The dark side of teenage tanning

May 2, 2005

Tanning: UVB can cause sunburns… Under your skin

The ultraviolet light from tanning bed mimics the sun in some ways. Typical bulbs emit a small portion of UVB rays and a larger amount of UVA rays, in roughly the same proportion as natural sunlight

UVB rays penetrate the top layer of skin and trigger cells to melanin. This takes a while which is why a new tan might not develop for hours or days after exposure. UVB is also responsible for most burns, particularly in the midday summer sun when the path to your nose is most directed.

The bulk of the light in a tanning bed – 95 percent or more – is made up of longer UVA rays, which penetrate deep into the skin. UVA rays help darken pigment, intensifying a tan.

“The whole reason we get a tan is to protect ourselves from further ultraviolet light,” said Dr. Amy Forman Taub, medical director of Advanced Dermatology in Lincolnshire. “It’s our body’s defense.”

In the 1980’s, some dermatologist believed UVA rays were safer because they didn’t cause sunburns. Now evidence has emerged that UVA rays, which shoot through clothing, hats and windows, actually cause more damage.

Constant exposure to UVA and UVB rays damages skin cells, causes DNA to mutate and impairs and body’s immune system. Repeated stimulation of the pigment-producing cells with ultraviolet light appears to lead to skin cancer years later.

“There’s been plenty of research, especially in the past five years, to show what we thought were safe rays, UVA, are probably a very important component of something that can lead to melanoma,” Taub said. “It actually damages the cells, and then it damages the repair mechanism for the cells.”