Dream occurrence is not random, but as was demon-layer, it still occurs
in approximately 90 minutes during sleep and lasts about 15-20 minutes.
Dream is considered an intermediate position between waking and deep sleep
sleeping period being assimilated. Dream state (Rapid Eye mouvement) in
man Declare a rapid cortical electrical activity (very close to that of
waking), muscle and eye movements inertia, so another "a biological
existence." In the cortical REM sleep is manifested by a rapid continuous
electrographic activity and lower voltage almost identical to that of
wakefulness. A night of sleep can be represented as follows: individual
passes successively through four stages of sleep that occur slowly in
the first two hours of sleep, which occurs usually after the first phase
of deep sleep lasting about 15 minutes, marking the end of the first cycle
sleep. The second cycle lasts about 85-95 minutes. Thus succeed 4-6 sleep
cycles. A graph to represent in some way during the development of sleep
a night looks like this:
REM - represents about 18-20% of the total duration of sleep in an adult.
During deep sleep hormone secretion presents maximum. Annihilation drug
(eg antibiotics) to disturb deep sleep.