article about UVA and UVB sunlight

Ultraviolet sunlight and UV400 protective lenses – what you should know

Vitamin D

Outdoor activities in the summer or winter are not only fun, but they are very healthy too. Cold air contains more oxygen and working out outdoors, is generally healthier than working out indoors. But by being outside you are exposed to Ultraviolet radiation from the sun, which can be both positive and negative.

The positive part is that your body creates vitamin D when it is exposed to sunlight. “A bit of sunshine can do someone good” – it is in fact the creation of vitamin D that does one good. Vitamin D is good for strong bones, less depression and even has anti-cancer effects. Therefore it is important to expose yourself regularly to sunlight.

The negative side of being in the sun is that you are exposed to ultraviolet radiation. Overexposure to ultraviolet light, can burn your skin and damage your eyes. Even when the sun is not brightly shining or it is completely overcast, you can still get sunburned and your eyes are still sensitive to UVA and UVB radiation.

What is the difference between UVA and UVB?

UVA is short for “long wave ultraviolet A” and UVB is short for “short wave ultraviolet B”. Basically what that means is that the frequency of the radiation either has long or short wavelengths. UVA and UVB have different effects on humans. UVA rays make you have older skin, where as UVB burns your skin (creates the redness of a sunburn). Also, UVA goes through glass easily, where as UVB doesn’t.

Why UV400?

Because ultraviolet radiation goes up to a wavelength of 400 nanometer. This means that if sunglasses are UV400 protective, that close to 100% of both UVA and UVB radiation is being blocked by the lenses and your eyes are therefore fully protected. GoWood sunglasses also have UV400 protective lenses.

Regular sunlight, compared to UVA and UVB
Image courtesy of

For more information about UVA and UVB and what the dangers can be, please visit who have a really interesting article about UVA and UVB and what it does to your body.