Tuesday, June 17, 2008

The Sun and How it Causes Damage to Your Skin

Ultraviolet (UV) light rays emitted by the sun are the cause of damage to our skin. This damage may be visible as age spots, fine or not so fine lines on our face, or simply skin that has lost its elasticity. Exposure to the sun can also lead to skin cancer. The National Safety Council estimates that one in five will develop skin cancer. A sunburn will fade, but damage to deeper layers of skin remains and can eventually cause cancer. That’s why you should start sun-safe habits now that will last a lifetime.

Sunlight contains three types of ultraviolet rays: UVA, UVB, and UVC.

UVA rays cause skin aging and wrinkling and contribute to skin cancer, such as melanoma. Because UVA rays pass effortlessly through the ozone layer (the protective layer of atmosphere, or shield, surrounding the earth), they make up the majority of our sun exposure. A UVA tan does not help protect the skin from further sun damage; it merely produces color and a false sense of protection from the sun.

UVB rays are also dangerous, causing sunburns, cataracts (clouding of the eye lens), and immune system damage. They also contribute to skin cancer. Melanoma, the most dangerous form of skin cancer, is thought to be associated with severe UVB sunburns that occur before the age of 20. Most UVB rays are absorbed by the ozone layer, but enough of these rays pass through to cause serious damage.

UVC rays are the most dangerous, but fortunately, these rays are blocked by the ozone layer and don’t reach the earth.

UV rays react with a chemical called melanin that’s found in most people’s skin. Melanin is the first defense against the sun because it absorbs dangerous UV rays before they do serious skin damage. Melanin is found in different concentrations and colors, resulting in different skin colors. The lighter a person’s natural skin color, the less melanin it has to absorb UV and protect itself. The darker a person’s natural skin color, the more melanin it has to protect itself. Its important to remember that both dark and light-skinned people need protection from UV rays because any burning causes skin damage.

As the melanin increases in response to sun exposure, the skin tans. But even that “healthy” tan may be a sign of sun damage. The risk of damage increases with the amount and intensity of exposure. Those who are chronically exposed to the sun are at much greater risk.

A sunburn develops when the amount of UV exposure is greater than what can be protected against by the skin’s melanin. Unprotected sun exposure is even more dangerous for individuals with moles on their skin, very fair skin and hair, or a family history of skin cancer, including melanoma.

Also, not all sunlight is “equal” in UV concentration. The intensity of the sun’s rays depends upon the time of year. UV rays are strongest during summer. With the right precautions, you can increase your level of safety while in the sun.

Most sun damage occurs as a result of incidental exposure during day-to-day activities. Even on cloudy, cool, or overcast days, UV rays travel through the clouds and reflect off water abd bombard your skin. Clouds and pollution don’t filter out UV rays, and they can give a false sense of protection. This “invisible sun” can cause unexpected sunburn and skin damage.

One of the best ways to protect your skin from the sun is to cover up and shield skin from UV rays. Ensure that clothes will screen out harmful UV rays by placing your hand inside the garments and making sure you can’t see it through them.

Lots of good sunscreens are available including formulations for sensitive skin, long-lasting waterproof and sweat-proof versions, and easy-application varieties in spray bottles. What matters most in a sunscreen is the degree of protection from UV rays it provides. When faced with the overwhelming sea of sunscreen choices, concentrate on the SPF (sun protection factor) numbers on the labels. Generally speaking, SPF indicates how much longer a person wearing sunscreen can stay in the sun before beginning to burn than they would without using any sunscreen at all. SPF numbers generally range from 2 to 50. The American Academy of Dermatology and the Sun Safety Alliance (SSA) recommend an SPF of 15 or higher.

- Dave Riches

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