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Harmful Effects Of Sunlight on the Human Body
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Can sunlight harm us?
‘Too much of even a good thing is bad’
-- goes an old adage. Wise words that ring true for almost
everything that we come across, sunlight included. All of us need a
little exposure to sunlight. This helps synthesize Vitamin D,
essential for the absorption of calcium in the human body. But too much
exposure to sunlight does not translate into heaps of Vitamin D,
which the body can store and use. Excess exposure damages the skin
and results in blisters, pain and some other symptoms.
Effect of ultraviolet
radiation
Why does this happen? Sun’s rays
consist of ultraviolet (UV) light. And UV rays penetrate the skin
and break down collagen and elastin – the two main components that
make up our skin.
When the skin is exposed to sunlight the production of melanin, the
pigment that gives the skin its color, increases. This pigment
prevents damage to a certain extent by absorbing UV rays. |
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However, the skin’s attempt to protect itself gives the skin a dark
color or what is referred to as a suntan. However, excessive
exposure results in wrinkled and darkened skin.
Light-skinned persons and infants are at a higher risk of damage by
exposure to the sun. This is due to the insufficient quantity of
melanin. Does that explain why infants are swathed in towels when
they need to be taken outside? And does it also explain those wide
brimmed hats that light skinned people wear when visiting sunny
places?
The possibility of skin cancer
Sensitivity to sunlight is also at
times a result of certain diseases or drugs. Constant exposure also
damages the DNA of the exposed skin cells. The body’s natural
processes of attempting to heal itself results in the production of
enzymes that wipe out damaged DNA and initiate the production of DNA
replacement.
This process, if it is prolonged or goes wrong, can cause skin
cancer. People with lighter skins are more susceptible to skin
cancer as their skins contain less melanin, which is the skin’s
natural way of protecting itself.
Genetics also play a role and people with a family history of skin
cancer are at a higher risk. Aberrant genes or genes gone wrong
either due to heredity or due to exposure to UV radiation can cause
skin cancer.
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‘We hit ozone,
ozone hit back’
Those may not be old Confucian words of wisdom, but it
definitely explains skin cancer caused due to a depleted ozone
layer. Such depletion results in increased amount of UV rays
getting through with normal sunlight.
Experts say that increased exposure to direct sunlight when
the sun is at its peak can lead to cancer. If exposure is
unavoidable then adequate protection in the form of protective
clothing, wide-brimmed hats and sunscreens must be used.
Sunscreens contain certain formulations that form a protective
layer on the skin and physically block sunrays. The
effectiveness of a sunscreen lotion is indicated by its SPF –
sun protection factor. So, if you’re buying sunscreen choose
one with high SPF.
(The figure alongside shows how a
depleted ozone layer lets through an excess of ultraviolet
radiation) |
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