"From technological breakthrough to health risk epidemic" would
be the historical parable of artificial light according to an article in
the pages of "Nature" written by Charles Czeisler, of the Department of
Sleep Medicine at Harvard Medical School.
Artificial light is one
of the factors most strongly associated with sleep deprivation, a
condition very common in our society and one that can lead to a number
of pathological conditions which are becoming more ever more prevalent
including obesity, diabetes, cardiovascular disease, depression and
stroke.
Recent research in this field, conducted both on animals
and humans, has shown that staying awake longer alters the expression of
hundreds of genes. At the behavioural level we have seen, for example,
that prolonged wakefulness causes you to eat more than the actual energy
needs of the body. There are measurable effects on the immune system:
to keep its balance, the body needs a sufficient number of hours of
sleep per night.
Even more obvious are the effects on the mental
faculties: to be most affected are the attention span, concentration and
learning, and also the mood can pay the price. Moreover, lack of sleep
leads to increased state of anxiety and depression that some studies
have linked even to a higher rate of suicide.
About one third of
adults now complain about insufficient number of hours of sleep compared
to 3% fifty years ago. Children fare no better, with data showing that
worldwide, children sleep on average 1.2 hours per night less than a
century ago.
The causes of this shift are certainly found in the
move towards the production of goods and services 24 hours a day, 7 days
a week, with people working longer hours and increasingly on night
shifts. Of equal impact however are the voluntary and recreational
activities of going out and watching TV.
In all this, the role of
artificial light is rarely emphasized, but it is essential. Our ears
have two functions: that of hearing and balance. Equally our eyes, in
addition to the function of vision, act as transmitters. Via the
ganglion cells of the retina, they send information about the presence
of ambient light. And it is light which is the most important of all the
signals that regulate the circadian rhythms, or our "internal clock".
Once
in the brain, these signals trigger a series of different effects. They
inhibit neurons that promote sleep, suppress the release of melatonin,
which is important for the regulation of sleep-wake cycles from the
pituitary gland, and activate neurons' orexin in the hypothalamus which
promote wakefulness.
Over millennia the human being has evolved
according to the circadian rhythms set by natural light. In less than a
century however, artificial light has proliferated our environment to
such an extent that in inhabited areas total darkness no longer exists.
In other words, both we and the natural world around us are
understanding night time to be day.
Moreover, the advent of low
energy LED is compounding the problem as its light has a wide variety of
components from the blue-green spectrum, which the ganglion cells of
the retina are more sensitive to. Artificial light will continue to
signal more and more that it is not time to sleep, and as increasing
numbers of devices such as TVs and computer screens utilise LED
technology, the problem will only get worse.
Fortunately, the
mechanisms by which the artificial light suppresses sleep are now more
clear, allowing us to better remedy the problem. Scientists, for example
are already developing technologies which minimise the blue-green
component of LED in favour of the yellow orange. Ultimately however, the
best solution lies within our own grasp... Reduce the time we site in
front of TV's, laptops and tablets after dark!
The Author writes for Lightbulb World. For more information on
Domestic and LED lighting, and a massive stock of light bulbs and
fittings of all types, please visit www.lightbulbworld.co.uk
Article Source:
http://EzineArticles.com/expert/Julian_M_Jones/2145653
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