THE DREAM DICTIONARY

When attempting to analyze and interpret your dreams, it is important to know that every human being, of every age, and from every part of the world, dreams anywhere from four to seven times each and every night. There is even evidence that babies experience dream sleep while still in their mother's womb. What they dream about, of course, is a mystery. What animals dream about is a mystery as well, but most mammals dream as well.
The sleep cycle is divided into four distinct stages, and every person cycles through all four stages each and every night. Every cycle contains a stage of dream sleep, and every person experiences a number of distinct dream stages, and a number of distinct dreams every night.
Typically the only dreams that are recalled, if any are recalled at all, are those dreams that take place closest to waking. The closest the dream occurs to waking, the more likely it is to be remembered. If a dreamer is woken in the middle of dream sleep, he or she will remember his or her dream perfectly and vividly in even the tiniest detail. We know this from years of studies of dreams.
You may be surprised to know that science is still unsure of the exact function of dream sleep. We do know, however, that dreams are absolutely essential to our psychological and physical health. Research volunteers given drugs to disrupt dream sleep experienced all manner of psychological problems, including problems concentrating, irritability and even waking hallucinations.
Let's explore the four stages of sleep, including dream sleep, in greater detail.
Stage 1:
The first stage of sleep is a very light one, and it is very easy to be awoken or disturbed during this stage. Stage one of sleep usually lasts for only a few minutes, and the sleeper quickly moves on to stage two.

Stage 2:
Stage two is a much deeper level of sleep than stage one. It is in stage two of sleep that dreams begin to form. At this point in the dream cycle, there are usually no clear images. Dreams at this stage mostly consist of vague ideas and thoughts drifting through the dreamer's mind. The sleeper will continue and enter stage three.

Stage 3:
Stage three is a still deeper sleep. In stage three of the sleep cycle the sleeper's muscles have all relaxed, and his or her heart rate and respiration have both slowed down. The sleeper's blood pressure also falls during this stage of sleep, and the breathing is even and steady. During this deep stage of sleep, the sleeper would be very difficult to awaken. Typically the sleeper can only be awakened by a very loud noise or the shout of his or her name. After a time, the sleeper will enter the final stage of sleep.

Stage 4:
Stage four of sleep, also known as REM, or rapid eye movement sleep, is the deepest stage of sleep, and the one in which the most dreams occur. During this stage of sleep it is very difficult indeed to wake the sleeper. During REM sleep, the blood pressure and heart rate will fluctuate, and the sleeper's brain will light up. Studies of dreaming patients have shown that more brain activity occurs when we are dreaming than when we are awake.

It is the rapid movements of the eyes under their closed lids that give REM sleep its name, and these eye movements are the distinguishing characteristic of dream sleep, and proof that dreams are occurring. Most REM sleep lasts only for about 10 minutes. After that time, the sleeper returns to the deep sleep that characterizes stage four of the sleep cycle. The sleeper will return after a time to a period of REM sleep, then cycle back into stage four. This process is usually repeated from four to seven times a night.