Wednesday, November 11, 2009

Does an SPF30 Sunscreen Mean Twice the Sun Protection as SPF15

The weather is beginning to cool down but the sunrise happens every morning anyway. Sadly, many of us think that sun protection is not important during the winter time. Skin cancer occurs more frequently than all other cancers combined. In the U.S. alone, there will be about 1,000,000 new cases of skin cancer this year. Importantly, the rate of skin cancer is increasing rapidly for reasons that are not entirely clear but surely have something to do with sun exposure. And as a result USA has the highest rate of skin cancer in the world. It’s frightening to see that more and more Americans are treated for skin cancers every year.

We all need to be extra vigilant with protecting our skin from the sun when participating in outdoor activities. This includes wearing protective clothing, slapping on a hat and applying the right sunscreen. When shopping for a sunscreen, we are normally faced with selecting between:

1. SPF15 sunscreen

2. SPF30 sunscreen

3. SPF50 sunscreen

But what exactly does the sun protection factor (SPF) mean???

SPF (Sun Protection Factor) is a rating system for sun protection. The SPF of a product can be low or high – anywhere from SPF 2 to SPF 60. The number is a measure of how much longer you can stay in the sun without burning, as compared to how long you can stay in the sun without burning while wearing no protection. Example: Start with the amount of time in the sun that it takes to cause a burn. Say that your skin normally begins to turn red after 10 minutes of unprotected sun exposure. If you use a product rated SPF 2, your skin would not begin to turn red for twice that time: 20 minutes. If you use a sun product rated SPF 25, you could stay in the sun for 250 minutes, a little over 4 hours (25 x 10 minutes) before your skin would start to turn red.

The most popular levels are SPF 15 and SPF 30. But does an SPF30 sunscreen mean twice the protection as an SPF15 sunscreen?

The answer is NO.

In a controlled laboratory, SPF30 sunscreen allows transmission of 3.4% of UV radiation. In other words, it blocks 96.6 percent of the UV radiation. On the other hand, an SPF15 sunscreen will block out approximately 93% of the UV radiation. These percentages are just a guide and in reality away from a controlled laboratory test, these figures will vary according to your skin type, the weather and the time of day.

As a general guideline, if you have fair skin, it is best to go for a sunscreen with SPF30 or higher broad spectrum water resistant sun protection. Make sure to use a broad spectrum sunscreen to block out both the harmful UVA and UVB rays. If participating in vigorous outdoor activities, Reapply every 2 hours.

What else should I keep in mind when using sun protection?

Sun protection is especially important when the sun’s rays are more direct – during peak UV hours, or when you are closer to the equator. In addition, you can avoid sun exposure when the rays are strongest (generally between 10AM – 3PM), and wear hats and clothing to filter out UV rays. It’s also important to remember to apply sun protection products 15 to 30 minutes BEFORE sun exposure – and to reapply them frequently, especially after swimming or perspiring, or toweling off. Usually one ounce of sunscreen, enough to fill a shot glass, is enough to cover most exposed skin.

Sun protection isn’t just for days at the beach, though. Your face and hands especially are exposed to UV rays when you’re outside, even on cloudy days. The window glass of your car blocks UVB rays, the rays that burn your skin – but glass doesn’t block UVA rays, the ones that do the deepest tissue damage. So wearing a little sun protection when you’re driving is a good idea.

What’s the best product for me?

Environmental Working Group or Skin Deep conducted a research and put in place a list of the safest SPF products they recommend. It can be found here. There are a few of wonderful products, but making your choice insure that you use product with both UVA and UVB protection that's achieved with Titanium Dioxide and Zinc Oxide together. That's what makes it Broad Spectrum Sunscreen.

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