Lesson 6 – Science of Sleep
In order to proceed with the science of dreams, we need to briefly explore the science of sleep. We have briefly considered that when the mind falls asleep and the body follows suit. What follows is a period of sleep known as a sleep cycle. This lasts about 90 minutes and we have an average of 4-5 cycles a night. Each cycle in turn has 5 stages.
Starting at the lightest sleep, we transition into deeper states of slow wave (SWS) or NREM sleep until stage 4 which is called Deep Sleep (also a slow wave state). The mind then briefly cycles back through stages 4 to 1 before going into a 5th stage known as REM (pronounced as a single word).
In this stage brain activity becomes quite erratic and this is the stage that dreaming mostly occurs, the most vivid dreaming occurs here too. There is a characteristic rapid movement of the eyes under the eyelids at this point too, hence the name (Rapid Eye Motion)
The amount of REM in each cycle becomes longer and more intense as the cycles progress throughout the night, so the most intense periods of REM sleep are 4 and 5. Dreaming as a consequence becomes more lengthy and vivid at these latter stages so we may have a 10 minute dream period at the start of the night and anything up to 45 minutes during a later cycle. Lucid dreams normally occur in these latter cycles.
A further discussion needs to be briefly addressed here, that is the notion of brain wave activity. In essence the brain vibrates at varying frequencies throughout the day and night. These vibration frequencies are described in terms of Hertz (Hz) and the brain typically vibrates with a frequency of about 4 – 60 Hz. We describe these vibration states as follows
Delta Range – 0.5 to 4 HZ (associated with deep sleep)
Theta Range – 4 HZ to 8 HZ (seen in dreaming sleep, and other mental states where the mind is wandering, like daydreaming and imagining)
Alpha Range – 8 to 13 HZ (relaxed but awake)
Beta Range – 13 HZ to 30 (*) HZ (normal awake state/aware)
Gamma Range – 30 (*) HZ to 60 HZ (associated with consciousness – the brain stops producing gamma waves when we’re put under for anaesthesia, for example)
*Note that there’s a lot of disagreement over where Beta range ends and Gamma range begins.
With REM sleep we are normally experiencing a lot of alpha and theta activity. Knowing this science, as we will see can have pressing advantages to helping us to become lucid. A brief outline of the science will be important to keep in mind in order to fully benefit from the induction methods