 | |  UVA-UVB Sun Rays
"U" ltra "V" iolet Light Rays
Sunlight has three categories, ultraviolet, visible and infra-red rays. Rays are put into a category according to their wave length. The wave length is the distance from the sun to the earth. We are only going to address ultraviolet rays and their effects in this section. Ultraviolet is divided into three sections according to their wave lengths and listed accordingly.
1. UVC usually does not reach the earth's surface being absorbed by the ozone layer above the earth. Occasionally articles are written on the ozone depletion and the possible exposure to UVC where only a brief exposure can cause a light sunburn. Prolonged exposure to UVC is considered fatal. This ray is the shortest wave length from the sun.
2. UVB long considered the "tanning ray" is strongest in the summer months when the earth rotates closest to the sun. When the earth rotates away from the sun in the winter months it is harder to get a "suntan" because the rays can not reach the earth's surface. Sunblocks for many years only blocked the UVB ray as science was not clear on the body's reaction to UVA.
Body's Reaction to UVB
This ray only has the strength to penetrate the epidermis. The epidermis is the very top layer of the body and the same thickness as a silk scarf. No blood vessels or nerve endings are present and is composed of keratinocytes (skin cells), basal cells and melanocyte cells. Melanocyte cells synthesize tyrosinase and the pigment melanin that is transferred to the keratinocytes or skin cells for color. See the hyperpigmentation or brown spots information section of the store for more facts on darkening of the skin. UVB rays simulate the melanocyte cell to produce more melanin which is more color known as a suntan or if a very small area known as a brown or age spot.
3. UVA was touted in the "80's" as the safe ray and sun beds were the rage. Some dermatologist backed this idea as a safe and healthy way to look your best. Since then science has found this ray actually does the most amount of damage to the body than UVB. UVA is the same strength year round -- it does not matter how close or how far away the sun is from the earth. The ray remains the same strength and considered a light X ray. It goes through light clothing, wind shields, office windows, hats, etc. You can test this by putting a color bound book or fabric covered furniture in a sunny window for a few months. You will start to see the color fade as the rays work on the book or furniture. Often women will say they never go out in the sun but their chest is permanently red and wrinkly, their hands look old which I usually categorize as "free-way" or "commuter" aging. A pulled down head visor in a vehicle does not protect your hands on the steering wheel or exposed chest driving into the sun. Car pooling, commuting or traveling congested areas even several times a week is enough to cause aging. When taking the train or plane is the sunlight on your hands or chest? Male skin is thicker "free-way" or "commuter" aging affects them mostly by more brown spots on the exposed side of the face. Living in a sun state or country, for example, Mexico or equator countries provide a constant sunny environment making a daily full spectrum sunblock necessary.
Body's Reaction to UVA
UVA shoots through the epidermis and disperses in the dermis the second layer of the skin. The dermis is called the "true skin" and stops gleefully renewing itself around the age of 28 years. Skin after this age is considered "mature skin". Damage incurred is not mended as well if at all, fair skin people look in the mirror and ask "What happened?". It is the aging process and like new paint on a car in a crowded parking lot years later does not look so great. The skin like new paint on a car has to be taken care of and protected. The dermis is composed of collagen, elastin , blood vessels, nerve endings and ground substances (glyco-amino-glycans, mucopoly-saccharides). It provides the firm youthful mattress for the skin. Prolonged exposure of UVA cracks and shrinks the collagen and elastin. The size of the layer becomes smaller so the epidermis (top layer) starts to droop or hang off the body. Blood vessels become permanently dilated giving a constant red flush to the skin. The few remaining melanocyte cells that are scattered in the dermis either die making a white spot or become over active leaving a brown spot. There are no lasers or procedure available at the moment that guarantees the removal of these brown spots and some procedures make them worse. The water binding ground substances are less and ineffective making the skin dry. In the end over exposure to this ray can put you in the dermatologist or plastic surgeon's office faster than any other aggravator. Not to mention the reported deaths from radiation poisoning from tanning beds.
Sunlight regulates our biological clock and provides essential vitamin D. Common sense should be used in regulating the amount of time in the sun.
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