UV Facts: UVA vs. UVB


Reprint of an article by Lori Valesko from the Article Codex website, articlecodex.com


Introduction by Dr. Don Rose, Writer, Life Alert




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 from.


The sun has 2 types of UV (ultraviolet) rays: 1. UVA; 2. UVB.


UVA: Long-wave 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 melanomas.


UVB: Short-wave 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 radiation.


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.



The article above is covered by a Creative Commons Attribution-NoDerivs 2.5 License. The information provided is, to the best of our knowledge, reliable and accurate. However, while Life Alert 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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