHY DO WE SLEEP?

14. Survival Theories
Focuses on when and why different species sleep
Sleep depends on the need to find food
Sleep depends on an animal’s vulnerability to predators
Sleep conserves energy

15. Limitations of Survival Theories
Survival theories state that sleeping offers security
from predators, however the loss of awareness
while asleep contradicts this statement.
Survival theories fail to explain why we MUST sleep

16. Restorative Theories
Focuses on why sleep is important
Sleep enhances mood
Sleep repairs and replenishes the body
and prepares it for action the next day
The neurotransmitters adenosine
(energy), norepinephrine (alertness)
Metabolism
Growth hormones
Immunity to disease
Consolidates memories

17. Limitations of Restorative Theories
The body does not completely “rest” during sleep
(REM) as assumed by restorative theories
Lack of physical activity does not reduce the
amount of sleep needed