Here Comes The Sun!

May 16 , 2005

by Laura Dolson

By now, you probably think you know what there is to know about the dangers of sun and sun protection. But did you know…?

- No sunscreen offers complete protection from the sun's damaging rays. - Most sunscreens offer little or no protection from most of the rays that cause the most deadly kind of cancer. - Most of a person's lifetime sun exposure takes place by their early 20's. - Teens, who are in their peak sun exposure years, tend to use sun protection the least of all age groups. - Sun protection needs to be a multi-faceted program of reducing exposure to damage - no one method will completely protect you (except for staying out of the sun entirely). - Most people who use sunscreen do not use it in a way that offers the most protection.

Types of Ultraviolet Rays/Types of Skin Cancer

Ultraviolet rays are the damaging rays that come to us from the sun. Although sunlight has some good effects (such as producing vitamin D), ultraviolet rays cause some damage at even small doses. There are essentially two kinds of ultraviolet rays that make it to the earth's surface. We can think of them as two bandwidths, or ranges of wavelengths. (You will notice that the two wavelength ranges shade are continuous - both kinds really cause all kinds of damage. We are talking about "primary responsibility"):

Ultraviolet B (UVB) Radiation - 290-320 nanometers - This type of radiation is responsible for most sunburn, and the two most common types of skin cancer - basal and squamous cell cancers.

Ultraviolet A (UVA) Radiation - 320-400 nanometers - This type of radiation is responsible for the less-common, but more-deadly type of skin cancer: malignant melanoma. It penetrates deeper into the skin and is more able to break down connective tissue as well. It also varies less over the course of the day and year than UVB light. Also, unlike UVB, window glass does not protect against UVA light.

Both Types - cause other skin damage (premature aging and wrinkling, easy bruising), eye damage (including cataracts) and decreased immune function.

Clouds - Clouds only screen out some of the ultraviolet radiation the sun produces. A light cloud layer can let up to 80% of the UV light through, and even heavy clouds let some through.

Snow, Sand, and Water - reflect the sun's rays, intensifying their effects.

Tanning Salons - Don't believe them if they tell you that tanning beds won't damage your skin. They contain lots of UVA light.

How Can We Avoid Sun Damage?

First Line of Defense - Stay Indoors During Peak Hours

We've all heard it - the hours between 10 and 3 are the most dangerous for sun exposure. This is especially true for UVB light, although UVA light also peaks at this time. A rule of thumb is to stay out of the sun when your shadow is shorter than you are.

The UV Index Can Give You More Info - (Plug in your town or zip code)

Second Line of Defense - Protective Clothing

The Australians have learned a valuable lesson about protective clothing, and it has helped them to reduce the worst skin cancer rates in the world. Protective clothing is essential. This is the best way to avoid UVA rays when outside. However, regular clothing only blocks out some rays. The best clothing for sun protection:

1) Covers You - Wear loose-fitting long sleeves and pants, and hats that shade your neck as well as your face.
2) Is Tightly Woven - Hold the fabric up to the light. The less light you can see coming through, the more protective it is. A standard T-shirt provides only 6-8 SPF. Dark colors sometimes provide more protection.
3) Is Dry - wet clothes are much less protective against UV light.
4) Includes Sunglasses - Wrap-around sunglasses that protect against UVA and UVB are best. "Polarized" sunglasses cut down on the glare, but don't protect the eyes.

Also,
5) Consider Specially-Made Sun Protective Clothing - If you can't avoid being in the sun for long periods, consider getting clothing made from special sun-protective fabrics. These are more expensive, but are made to give extra protection, and are given "UPF" (Ultraviolet Protection Factor) ratings. Ratings Info http://www.melanomafoundation.org/prevention/clothing.htm

Third Line of Defense - Sunscreen

You may be surprised to see sunscreen listed third. This is for three reasons:

1) Sunscreen can give a false sense of security. - People who use sunscreen may stay in the sun longer. This is not the idea of sunscreen, which is just to protect you while you are in the sun. No sunscreen gives complete protection.
2) Most people don't use sunscreen correctly. - You need to use a lot of it, and you need to apply it often. Your skin should look white when it first goes on (it sinks in after 20-30 minutes). An average adult wearing a bathing suit should use about an ounce per application. Reapply every two hours - more often if swimming or sweating, even if it's waterproof.
3) Sunscreen is especially bad at protecting from UVA radiation. The SPF number on sunscreen is only for burn protection, which comes from UVB radiation. This is probably why some studies have shown that sunscreen users have a higher rate of melanoma - they stay in the sun longer without UVA protection. If there are any UVA-protecting ingredients in a particular sunscreen, the label will say it has UVA protection, BUT:
a) Some of the most common UVA-protecting ingredients only protect against a part of the UVA spectrum. For example, oxybenzone, often seen in sunscreens, only protects in the UVA range of 320-340 - most of its protection is in the UVB range.
b) There are not yet any standards for knowing how much UVA protection you are getting from sunscreen. An ingredient may be listed, but that doesn't tell you how much there is in the product.
c) There are only three approved ingredients that protect against the whole UVA spectrum. They are: avobenzone (also called Parsol 1781 and Butyl methoxydibenzoylmethane), zinc oxide, and titanium dioxide.

Also, check the expiration date! I just found a bottle in our house which expired over two years ago. Needless to say, I threw it away.

Question for Discussion: Why do teens use sunscreen less? What would help you to use sunscreen more consistently?

Bonus Link: Pictures of my friend's mom when in treatment for skin cancer (warning, the pictures are pretty graphic)