The importance of the sleep cycle
It is important to understand the sleep cycle in order to
understand the dreaming process. Before we can gather
information from our dreams, we need to understand where those
dreams come from, and to do that we must understand the various
stages of sleep and how they fit together. The sleep cycle
consists of four individual stages, and every person goes
through all four stages each and every night. The length of each
cycle varies from person to person, but every human being
experiences all four stages of sleep every night. In general,
the dreams that are most likely to be remembered are those that
take place the closest to waking. Dreams that take place earlier
in the night are almost never remembered. The one exception to
this rule is those dreams that are disturbing enough to wake the
dreamer. If a dreamer awakens in the middle of dream sleep, as
with a particularly vivid nightmare or a dream about falling, he
or she will most likely remember vividly every detail of the
dream. Let us take a look at the four individual stages of
sleep, starting, logically, at stage one. Stage 1: The initial
stage of sleep is a very light sleep, and the slightest
disturbance can wake the dreamer at this stage. The first stage
of sleep usually lasts for only a few minutes, and most sleepers
move on quickly to stage two.
Stage 2: The second stage of sleep is much deeper, and it is
much harder to wake the sleeper up at this point. While the
dream state begins in stage two, there are usually no clearly
formed images at this point. Instead dreams in stage two consist
mainly of vague ideas and images floating around the mind. After
stage two is completed, the dreamer moves quickly on to stage
three.
Stage 3: The third stage of sleep is even deeper than the second
stage. At this stage, the muscles in the sleepers body have
relaxed, and the heart rate and respiration rate have both
slowed down. The sleeper's blood pressure also drops off at this
point, and breathing is typically even and steady. A sleeper in
stage three sleep is very difficult to awaken, and typically
waking can only be accomplished by a very loud startling noise
or by shouting the sleeper's name repeatedly.
Stage 4: Stage four is the deepest stage of sleep, and the one
in which most dreaming takes place. During this stage of sleep,
it is almost impossible to wake the sleeper. During stage four
of sleep, the sleeper moves in and out of REM (rapid eye
movement) sleep several times. It is during REM sleep that
dreaming is occurring. The eyes move back and forth rapidly
under their lids, the heart beat and respiration spike, and
brain wave activities increase. As a matter of fact, studies
have shown that brain wave activity is higher during dream sleep
than it is during normal consciousness.
Most sessions of dream sleep last for about 10 minutes, after
which the sleeper returns to the normal deep sleep of stage
four. The dreamer will cycle back and forth between stage four
sleep and dream sleep several times each night, usually
repeating the process from four to seven times on an average
night.