Doctors say that this cycle is a heightened anabolic state-a certain
period when the body produces new nervous and muscular tissue and
bone. To put it simply, this is a period when the body grows and being
repaired.
Sleep is triggered by a group of hormones in the body. These
hormones react to cues within the body and in the environment.
There is an approximate 80 percent of sleep time without dreams.
This stage of dreamless sleep is referred to as NREM which stands for
non-rapid eye movement. Dreams occur primarily during rapid eye
movement or REM.
During non-rapid eye movement sleep or NREM, the breathing and
heart rates are slow and the blood pressure goes down. Based on the
Rechtschaffen and Kales standardization of the year 1968, NREM was
divided into 4 stages. However, it has been reduced to 3 by The
American Academy of Sleep Machine in 2007.
Stage 1 - This stage mostly occurs in the start of sleep wherein theta
wave emerges while alpha waves vanish. Those who are aroused from
this stage believe that they have been completely awake. It is also in
this stage when the body experiences hypnic jerks.
Stage 2 - In this stage, dreaming is rare and no eye movement takes
place. The sleeper may also be wakened easily.
Stage 3 - This is also referred to as slow-wave sleep of SWS, wherein
deep sleep takes place. This is also the stage when dreaming occurs.
However, the content of slow-wave sleep is likely to be less
memorable, less vivid and disconnected than those in rapid eye
movement sleep.
On the other hand, rapid eye movement sleep also known as REM, is
a normal phase of sleep making up between20% and 25% of the
whole sleep time. Apart from the swift movement of the eyes, this
stage is also characterized by low muscle tone.
Human beings usually experience 4 to 5 REM sleep periods during a
usual full session of sleep, and the last is longer than the first one.
According to sleep experts, the brain neurons are as dynamic during
rapid eye movement sleep as they are when the body is awake.
However, atonia, a relaxed state of the skeletal muscles, makes the
body paralyzed during REM.
In the succeeding chapters, you will know more about sleep and how
to make the most out of it.
According to National Sleep Foundation, all people need to get the
right sleep because this is how the body recuperates all the energy it
has lost after a tiring day.
Well, this is a no-brainer, so you don't need an expert organization to
tell you how important sleep is. Some of the common signs of lack of
sleep are incapability to multitask, disinhibition, slowed speech,
impaired memory moodiness and irritability.
Disinhibition pertains to poor risk evaluation and lack of self-control.
It commonly results to a reduced ability in managing or editing their
response to a certain situation.
The amount of sleep humans need greatly varies with every person,
yet on average, an adult must have 8 sleeping hours. Some people
have the ability to do well in school or at work with only 6 hours of
sleep, while others require 10.
Sleep is defined as a state when the motor activity and senses are
suspended; there is partial or total unconsciousness, and the
voluntary muscles of the body are not active. It is more reversible
than coma or hibernation, yet responds less to any kind of stimulus
than silent wakefulness. Sleep is very important, as it is the rest cycle
of the body. Get all the info you need here.