[blindza] Exhausted? Reset your body clock
- From: "Jacob Kruger" <jacobk@xxxxxxxxxxxxxx>
- To: "NAPSA Blind" <blind@xxxxxxxxxxxx>
- Date: Tue, 23 Nov 2010 15:42:22 +0200
See article below, but they seem to reckon that light being seen by the eyes
can affect all sorts of daily rythms, inner-body chemical production, behaviour
modes, etc. etc., and just wondering if there are other parts of our bodies
that try to alternately handle things like this..?
Stay well
Jacob Kruger
Blind Biker
Skype: BlindZA
'...fate had broken his body, but not his spirit...'
---article content---
Exhausted? Reset your body clock
November 23 2010 at 10:49am
By LUZY ELKINS
Insufficient exposure to daylight can cause poor concentration. Photo: Steve
Lawrence
Suffer from daytime tiredness? Poor concentration? Feel you've lost your "get
up and go"? If you answered yes to any of these questions, then lack of
daylight could be to blame.
We all know that exposure to daylight is important for avoiding the winter
blues. However, scientists have now found that exposure to bright daylight is
actually vital throughout the year.
Without enough light - and, at the right time of the day - our body clock isn't
set properly. It then races ahead - or occasionally lags behind - the actual
time.
As a result, we feel tired at inappropriate times of the day, suffer from poor
concentration and mood swings, and need stimulants, such as coffee, to keep us
going. We're also more prone to put on weight and develop diseases.
This phenomenon - "social jet lag" - occurs because our modern lifestyles
conflict with the way we evolved. Our body clocks are based on early man's
habits of rising with the dawn and going to sleep as darkness comes.
Bright light in the morning stimulates the production of chemicals such as
adrenalin, cortisol and serotonin which help wake us up, fire our energy and
make us feel mentally alert, says Daniel Adams, a US scientist and expert on
light therapy.
"The production of these 'waking' hormones also help wash away the hormones
that make us feel sleepy. Then, in the evening, as the light fades, the body
clock sends signals to the pineal gland to produce hormones such as melatonin
and adenosine which help induce sleepiness."
That's what should be happening. But, nowadays, we often get up in the dark and
spend much of our time during the day inside in the relative gloom.
Then, as darkness falls, we turn on the lights. Before bed, we go into the
bathroom - often the brightest room - to have a bath or clean our teeth. This
has the equivalent effect on the body of a mug of coffee, waking us up, says
Professor Debra Skene, a neuro-endocrinologist at the University of Surrey.
This limited exposure to natural daylight - and too much light at the wrong
time of day - upsets the body clock. The man who coined the term "social jet
lag", Professor Till Roenneberg, of Munich University, believes many people are
affected by it. "More than 50 percent of us suffer from a social jet leg of
more than two hours, which means that our body clock's time and the social time
are two hours apart.
"That is why so many people struggle to get up in the morning - 74 percent of
people need an alarm clock to wake them - their body clock is behind the real
time.
"They are trying to get to sleep and wake up at a time that is not biologically
right for them."
He adds that tiredness is not the only problem. "Our body clock sets all our
biological features such as our metabolism and kidney function, too. If your
internal body clock is not in synch with real time, it increases the risk of
being addicted to alcohol or cigarettes - as you tend to use alcohol to calm
down at night and cigarettes as a stimulant during the day.
"It also increases the risk of being overweight, because social jet lag makes
us do things at the wrong body clock time, such as eating."
It might also raise your risk of diseases such as cancer. One US study, in
2005, found that having lower than normal levels of the sleep-inducing
melatonin hormone encourages the growth of tumours.
So why doesn't artificial light during the day kick-start the body clock?
Because it is not intense enough, says Skene. "Laboratory studies have found
that the brilliant blue light you get with the white sunlight against a blue
sky is the most effective at helping to make us alert - and ultimately to
sleep."
Only in the past 10 years have scientists such as Professor David Berson, a US
neuroscientist, started to understand the role light and our eyes play in
setting our body clock. His team recently discovered the role of a
light-sensitive pigment in the eye called melanopsin. When it senses bright
light it stimulates the production of nerve signals which send messages to the
suprachiasmatic nucleus - the section of the brain known as the body clock. The
brighter the light, the greater the intensity of the signals sent.
"Our body clock is a bit like a cheap digital clock, it isn't perfect at
keeping time and tends to drift," he says. "It is exposure to light that helps
correct these errors and keeps it to a normal pattern."
Source URL:
http://www.iol.co.za/lifestyle/exhausted-reset-your-body-clock-1.875771
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