arosca...
First, let's define the sleep stages. According to this
site by the National Sleep Fopundation, there are four:
"You begin your nightly journey by descending into
Stage 1, a light sleep. Your muscles relax, your brain
waves are irregular and rapid. In Stage 2, brain waves
become larger, with bursts of electrical activity.
Then you move into deep sleep, Stages 3 and 4, in which
the brain produces large, slow waves (sometimes called
"delta" or slow-wave sleep). You're more difficult to
awaken in slow-wave sleep."
"After an hour or so, you shift into a highly active
stage characterized by rapid eye movements, hence the
name REM sleep. Suddenly your brain waves are almost
the same as if you were awake. You're in the dreaming
stage, which occurs several times across the course
of the night."
"About 75 percent of your night is spent in non-REM
sleep and about 25 percent dreaming. REM periods tend
to become longer and more plentiful as the night wears
on. Fortunately for your partners and neighbors,
you're essentially paralyzed during REM so that you're
not acting out your dreams no matter how real they may
seem. Occasionally, you may awaken before this
paralysis has entirely ended - Don't be alarmed, it
will pass in a matter of moments."
http://www.sleepfoundation.org/publications/nos.html
Then, there is a specific study which exactly addresses
your question, done by Dr. Vadim S. Rotenberg, a Russian
psychiatrist and psychophysiologist with very impressive
credentials, which can be viewed here:
http://rjews.net/v_rotenberg/book4.html
There are links to several of his sleep studies listed.
The study which pertains to your question is:
====================================================
"THE ESTIMATION OF SLEEP QUALITY IN DIFFERENT STAGES
AND CYCLES OF SLEEP"
SuMMARY
"Dream content in NREM and REM sleep correlates with
the subjective experience of having slept immediately
before awakening. The estimation of depth of sleep
depends on the quality of the NREM sleep stages.
The presence of dreaming in a given sleep stage is
more important for the subjective experience of
having slept than the duration of the sleep episode
before the awakening. Neurotic insomniac patients
more often deny mental activity when awoken from
NREM and REM sleep, than do healthy subjects.
These data suggest that spontaneous awakenings
in different sleep stages, especially in the first
sleep cycle, correlate with the insomniac's
tendency to underestimate sleep duration and quality."
And, specific to your query:
"...estimation of sleep depth was more dependent on
the sleep cycle than on the duration of the preceding
sleep stage. Does this difference depend on the
increase of sleep duration from cycle to cycle, or on
the absence or presence of REM sleep in the segment
of sleep before the awakening? We found that the
estimation of sleep quality did not depend on whether
the sleep duration before the awakening was more or
less than 90 minutes. However, if this sleep included
REM sleep, then the awareness of sleep prevailed.
Sleep periods less than 90 minutes had a different
influence on sleep estimation, depending on the
absence or presence of REM sleep. If REM sleep
occurred in the sleep episode, then reports of deep
sleep appeared more often, and sleep denial was
rare (P < 0.05). If the sleep period exceeded 90
minutes, and excluded REM sleep, then reports of
sleep denial prevailed, but if such sleep periods
included REM sleep, then reports of deep sleep
prevailed."
http://rjews.net/v_rotenberg/quality.html
The study is thoroughly discussed on the same page.
This essentially mirrors what every psychology
student is taught (such as myself), and that is,
that REM sleep is a pre-requisite for the experience
of satisfying sleep. Moreover, the absence of REM
sleep can quickly lead to psychotic symptoms, such
as hallucinations. There have been other studies,
which I cannot quote, in which subjects were allowed
every stage of sleep except REM sleep. Whenever
their eye-movement indicated Rapid Eye Movement,
they were awoken. They reported poor quality of sleep,
and quickly demonstrated a tendency to hallucinate.
Dreaming, then, or REM sleep, is essential for our
psychological well-being, and our experience of
satisyfying sleep. "To sleep, perchance to dream"
should perhaps be "To sleep, and, of necessity, to
dream".
Searches done, via Google:
"sleep stages" "quality of sleep"
://www.google.com/search?hl=en&ie=UTF-8&oe=UTF-8&q=%22sleep+stages%22+%22quality+of+sleep%22
Please do not rate this answer until you are satisfied that the
answer cannot be improved upon by means of a dialog with
the researcher through the "Request for Clarification" process.
sublime1-ga |
Clarification of Answer by
sublime1-ga
on
01 Dec 2002 14:51 PST
arosca...
Dr. Rotenberg's study is based on reports of the
subjects, who are defining "better sleep" as the
experience of having slept deeply, versus having
slept shallowly, or experiencing not having slept
(sleep denial, he calls it). Table 1 shows the
results of the reports of the study.
If you look under reports of "deep sleep", you can
see that his patients (those diagnosed with a
neurotic syndrome) uniformly reported deep sleep
more frequently after being awoken from REM sleep,
no matter how many cycles of sleep they had
experienced, though they also reported deep sleep
more frequently in the first and second cycle,
when awakened from stage 3 or 4 "slow-wave sleep".
You can also see that 'healthy' subjects (Ss)
reported "deep sleep" more frequently, following
being awakened from REM sleep, with the exception
that, after only one cycle, they reported deep
sleep more frequently after being awakened from
stages 3-4 "slow-wave sleep". In subsequent cycles,
the healthy subjects reported deep sleep ONLY after
REM sleep, and with increasing frequency pursuant
to increased numbers of cycles.
The information above would lead me to conclude that
neurotic patients, who often experience insomnia or
troubled sleep, are quicker to report deep sleep
following both slow-wave sleep and REM sleep. In
a sense, they are satisfied more easily at having
slept that deeply. Also note that 5 of the 9 neurotic
subjects who reported deep sleep after one cycle of
slow-wave sleep, also reported having dreams, without
having reached REM sleep!
Healthy subjects, in contrast, report deep sleep less
frequently, and with increasing frequency following
increasing numbers of cycles. In other words, they're
used to a higher quality of sleep, and are increasingly
satisfied as they experience the REM dream state in the
later cycles of sleep (9 of them reported deep sleep
ONLY after the 4th cycle of REM sleep, and none of them
reported deep sleep following any stage, other than REM,
in earlier cycles, with the exception being after
slow-wave sleep in the very first cycle).
I hope that helps. Please feel free to post another
Request for Clarification if I can assist you furhter.
|
Clarification of Answer by
sublime1-ga
on
01 Dec 2002 14:59 PST
arosca...
Dr. Rotenberg's study is based on reports of the
subjects, who are defining "better sleep" as the
experience of having slept deeply, versus having
slept shallowly, or experiencing not having slept
(sleep denial, he calls it). Table 1 shows the
results of the reports of the study.
If you look under reports of "deep sleep", you can
see that his patients (those diagnosed with a
neurotic syndrome) uniformly reported deep sleep
more frequently after being awoken from REM sleep,
no matter how many cycles of sleep they had
experienced, though they also reported deep sleep
more frequently in the first and second cycle,
when awakened from stage 3 or 4 "slow-wave sleep".
You can also see that 'healthy' subjects (Ss)
reported "deep sleep" more frequently, following
being awakened from REM sleep, with the exception
that, after only one cycle, they reported deep
sleep more frequently after being awakened from
stages 3-4 "slow-wave sleep". In subsequent cycles,
the healthy subjects reported deep sleep ONLY after
REM sleep, and with increasing frequency pursuant
to increased numbers of cycles.
The information above would lead me to conclude that
neurotic patients, who often experience insomnia or
troubled sleep, are quicker to report deep sleep
following fewer cycles of both slow-wave sleep and
REM sleep. In a sense, they are satisfied more easily
with having slept that deeply. Also note that 5 of the 9
neurotic subjects who reported deep sleep after one
cycle of slow-wave sleep, also reported having dreams,
without having reached REM sleep!
Healthy subjects, in contrast, report deep sleep less
frequently, and with increasing frequency following
increasing numbers of cycles. In other words, they're
used to a higher quality of sleep, and are increasingly
satisfied as they experience the REM dream state in the
later cycles of sleep (9 of them reported deep sleep
ONLY after the 4th cycle of REM sleep, and none of them
reported deep sleep following any stage, other than REM,
in earlier cycles, with the exception being after
slow-wave sleep in the very first cycle).
The fact that both groups reported deep sleep, to some
extent, following slow-wave sleep in the first cycle,
suggests, to me, that there is a mechanism which
allows us to feel rested if our sleep is prematurely
interrupted, as long as we've made it to the 3-4
stage of the cycle, and experience some slow-wave
sleep. This may be the mechanism which makes
the 'power nap' effective!
I hope that helps. Please feel free to post another
Request for Clarification if I can assist you further.
|
