UV Facts: UVA vs. UVB
Reprint of an article
by Lori Valesko from the Article Codex website,
Introduction by Dr. Don Rose, Writer,
While it is good to maintain a sunny outlook
on life, look out – a sunny day (exposure to it, that is) can actually be bad for
your health. The reason: the potential for sun damage to our skin. The article below
addresses this “dark side” of the sun – in particular, its two types of harmful
ultraviolet (UV) rays: UVA and UVB. --Don Rose
We all know the
sun can damage our skin causing premature aging and even cancer, but most of us
don’t know how or why. It can be hard to know what to look for when you need to
protect your skin as it’s easy to get confused about which UV ray does what. It’s
easier to know how to protect yourself if you know what you’re protecting yourself
The sun has 2
types of UV (ultraviolet) rays: 1. UVA; 2. UVB.
solar rays of 320-400 nanometers (billionths of a meter). You’re almost never safe
from exposure to UVA rays as they can go through windows, light clothing and even
your windshield, so if you’re outside you’re getting exposed to UVA rays. UVA rays
are responsible for aging. They are less likely than UVB to cause sunburn but UVA
penetrates the skin more deeply, causing wrinkling and leathering of the skin. Prolonged
exposure to UVA cracks and shrinks the collagen and elastin of our skin. Collagen
makes up 75% of our skin and is the fibrous protein of skin, cartilage, bone, and
other connective tissue. Along with elastin, it is responsible for skin strength
and elasticity, and its degradation leads to wrinkles that accompany aging. Elastin
is a protein in connective tissue that is elastic and allows the skin to resume
its shape after stretching or contracting. When UVA rays damage these components
of our skin it loses strength and elasticity, thus causing wrinkles, sagging, leathery
skin and… aging! If that’s not bad enough, studies show that UVA not only exacerbates
UVB's carcinogenic effects but may also directly induce some skin cancers, including
solar rays of 290-320 nanometers. UVB rays are more potent than UVA in producing
sunburn. Therefore these rays are considered the main cause of skin cancers (basal
and squamous cell carcinomas and melanoma). Sometimes called the "tanning ray",
UVB rays stimulate the melanocyte cells (located in the bottom layer of the skin)
to produce the brown pigment melanin, producing a suntan as a defense against UV
So even if it's
a cloudy day and you're driving in your car you're getting exposed to the harmful
UV rays of the sun. That's why it's so important to protect your skin with sunscreen
and UV protective clothing at all times - especially if you're working, playing
or vacationing outside.
About Lori Valesko
A surfer for over 30 years, Ms. Valesko owns
and operates http://www.BeachTrading.com where you can find quality beach apparel and
accessories including UV protective clothing and sunscreen.
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Attribution-NoDerivs 2.5 License.
The information provided is, to the best of our knowledge, reliable and accurate.
However, while Life
always strives to provide true, precise and consistent information, we cannot guarantee
100 percent accuracy. Readers are encouraged to review the original article, and
use any resource links provided to gather more information before drawing conclusions
and making decisions.
Dr. Don Rose writes books, papers and articles
on computers, the Internet, AI, science and technology, and issues related to seniors.
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