....................................................................................
Your Biological Clock And Melatonin
About Biological Rhythms
BY CHRIS OPFER
Remember
that scene in "My Cousin Vinny" where Marisa Tomei says, "My biological clock is ticking likes
this" and she starts stomping hard on the floor?
When
someone says that a woman's biological clock is ticking, it usually means that
she actively wants to have a baby and feels time may be short. Scientists
debate whether this is a real physiological response from the body as fertility
decreases or if it's all in the head [source: Lewin].
While
men can feel a biological clock ticking too, it's generally not with the same
urgency, as their time to father a child is much longer than a woman's is to
have one.
At
least, that was conventional wisdom. As both men and women are becoming parents
at older ages, scientists have discovered that the father's age may have more
to do with a child's genetic health than that of his or her mom [source: Carey].
That's just one use of the term
"biological clock."
Turns out that every living thing –
men, women, animals, plants, insects, and algae – all have internal "body
clocks" determined by a variety of biological rhythms.
These physical, mental and behavioral
patterns follow a predictable cycle every day, one that is determined largely
by the body's response to light and dark [source: EarthSky].
So why do we have these clocks, and what do they do for us?
Here are 10 facts that may surprise you.
10 It's a Complex Clock
The body clock isn't some rinky-dink Mickey Mouse watch. In
fact, it's a series of clocks controlled by a single "master clock"
located in the brain.
The
system works like this: Genes within the body include instructions for making
proteins, which are produced in waves that rise and fall over the course of a
day in a type of 24-hour cycle [sources: NIGMS, EarthSky].
The
master clock manages these circadian rhythms using a group of roughly 20,000
nerve cells called the suprachiasmatic nuclei (SCN), located
in the hypothalamus.
This
section of the brain sits above the optic nerve and produces the hormones that
govern body temperature, hunger, sex drive and other workings of the
body.
The
patterns created not only dictate when we eat and sleep, but also control heart
rate and the production of blood cells and blood sugar.
Although
the genes and proteins generally determine individual rhythms, outside factors
related to light and dark can also have a significant impact on how your body
"tells time" [sources: NIGMS, Healthline, University of Utah].
9 Melatonin Is Our Body's Sleep Aid
Among
the many hormones pumped through the body, the suprachiasmatic nuclei (SCN)
controls the production of the one that makes people want to curl up in a ball
on the nearest couch and catch a few zzzs.
Melatonin is a naturally occurring chemical that helps
regulate the circadian rhythm. The more of it that the body produces, the more
likely you are to get sleepy [source: EarthSky].
Your
melatonin production schedule varies based on light. Remember that the SCN is
located just above the optic nerve, which sends information from the eyes to
the brain.
The
less light that comes in – after the sun goes down and the sky becomes dark,
for example – the more melatonin the SCN tells the brain to make [source: University of Maryland].
Some folks who suffer from sleep
disorders will pop melatonin pills to help them get some rest.
The effect of these supplements,
which are available without a prescription and not regulated in the same way as
pharmaceutical drugs, is still not clear.
Experts warn that users should be
careful to monitor the size and timing of doses so as not to throw off their
natural body clocks [source: National
Sleep Foundation].
8 The
Body Clock Adapts to Location Change
Think
about the body clock as a human version of the one on your smartphone.
If
you turn off the phone when you board a plane in New York and turn it back on
when your flight lands in Los Angeles, you will notice that the clock
automatically adjusts the time to reflect that you're now in a different zone.
In the same way, your body clock will eventually adjust to the new light/dark
cycle on the West Coast [source: Newitz].
Anyone
who's ever suffered from jet lag knows that the shift doesn't happen right
away.
Your
body has been trained to release melatonin at a certain time each night, and
will initially continue to do so even when the optic nerve tells the brain that
it's still light outside.
Eventually
however, and your brain will time the melatonin release to the darkness.
In
other words, the clock slowly rewinds itself to reflect the rising and falling
of the sun and to ensure that you don't spend all of the prime California beach
time snoring in your hotel room [source: Newitz].
7 But It Doesn't Adapt to Daylight Saving
Time
Most
American, Canadian and European timepieces spring forward every March, when the
powers that be move the official time up an hour so as to allow people to make
the most of daylight.
Thought
to be originally cooked up by Benjamin Franklin, daylignt saving time took
hold during World War I and became the law of (most) of the land in the U.S. in
1966.
Then-President
Lyndon Johnson signed legislation requiring official timekeepers to move their
clocks forward an hour each spring and back an hour every fall [source: Espenak].
The
problem is that no one seems to have consulted our body clocks before agreeing
to this twice-a-year adjustment.
Moving
the time ahead an hour does a number on circadian rhythms, particularly in the
days immediately after the change when the sun still comes up around the
same time.
If
your alarm goes off at 7 a.m. the day after it springs forward, your body still
thinks it's 6 a.m. Because the sun rises later in small increments, it's
probably still dark out, and will remain dark for a few months.
That
means that your body won't shut off the melatonin faucet just yet. One study
showed that people's circadian rhythms never fully adjust to daylight saving
time and sleep behavior only returns to normal when we go back to regular time [source: Reinberg].
6 Birds Do It, Bears Do It
It's
like the music group Bloodhound Gang says: "You and me, baby, ain't
nothing but mammals."
Other
mammals also have rhythm-based body clocks that dictate when they rise in the
morning and when they lie down for some shut-eye at night.
In
fact, bears depend on seasonal circadian rhythms to tell them when to
hibernate for the winter and when to come out from their hiding places.
Birds
similarly fly south for the winter based on circadian (or circannual) rhythms
that adapt to changes in temperature and the decreasing amount of sunlight per
day [sources: Newitz, Quraishsi].
It
isn't just mammals who keep time naturally either.
Internal
rhythms drive plants to open their leaves at dawn and close them at night. They
also determine when flowers bloom seasonally [source: American Society of Plant
Biologists].
5 Circadian Clocks Are As Old As Time
The
Salisbury Cathedral in England is said to be home to the world's oldest clock.
The
mechanical device's wrought iron hands are believed to have been tracking the
passage of time since at least 1386.
The
clock survived war, fire and inattention before being rediscovered in the early
20th century and restored [source: Salisbury Cathedral].
The
Salisbury Cathedral clock is but a wee whippersnapper when compared to the
natural clocks that track our circadian rhythms.
Circadian
rhythms developed so that some creatures feed during the day and others do it
at night. Others say the body clock evolved in algae to stagger the sludge's
processes for photosynthesis — converting light into energy to be stored for
later — and nitrogen fixation — in which plants convert nitrogen from the air
into energy — so as not to counteract one another [source: Newitz].
4 Sleep, It Does a Body Good
Perhaps
the reason for circadian rhythms in humans is simpler: They help you sleep, and
sleep is good for you.
When
you lay your head down and nod off to the feather ball, your body is restoring
itself. That includes basic upkeep and repair like muscle growth, tissue
maintenance, protein production and the release of growth hormones.
Those
hormones help children develop naturally — exhibit A in the case against little
Johnny staying up to watch Jimmy Fallon — but also play a key role in helping
adults rebuild tissue over time.
In
fact, it's believed that some of these functions only happen during sleep
hours. Animals deprived of sleep will lose all immune function and die in just
a few weeks [source: Harvard Medical School].
If you've ever popped out of bed
after a nice long slumber and felt mentally refreshed, it's probably not just
because you spent the night dreaming about being fanned and fed grapes by
models poolside at an Italian villa.
Sleep helps humans restore their
mental energy and cognitive functions that often get tapped out during waking
hours [source: Harvard
Medical School].
Our circadian rhythms naturally make
us sleepy at night.
3 The Post-Lunch Dip is Natural
Ever
wonder why you have to fight the urge to sleep after lunch (unless you're
lucky enough to work from home and can give into it)?
Your
body's circadian rhythm is in a natural resting place after your noontime meal.
There's
also another system called the sleep/wake homeostatis that
tells your body when it's time to sleep, which also occurs after you've been
awake for a long time.
By
2 p.m., you've usually been awake for at least eight hours. Put those two
systems together, alongside a heavy lunch, and it's no wonder you want to take
a nap [sources: National
Sleep Foundation, Korkki].
Not
everyone has this feeling to the same degree but it is a natural one.
In
fact, for most adults, their strongest sleep drives are at 2 p.m. and 2 a.m.,
thanks to their circadian rhythms.
However,
if you got a good night's sleep, your urge to nap at lunchtime will be lessened
[sources: National Sleep Foundation, Korkki].
2 Electronic Light Warps the Body Clock
If
we've learned anything so far, it's that the body clock is wound generally to
correspond to light and dark.
When
it starts to get dark at night, the brain tells the body it's time for a rest
by releasing melatonin into the bloodstream. So, what happens when you
literally flip the (light) switch in the evening?
Artificial light can send mixed signals. Yes, a small and
strategically located night-light may be necessary for navigating from bedroom
to bathroom when duty calls.
But
other lights could throw your body clock into disarray. That includes
illumination coming from a television, computer or smartphone.
Many
people like to wind down for the night by watching the ol' boob tube -- or
streaming entertainment through their computers and tablets.
If
you bring those devices, and the artificial light that they give off, into bed,
however, you may be tricking your brain into thinking it should stay awake [source: Klein].
1 The Body Clock Can Impact the Biological Clock
We've
come right back to the "biological clock."
Research
shows that women who are pregnant or hoping to conceive should listen to their
circadian rhythms and avoid artificial light at night.
Sleep
doesn't just help the body rejuvenate and promote growth in kids; it also
protects a woman's eggs from stress.
That's
because melatonin is believed to have antioxidant qualities and defends
the body against inflammation while stimulating the immune system, particularly
during ovulation [sources: Klein, Nierenberg].
When
the lights go on at night, melatonin production slows or stops.
Experts
say that women who are expecting should maintain steady sleep patterns that
conform with the light and dark cycles going on outside.
That
means eight hours of darkness with little or no interruptions each night. The
dark, not actual sleep, is the key.
The
body produces melatonin as a reaction to darkness and will continue doing so,
even if you can't sleep.
Among
other effects, researchers have found that disruptions in this routine can lead
to attention-deficit/hyperactivity disorder and autism-related disorders in
young children [sources: Klein, Nierenberg].
Author's
Note: 10 Facts About Biological Rhythms
Daylight
saving time is a blessing and a curse. Pushing the clocks ahead an hour come
spring means that the sun will still be up when I leave my office.
This,
of course, allows me to continue believing that I am a real, live human being
rather than some sort of hunchbacked, cave-dwelling hermit who slinks around
under cover of darkness.
On
the other hand, it seems to take me weeks of adjustment to get out of bed on
time after the change.
That's
because I like to get up when the sun gets up.
Call
me crazy, call me a damn dirty hippie, call me late to work, but it is my
humble belief that alarm clocks are for quitters.
If
the Good Lord wanted us to get up earlier, he or she would bring the sun up
accordingly.
Chris Opfer
Chris Opfer has written about everything from genetically-modified rats
on the Galapagos Islands to Middle Eastern barbers who use homemade flame
throwers to cut hair. His work has also appeared in The Atlantic, The Village
Voice, New York Magazine, Pacific Standard and American Way, among other
publications. Chris is a graduate of James Madison University and currently
based in New York City.
No comments:
Post a Comment