[blindza] Exhausted? Reset your body clock

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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