martedì 5 febbraio 2008

The importance of the sleep cycle

It is good to understand the dream process. To do that, we need to look at the mind. Where does dream come from? How does it come about? Does it have any relation to sleep cycles? These questions and more we will answer as we move along.


There are four stages in a sleep cycle. Each cycle will play itself out after the other. In short, stage 1 is stage 1 and stage 2 is stage 2 and so on and so forth. The time that each cycle takes to play itself out is entirely random. There are no benchmarks or fixed times for the length of sleep stages.

The four stages of sleep are as follows:

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.

 

The dreams that are most likely to be remembered are those that take place 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.

 

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