THIS PRESENTATION IS ABOUT THE VARIOUS COMPONENTS OF SLEEP CYCLE

1. Sleep Cycle
Dr. Gurpreet Singh, Ph.D [Biotech.]
Assistant Professor
P.G. Department of Biotechnology
Lyallpur Khalsa College, Jalandhar (INDIA)

2. 24 Hour body cycle

3. Sleep is defined as
“a natural and periodic state of rest
during which consciousness of the world
is suspended.”
The study of sleep began in the 1920s
when the encephalogram (EEG) was
invented which enabled scientists to read
brain waves.

4. Why Sleep?
Repair and Restoration Theory
– sleep enables the body and brain to repair
itself after working hard all day
– going without sleep causes people to be
irritable, dizzy, and to have hallucinations
and impaired concentration
– sleep-deprived rats’ bodies work harder
– BUT, how much we sleep does not depend
on how much we worked that day

5. When we are awake we are?
In a state of Consciousness
Our awareness of ourselves
and our surroundings.

6. CATAGORIES OF SLEEP
• There are two main categories of
sleep:
• Non-Rapid Eye Movement (NREM)
sleep, which restores the body,
• Rapid Eye Movement (REM) sleep
which restores the mind.

7. Stages of sleep
NREM
REM

8. Sleep Stages
• It takes about 90-100 minutes
to pass through the 5 stages.
• The brain’s waves will change
according to the sleep stage
you are in.

9. Stage One
• experienced as falling to sleep and is a
transition stage between wake and sleep.
• usually lasts between 1 and 5 minutes and
occupies approximately 2-5 % of a normal
night of sleep.
• eyes begin to roll slightly.

10. Stage Two
• This follows Stage 1 sleep and is
the "baseline" of sleep.
• This stage is part of the 90 minute
cycle and occupies approximately
45-60% of sleep.
• Respiration declines,
• slowing of pulse and temperature.

11. Stage Three & Four
• Stages three and four are "slow wave" sleep and
may last 15-30 minutes.
• It is called "slow wave" sleep because brain
activity slows down dramatically from the Stage 2
to a much slower rhythm

12. Stage Three and Four (contd)
• It is the "deepest" stage of sleep (not REM) and
the most restorative. Production of growth
hormones.
• In children, delta sleep can occupy up to 40% of
all sleep time and this is what makes children
unawake able or "dead asleep" during most of
the night.

13. Stage Five: REM SLEEP
• REM: Rapid Eye Movement
• This is a very active stage of sleep.
• Composes 20-25 % of a normal nights
sleep.
• Breathing, heart rate and brain wave
activity quicken.
• Muscles are so relaxed they are
paralyzed
• Vivid Dreams can occur.
• From REM, you go back to Stage 2

14. Animal Sleep
• Animals, like humans
also have a required
certain amount of
sleep:
SPECIES
Average total sleep
time per day
Python 18 hours
Tiger 15.8 hours
Cat 12.1 hours
Chimpanzee 9.7 hours
Sheep 3.8 hours
African Elephant 3.3 hours
Giraffe 1.9 hours

15.  Sleep disorders affect the quality, duration, and
onset of sleep.
 Sleep deprivation, frequently changing sleep
schedules, stress, and environment all affect
the progression of a sleep cycle.
 Psychological conditions like depression
shorten the duration of REM.
 Treatment and medication often affects sleep,
typically causing a change in sleep habits.
Factors Affecting Cycle and Stages of Sleep

16. Sleep well and lead
a healthy life!!!!!!!!