YOUR BODY HAS A CLOCK.

Some people do not even know they have a
body clock called the ‘biological clock’.
Sometimes you experience inability to sleep
at night whenever you had slept in the
afternoon. Do you know why.
Moreover, when you travel let’s say from
Nairobi to Amsterdam, it takes a while for
you to adjust to the new environment-it
doesn’t just occur, but rather due to an
alteration in the body’s biological Clock.
Most people notice that they naturally
experience
different levels of sleepiness and alertness
throughout
the day, but what causes these patterns?
Sleep is
regulated by two body systems: sleep/wake
homeostasis
and the circadian biological clock .
When we have been awake for a long period
of time,
sleep/wake homeostasis tells us that a need
for sleep
is accumulating and that it is time to sleep.
It also
helps us maintain enough sleep throughout
the night
to make up for the hours of being awake. If
this
restorative process existed alone, it would
mean that
we would be most alert as our day was
starting out,
and that the longer we were awake, the
more we would
feel like sleeping. In this way, sleep/wake
homeostasis
creates a drive that balances sleep and
wakefulness.
Our internal circadian biological clocks, on
the other
hand, regulate the timing of periods of
sleepiness and
wakefulness throughout the day. The
circadian rhythm
dips and rises at different times of the day,
so adults’
strongest sleep drive generally occurs
between
2:00-4:00 am and in the afternoon between
1:00-3:00
pm, although there is some variation
depending on
whether you are a “morning person” or
“evening
person.” The sleepiness we experience
during these
circadian dips will be less intense if we have
had
sufficient sleep, and more intense when we
are sleep
deprived. The circadian rhythm also causes
us to feel
more alert at certain points of the day, even
if we have
been awake for hours and our sleep/wake
restorative
process would otherwise make us feel more
sleepy.
Changes to this circadian rhythm occur
during
adolescence, when most teens experience a
sleep
phase delay. This shift in teens’ circadian
rhythm
causes them to naturally feel alert later at
night,
making it difficult for them to fall asleep
before 11:00
pm. Since most teens have early school
start times
along with other commitments, this sleep
phase delay
can make it difficult to get the sleep teens
need — an
average of 9 1/4 hours, but at least 8 hours.
This sleep
deprivation can influence the circadian
rhythm; for
teens the strongest circadian “dips” tend to
occur between
3:00-7:00 am and 2:00-5:00 pm, but the
morning dip
(3:00-7:00 am) can be even longer if teens
haven’t had
enough sleep, and can even last until 9:00
or 10:00 am.
The circadian biological clock is controlled
by a part of
the brain called the Suprachiasmatic
Nucleus (SCN), a
group of cells in the hypothalamus that
respond to
light and dark signals. From the optic nerve
of the eye,
light travels to the SCN, signaling the
internal clock
that it is time to be awake. The SCN signals
to other
parts of the brain that control hormones,
body
temperature and other functions that play a
role in
making us feel sleepy or awake.
In the mornings, with exposure to light, the
SCN sends
signals to raise body temperature and
produce
hormones like cortisol. The SCN also
responds to light
by delaying the release of other hormones
like
melatonin, which is associated with sleep
onset and is
produced when the eyes signal to the SCN
that it is
dark. Melatonin levels rise in the evening
and stay
elevated throughout the night, promoting
sleep.
In teenagers, research has shown that
melatonin levels
in the blood naturally rise later at night than
in most
children and adults. Since teens may have
difficulty
going to bed early to get enough sleep, it
can help to
keep the lights dim at night as bedtime
approaches. It
can also help to get into bright light as
soon as
possible in the morning.
WHAT CAUSES CIRCADIAN RHYTHM
DISORDERS ?
circadian rhythm disorders can be caused
by many
factors, including:
Shift work
Pregnancy
Time zone changes
Medications
Changes in routine such as staying up late
or
sleeping in
Medical problems including Alzheimer’s or
Parkinson
disease
Mental health problems.
HOW TO MANAGEMENT CIRCADIAN RYTHM
DISRUPTION
light is the strongest stimulus for correcting
a person’s sleepwake schedule and careful
control to and avoidance of bright lights can
speed adjustment to a new time zone.

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