Although we think that our body simply shut down and completely relax during sleep, in fact, many parts of the body remain surprisingly active. This is particularly true for the brain sends a constant stream of signals controlling what is known as our sleep cycle.
There are five stages to a normal sleep cycle and on a good sleep, you experience all five of them several times in a row. The five stages of sleep are roughly divided into two groups. The first group comprised of the first four phases, is known as non-rapid eye movement or NREM sleep, while the second group, only one phase, is intended as a quick eye movement or REM sleep.
The most important difference between NREM and REM sleep is seen in terms of brain activity. In addition, REM sleep is characterized by irregular, but rapid breathing and heartbeat, a rise in blood pressure and almost no muscle activity.
In a normal sleep through the various stages of sleep several times, but tend to spend about the first third of the NREM sleep phases and the last third of sleep in a REM phase.
Stage 1 is the phase where you fall asleep and sees you are drowsy and drifting in and out of sleep. Eye movements begin to slow during the first stage 1 and you start to lose control over your muscles. It is also quite normal at this stage to a sudden contraction of muscles and twitching.
About half of all sleep is stage 2 sleep, in which your activity of the brain and heart rate slows, your temperature and eye contact movement is reduced to virtually none, although there may be occasional short eye movement.
Both stages 3 and 4 are very similar and, together, are considered deep sleep. Brain waves during these two phases are very slow, and there is no movement in either the eyes or the muscles.
REM sleep is interrupted during the other phases of sleep, not necessarily follow a strict numerical order and, overall, about one fourth of the time in idle. The first period of REM sleep, for example, follows Phase 1 and lasts only about ten minutes, during the last period of REM sleep from which you normally awaken, lasts about one hour.
This repetition of sleep stages gives rise to sleep cycles and a normal sleep consists of several cycles of sleep. As these cycles continue throughout sleep, REM sleep is also seen to increase. Although it is difficult to control our sleep cycles, there is a lot that we can do to prevent this from ever disrupted cycles, and thus to ensure a sound sleep and, if necessary, to help to heal Insomnia.
Donald Saunders is the author of a number of health-related publications discussing the problems of sleep and giving detailed advice on such things as how to cure insomnia. For more information and additional articles on insomnia please visit Help-Me-To-sleep.com
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