Ultraviolet(UV) light, what is it? First and foremost, it is a type of electromagnetic radiation with enough energy to break chemical bonds of all kinds, including living tissue. Most of the ultraviolet light falls into wavelengths between visible light and X-ray, and it reaches the earth in wavelengths between 400 nanometers to about 180 nanometers. UVA, or near UV, has a wavelength of 315 - 400 nm, and UVB, or middle UV, has a wavelength between 280 - 315 nm. There is even a third UV band called UVC, or far UV, which is between 180 - 280 nm. UVB penetrates the top layer of the skin (the epidermis), and a suntan is a reaction to exposure to harmful UVB rays. UVA penetrates deeper and can injure living tissue, such as collagen and elastin. I think of it this way – UVA, A for aging, UVB, B for burning.
Is there such a thing as a healthy tan?
“But I always feel healthier when I have a tan!” That’s probably because your body manufactured a good dose of Vitamin D along the way. Vitamin D is made from cholesterol when your skin is exposed to sunlight. Sun exposure is the best way to get Vitamin D because it is difficult to get Vitamin D in substantial amounts in food. But a tan is a sign of injury afterthe damage has been done. A suntan results from the body's natural defense mechanism kicking in. Melanin, a pigment produced by cells in the skin, absorbs UV light and dissipates it as heat. When the body senses sun damage, it sends melanin into the surrounding cells to help protect them from sustaining more damage, and this pigment causes the skin to darken and appear as a tan.
Clearly, we all know when we’ve had “too much sun,” but the insidious part of this is that radiation is bioaccumulative. With repeat exposure, we increase the damaging effect to our skin. For those of us who drive, have you ever noticed that you have more damage on your left side than your right? We’re exposed to UV light from many sources, including our TVs and phones! And I won’t even go into the dangers of tanning booths.
How do I get vitamin D without sun damage?
So, what are the best ways to get Vitamin D and protect this fragile covering that is our face to the world?
Well, obviously staying out of the sun helps, although UV rays penetrate glass and reflect off of surfaces, so it’s impossible to avoid altogether. Wearing hats does help, as does sun-protective clothing when we’re outdoors. In the end, though, it’s sunscreens that are the best sunprotection for our faces and hands that are always exposed to UV light.
0 Comments:
Post a Comment