What happens when we sleep?

Sleep, a real necessity in life, is a fascinating phenomenon that occurs at least daily in our lives.
Before now, sleep was thought to have been an inactive state in which both the brain and the body shuts down in order to rest from the day's work. But scientists have found out that sleep in itself is an activity in which the Brain is most times more active than when we're awake.
Sleep has an immense influence on our physical and mental well-being.
Understanding what happens during sleep is the main aim of this article.

THE SLEEP CYCLE

 
We've got to know that sleep is a series cycle each consisting of 4 stages. These stages can be classified in 2 parts, the first 3 being non-rapid eye movement (NREM) and the other being rapid-eye movement (REM).

Sleep begins at NREM-1. it's that point where we cross from wakefulness to sleepiness, you know that point where your eyes starts making slow movements and you're having a hard time keeping it from shutting? that's the 1st stage of sleep... NREM1 is that kind of sleep you're getting into right before the Usher taps you in church. 

On to stage 2 where the sleep goes deeper than stage 1. At this point, breathing becomes relaxed, Neural activities are decreased and body temperature drops.
stage 3, is what is known as the ''deep sleep stage''. This is a very difficult stage to wake a person.
Stage 4 sees a transition to REM sleep, the part where most of our dreams occur.
the whole cycle goes between 90-120minutes then we're back to stage 1 again. each stage vary in length, so as the night goes on, the time for NREM decreases while time for REM increases, this could explain why most times, we are in the middle of a dream when we are awoken for the day, that is because REM sleep becomes very long towards the later parts of the night.

SOME INTERESTING THINGS THAT HAPPEN DURING SLEEP

The time we sleep, is the time the brain takes to do maintenance work on the body. Growth hormones are secreted at that time, also hunger hormones are secreted too. There is a general clean up of the body system where toxic waste are cleared away for excretion.
Also, during sleep, the brain sorts out information received during the day. We go through the whole day receiving information from different sense organs of the body, while we sleep, the brain filters out the information not needed while the important information gets 'cemented in' , this filtering process is sometimes reflected in our dreams. 

Speaking of dreams, ever wondered why we don't usually act out our dreams no matter how real things might look? well that's because we are literally paralyzed during our sleep. Only muscles in the eyes are allowed to move (that's why it's called Rapid Eye movement sleep). Muscle paralysis is a method employed by the body to prevent us from scoring the World Cup winning goal, hitting the lecturer who decided to punish us for late coming, and other wild activities we dream of. Although the paralysis is temporal, it is totally important for obvious reasons.
for Parasomnias e.g. sleep walking, sleep talking. . . this occurs during stage 3 (deep sleep stage). During that stage the body is less responsive to external stimuli and that's why it is usually difficult to get  the sleep talker to shut up during his conference meeting. Unfortunately, just like other sleep disorders, Scientists have no good clue as to why they occur.
As a matter of fact, much of what we know about ''Sleep'' is from studies based on sleep deprivation, but there is hope as more researches are made and with advancement in technological methods, we might be able to study more deeply the wonderful state called Sleep.