I understand that human sleep has a cycle of five stages that can repeat itself several times (depends on how long one sleeps); these are named based on the fifth stage occurring about each 90 minutes which is named Rapid Eye Movement sleep (REM sleep).
I understand the stages of this cycle are primarily as follows:
This first Non REM stage is actually falling a sleep when still "awake" in a sense:
Naturally a state of calmness with little attention to surrounding environment or ambient; feeling of "floating in the void" if you will;
Likely occurrence of hypnogogig hallucinations such as hallucinating sayings by people close to the person emotionally and socially.
This stage will likely include at least one hypnic jerk.
Neuronal areas communicate with other neuronal areas in ways that produce alpha and theta waves of electromagnetic activity
The general feeling of this stage is commonly considered similar to meditation or daydreaming (extremely focused thought about something in the middle of the day with a bit less attention to the surrounding environment than normal)
The second stage of sleep lasts about 20 minutes; the brain begins to produce very short periods of rapid, rhythmic brain wave activity known as Sleep Spindles;
Body temperature drops down and heart rate starts slowing down.
In this stage, neuronal populations start to communicate with other neuronal populations in such a way that produces electromagnetic delta Waves; the sleeper is transitioning from light sleep to a deeper sleep.
A deep sleep phase of consistent delta activity and likely no dreaming, lasting for about 30 minutes;
Possibly involving the somewhat rare phenomena of Sleepwalking and bed wetting in children; typically at the end of that stage (This does not include the problems that can happen with certain sleep medications).
REM sleep is characterized by Rapid eye movements, increased respiration rate and increased brain activity; paradoxically voluntary muscles become generally paralyzed but some are active (generally without noticing and adjusted to acting felt in dreaming; hence one wakes talking as if someone talked in a bad dream);
Waking up during REM sleep can be faster in a "vivid" fashion due to associative brain areas working (to produce dreaming) and fast communication with primary brain areas.
It is theorized that the general voluntary muscle paralyzation is protective - aimed to prevent or inhibit sharp movements caused per dreaming and keep their sensation as that of associative brain areas (associated with the organs with which one feeling act in a dream) instead the primary ones which would probably cause bruise and bodily harm.
As far as I understand, waking up in stage 4 is a "heavy" wake up in comparison to the "vivid" one described in stage 5.
During all stages of sleep the brain produces and salvages different materials on which it's not the place to elaborate.
I am sorry if I had any mistake or innacuracy in describing the sleep stages → please comment noting any such problem.
I desire to learn if the "90 minutes to REM sleep" notion on which I have learned in the past in an introduction to neuropsychology course, is a strict one or REM sleep could reach way faster than usual, and maybe also be prolonged, by some pathology.
My aim is to understand if there is a pathology of "generally too much REM sleep", hence too much dreaming:
As we live in a planet filled with suffering, inequality, pain, ignorance and other bad phenomena and experiences, than in my opinion such disorder will likely to correlate with nightmare disorder but of course not necessarily → I assume that too much REM sleep might be problematic without dependency in dream content.
Is there a medical problem of too much REM sleep?
That is to ask; is there a widely known pathology of too much REM sleep per se, either by frequently reaching that stage too fast or having this stage too much or both, and is there a therapeutic family adjusted for it (say "REM reducers")?