Complete Sleep Cycle Stages
It takes 70-90 minutes to move through
the 5 stages of the sleep cycle. An average adult will experience
4-6 full cycles every night. At the end of each cycle, we almost
awake fully before beginning the 5-stage cycle again.
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 Adults spend 4-5% of sleep time in
Light Sleep. Drifting in and out. Very slow
eye/muscle activity. If awakened brain may remember
images or feel the sensation of falling. |
 Adults spend 44-55% of sleep time
in Restorative Sleep. Breathing and heart rate slow.
Very little brain activity. No muscle or eye activity.
Slight drop in body temperature. |
 Adults spend 4-6% of sleep time in
Deep Sleep. No muscle or eye activity. Brain
activity is very slow. The most restorative stage of
the cycle. |
 Adults spend 12-15% of sleep time
in Very Deep Sleep. Stage is also restorative.
No muscle or eye activity. Rhythmic breathing.
If awakened, you feel groggy or disoriented. Body
breaks down proteins and produces more cells. |
 Adults spend 20-25% of sleep in REM
Sleep. "Rapid Eye Movement." Muscles relax,
heart rate increases. Breathing is rapid and slow.
Brainwaves speed up and are similar to waking hours.
Stage where dreams occur. |
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Dreaming has beneficial and necessary effect.
Research has led to the theory that we integrate what we learned
during the day with what we already know, while we sleep.
In the 1950's, experiments were done that involved waking people
when they entered REM sleep. Otherwise, they were allowed
to sleep as much as they wanted. The next night, their
number of REM periods increased, as if to make up for the lost
time. They became irritable, less coherent in speech and
slower in reaction time. Those who were deprived of REM
sleep, but otherwise allowed to sleep, closely resembled those
who were overall sleep deprived. After several days of
deprivation, both sets of deprived subjects started
hallucinating. In essence, they started to dream while
awake. Dreaming is possibly the most important part of
sleep.
DID YOU KNOW...?
A new five-year study found that getting more sleep can reduce
calcium deposits found in the arteries. Specifically,
those who get one extra hour of sleep at night were less likely
to have artery-stiffening calcium deposits. |
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SNOOZE or LOSE!
Sleep stages 3, 4 and 5 are the most
important. Scientists studied the health of sleep-deprived
rats to determine the effect of insomnia on humans. They
found that when deprived of REM sleep, rats that normally live
two years, died in five weeks. When deprived of all
sleep, they died in just three weeks. |
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