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
Time zone changes
Changes in routine such as staying up late or
sleeping in afternoon
Medical problems including Alzheimer’s or Parkinson
Mental health problems.
HOW TO MANAGE 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.