Everyone dreams, even if the dreams are not recalled upon awakening. There is no one who doesn't dream, even though they might say they do not. There are two phases of sleep: the passive phase and the active phase. During the passive phase, not much is happening, although the brain still may show some activity at the electrical level. Dreams happen during the active phase in sleep when REMs occur. REMs happen for everyone during sleep.

REMs are an indication that a dream is taking place. It is believed that the eye movements are a reaction of the dreamer to the events happening in the dream. Not only the eyes move, but also fingers and other muscles twitch, depending on what is happening during the dream. During the active state, the brain burns just as much fuel as it does in waking life. No human has ever been discovered yet who does not have REM periods during sleep. Some yogis in the past have claimed that they no longer need dream time and therefore do not dream. As of yet, this has never been documented or tested.

Everyone has watched a cat twitch during sleep. It certainly appears that the cat is trying to catch a mouse or a bird, or is running and jumping. The reason that the body does not act out more than just a few twitches or eye movements during a dream is because a natural sleep paralysis is induced in the body during sleep, in animals and humans alike. This was certainly good planning on nature's part! This is also why it might seem so difficult to wake up at times, or once awake, cannot move for the first minute or so. Dream paralysis will be discussed in more detail later in this material.

When one falls asleep, there is a progression of levels one passes through before the sleep state is actually achieved. First is the transitional state between drowsy wakefulness and light sleep. This stage is short and is marked by small dreamlets, or hypnagogic images. The word hypnagogic originates from Greek, meaning "leading to sleep." The second stage is bona fide sleep with brain wave patterns called "sleep spindles" or "K-complexes." Thought processes are sparse. In the third stage, about twenty to thirty minutes into sleep, Delta is reached. This signifies that long slow brain waves are happening. None, or very little, dream activity happens in this phase. It is said in some ancient East Indian texts that this is the stage of sleep where we are in direct contact with our innermost consciousness, or original consciousness. After lingering in Delta sleep for about thirty or forty minutes, one comes back up to the second stage about seventy to ninety minutes after sleep first started. After five or ten minutes of REM, one moves back into stage two and then back into Delta again. REM is achieved approximately every 90 minutes during the night, with more REMs closer together, even a half hour apart, closer to morning. REM periods last longer closer to morning. After REMs, it is common for a brief awakening to happen, although one usually forgets about it because falling back to sleep happens so quickly and seamlessly.

There are four types of brain waves: Beta, Alpha, Theta and Delta. These states are described as follows by D. Scott Rogo in his book Leaving The Body (1983). Beta brainwaves are the most predominate and are typical of waking consciousness in everyday life. Beta waves register between 14-30 cycles per second and accompany intellectual activity, such as problem-solving. When one relaxes and clears the mind, but is still alert, the brain waves slow down to 8-12 cycles per second. These are called Alpha brainwaves. A typical Alpha state happens when one watches TV. The next layer down in consciousness are Theta waves, which register between 4-7 cycles per second. These waves can appear during sleep but they can also occur during deep meditation. Theta waves are somewhat uncommon and fall between alpha and delta waves. They manifest when a person is involved in a deep alteration of consciousness, like meditation or creative inspiration. Theta waves are not unknown to appear during the deep sleep and delta phases, and are often present during a lucid dream or astral projection (leaving the body, not in a dreamlike world, but a parallel version of the physical world). People who have theta brainwave activity often report having lucid dreams, out-of-body experiences or divine revelations. Theta waves have something to do with divine experiences of all sorts, whether awake or asleep and are often accompanied by a divine floating feeling or inner spaciousness. Delta waves are the deepest, longest and slowest brainwaves and only appear during sleep at ½-3 cycles per second. They cannot appear during meditation.

In the book Our Dreaming Mind (1994), Robert L. Van de Castle, Ph.D. describes these brainwave patterns in more depth. Alpha is actually split into two levels instead of one. Alpha 1 is alert wakefulness, very short small waves, 12-30 cycles per second. Alpha 2 is described as the restful alertness, rather than wakeful alertness, and is quite different from Alpha 1. It has a greater amplitude and a frequency of only 8-12 cycles per second.

Things get interesting when Delta waves enter the picture. They are very high-amplitude slow-frequency waves at 1-2 cycles per second. In stage 2 NREM Delta waves and alpha waves are somewhat mixed, delta waves making up 20% of the mix. Stage 2 NREM is marked by sleep spindles, or spikes, with a frequency range of 12-14 cps. Stage 3 contains between 20-50 % delta waves, and 4 NREM contains more than 50% delta waves. This is when deep sleep has been entered. Here, the delta waves are somewhat regular and a pattern is more easily seen, but some spindles are still present. Stage 2, 3, and 4 NREM delta sleep are noted for the sleep spindles, or K-complexes, where cycles speed up and are irregular in between the deeper rhythms of delta, stage 4 NREM being the calmest with the highest percentage of delta waves.

Stage 1 NREM and stage 1 REM are almost the same brainwave patterns, but are differentiated by the presence or absence of rapid eye movement. In stage 1 NREM state there are sharp vertex waves from the crown of the skull that are not present during REM periods.

The deepest sleep is gotten in the earlier parts of the night, based on the patterns between REM and NREM sleep. The unfolding of sleep moves from drowsiness into Stage 1 sleep. Stage 1 is passed very quickly, descending into stage 2, 3 and 4 NREM. Most of the time is spent in stage 4. Ninety minutes after stage 1 NREM, there is a rise into stage 3 again, and soon stage 1 reappears, lasting about 5 minutes. There may or may not be REMs, for sometimes the dream is not very active, or doesn't form fully for some reason. Then there is a drop back into Stage 2 or 3. Very seldom, and if so only briefly, is there a return to stage 4 sleep after the first REM period. Most of the time will be spent in stage 3 NREM before the next REM period, which appears 90 minutes after the first one. For the rest of the night, most of the time is spent in stage 2 NREM before returning to REM.

As the night goes on, succeeding REM periods become longer and longer, reaching as much as 25 – 45 minutes. For the normal adult, and this is of course only an average among many subjects, REM time is 22% of the entire sleep period. The rest of the sleep is spent 50 % of the time in stage 2 NREM, 7% spent in stage 3 NREM, 14% spent in stage 4, and 7% spent in stage 1 NREM without rapid eye movements.

There is no difference in sleeping patterns between the sexes, but there is a difference in ages. A normal infant spends 50% of its sleeping time in REM, and a premature infant spends as much as 70 – 80 % of its time in REM. Young children under four years old have decreasing time spent in REM until they reach the same patterns as an adult by the age of four. Young children still have a higher percentage of sleep spent in stage 4 NREM, than adults, during which time growth hormone is secreted.

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