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Understanding sleep for healthier living and getting the job done
by Miha Thornton
It's always intriguing to hear the latest survey
related to sleep.
And they all have one thing in common and that is people are much
better off getting the recommended hours for healthier living.
That doesn't come as anything new but what are the prescribed hours
we should be sleeping each night and what actually happens when we
lay down and close our eyes every night.
Sleep for human beings is divided into two distinct states; "REM"
(rapid eye movement) also called light or active, and "NREM" (non
rapid eye movement), also called deep or quiet sleep.
When adults fall asleep we generally slip straight into NREM sleep.
Our bodies become motionless, breathing (becomes) is shallow and
regular, our muscles relax and for all money we (are) become "out to
it". After about ninety minutes our brain begins to "wake up" and
starts functioning on a different level, this is when we enter REM
sleep.
During REM, our brain, it could be said, "exercises", we dream,
fidget, roll over, moan and talk in our sleep, even adjust the
blankets without fully awakening. When we wake during the night,
either for no apparent reason or to go to the bathroom it is from
this REM state.
The average adult during a normal eight hour sleep takes seven
minutes to fall asleep and spends around two hours in REM sleep and
six hours in NREM sleep, rotating between the two states about every
ninety minutes.
Infants on the other hand, especially young babies, enter sleep
through an initial twenty or thirty minutes in REM.
This explains why a lot of people especially babysitters and people
unfamiliar with babies sleeping patterns go to painstaking,
meticulous and sometimes bizarre lengths to get baby off to sleep -
only to have her suddenly wake when it looks like the "deals done".
If efforts were to continue for an extra twenty or thirty minutes
until baby has entered NREM sleep there is a far greater chance that
baby will stay asleep.
One would recognize the transition from NEM to NREM sleep. Spasmodic
twitches, muscle tightness, grimaces and even sleep grins would
gradually give way to an overall limpness with breathing becoming
more regular and shallow. If baby needs to be moved it's better to
wait for her to reach NREM state as she can be easily woken whilst
in REM sleep.
Young babies spend approximately half their sleeping time in REM,
dropping off to about twenty five percent by the time they reach
four years of age. Infants sleep cycles occur about every sixty
minutes (that is going from light sleep to deep sleep then back to
light sleep).
Although it might seem like the ultimate wish come true when we hear
about a young baby sleeping through the night, new research is
showing that this might NOT be in the best interests of the baby.
Here's why.
Babies are at their most vulnerable when they are very young. Their
cardiopulmonary regulating systems are not developed enough to cope
well with self arousal from long spells in NREM.
Alternating frequently between REM & NREM stops a baby from falling
too deeply for too long into deep sleep from which she might not be
able to self wake.
This is one of the main theories behind the incidence of SIDS.
Secondly, blood flow to the brain nearly doubles during REM sleep
and researchers theorize this is because this is the time when the
brain develops.
Learning is thought to occur as the brain processes information that
was acquired while awake.
This is further reinforced by the fact that premature babies spend
almost ninety percent of their sleeping time in REM - to protect
themselves from falling into a deep state of sleep for too long and
to help speed up their brain development.
A young baby has a very small stomach (slightly larger than her
fist) and because she digests breast milk very quickly it is
unlikely that she'll sleep for more than four hours, and most likely
for not more than 1 - 2 hours between feeds
After six months babies cardiopulmonary regulating systems have
developed to the point where their bodies are better able to cope
with longer periods of deep sleep and thus the risk of SIDS drops
dramatically.
Adults need between 7 - 8 hours per day for peak condition.
Adolescents need nine and a quarter hours per day, yet American
adolescents average only seven and a half hours with up to 25%
surviving on six and a half hours.
No wonder why they struggle to get out of bed most mornings and
struggle with concentration during school!
Average Ideal Sleep Times
Newborn 16.5 hours
12 months 14.5
2 years 13
5 years 11
10 years 10
16 years 8.5
20 +years 7-8
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