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Although sleep may seem like a steady state, it actually consists of several stages that cycle throughout the night. The types of brain waves present at the time (based on amplitudes and frequencies) determine the stage of sleep. Only a brief introduction to the stages of sleep will be presented here because a thorough examination of them is beyond the scope of this site. Most importantly, lucid dreams occur in the 5th stage of sleep, known as the REM (Rapid Eye Moment) stage (note: REM is read as a word, not as each individual letter). As the name alludes to, the most profound discernible characteristic of REM sleep is the bursts of rapid eye movement while dreaming. Although dreaming occurs during the other stages of sleep, the most vivid dreaming occurs during the REM stage.
One complete sleep cycle lasts about 90 to 100 minutes; therefore during an average sleep period a person will experience 4 to 5 complete sleep cycles. The sleep cycle begins with four stages of SWS (Slow-Wave Sleep), also called NREM (Non-REM). Note that after the completion of the 4th stage, the 5th stage does not immediately begin; instead, the first 4 stages quickly reverse and are then immediately followed by a REM period. The first REM period will occur roughly 90 minutes after falling asleep; thus the first REM period will last only about 10 minutes, given the length of each sleep cycle being roughly 100 minutes. The length of the stages is not static, however: as the night proceeds, the length of stages 3 and 4 (also called delta or deep sleep) begins to wane, and the length of REM sleep increases, up to about one hour in length after a number of cycles. Therefore, as the night goes on, you dream for longer periods of time.
The following table offers a summary of the stages of sleep:
1
(SWS or NREM) |
4 to 8 |
alpha,
theta |
- transition state between sleep and wakefulness
- eyes begin to roll slightly
- consists mostly of theta waves (high amplitude,
low frequency (slow))
- brief periods of alpha waves, similar to those
present while awake
- lasts only for a few minutes before moving on to next
stage
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2
(SWS or NREM) |
8 to 15 |
theta,
spindles,
k-complexes |
- peaks of brain waves become higher and higher (sleep
spindles)
- k-complexes (peaks suddenly drastically descend and then
pick back up) follow spindles
- again, only lasts for a few minutes
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3
(SWS or NREM) |
2 to 4 |
delta,
theta |
- also called delta sleep or deep sleep
- very slow brain waves, called delta waves (lower
frequency than theta waves)
- 20 to 50% of brain waves are delta waves; the rest are
theta waves
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4
(SWS or NREM) |
0.5 to 2 |
delta,
theta |
- again, also called delta sleep or deep sleep
- more than 50% of brain waves are delta waves; the rest
are theta waves
- last (and deepest) of the sleep stages before REM sleep;
stages reverse and then REM sleep begins
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5
(REM) |
> 12 |
beta |
- beta waves have a high frequency and occur when the brain
is quite active, both in REM sleep and while awake
- frequent bursts of rapid eye movement, along with
occasional muscular twitches
- heart may beat faster and breathing may become shallow and
rapid
- most vivid dreaming occurs during this stage
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Now that you understand when you have the most vivid dreams during the night, you should move on to developing dream recall.
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The information presented here regarding the stages of sleep was collected from and collaborated by several online and offline sources.
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Copyright © 2006 Top Cola Inc.
Site established February 5, 2001; forum started June 18, 2003
Banner artwork by Brent Pauba
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