Sunday, May 04, 2008

Sunscreen 101

Now that I've harped on you being safe in the sun, I want to help answer some questions about sunscreen. I've scoured the web and found some really useful info to help you out.

How do I choose a sunscreen? Look for a product with a minimum SPF of 15 to protect against the sun's ultraviolet B (UVB), or burning, rays. The product should also contain ingredients that protect against ultraviolet A (UVA) rays which penetrate more deeply into the skin and are responsi­ble for premature aging and contribute to the development of skin cancer. Sunscreens that are labelled "broad-­ spectrum" help protect against both.

What is an SPF? All sunscreens are labelled with a sun protection factor (SPF) number. This relates to the amount of time it takes for your skin to burn without any protection and how long it would take if you used the appro­priate amount of sunscreen. An SPF 15 product filters out more than 93% of the UVB in sunlight allowing about 7% penetra­tion. An SPF 30 filters out 97% and allows 3% penetration. So an SPF of 30 is not twice as effective as a 15, but rather it blocks out about twice as much of the penetra­tion. Stated differently it allows only half the UV penetration.

Are there sunscreens for use during sports? Yes, some sunscreens are labelled as sports products and are suitable because they have been specially formulated to stay on the skin during sports.

Are there any sunscreens for sensitive skin? If you have sensitive skin, try a small amount of the product on your arm and check for any reaction up to 48 hours later. People allergic or intolerant to the chemicals in sunscreens should look for products labelled "chemical-free". These usually contain ingre­dients such as titanium dioxide and zinc oxide that reflect rather than absorb the sun's rays and are much less likely to cause a reaction.

When should I put on sunscreen? You should apply sunscreen generously and evenly about 30 minutes before sun exposure to allow the active ingredients to bond to your skin. A second application 20 minutes later will maximize the pro­tection from your sunscreen. Reapply every two hours or after swimming or sweating a lot.

Does a product still work after its expiration date? Sunscreens contain chemicals that eventually break down, compromising the effectiveness of the product, so you should not use a sunscreen after its expiry date. Also, sunscreens are often kept in hot temperatures - in the glove compartment of a car or in a beach bag - conditions which accelerate the deterioration of the product.

How do I protect my lips? Use a minimum SPF 15 lip balm. There are a variety to choose from. Don't forget to reapply every hour.

When do I need to protect myself from the sun? You should be protected from 10 am to 4 pm from late spring to early fall and during winter if you are involved in outdoor activities. The sun's rays are strongest around midday, so try to avoid exposure around that time. The sun is harsher the closer you are located to the equator and at higher altitudes where the thinner atmos­phere blocks fewer of the sun's rays. The damaging effects of direct exposure to the sun can be increased if there is reflection from snow, water and light colored sand. Snow reflects up to 80 per cent of the sun's rays - so you could be getting a double dose of radiation when involved in winter sports.

Am I still at risk even if I have dark skin? Yes. Although people with light skin are at the highest risk for skin cancer, people with darker skin are also at risk. Plus, people with darker skin are also affected by the aging effects of the sun, as are lighter-skinned people. Everyone is at risk for eye damage from too much UV exposure, including snow blindness, cataracts, and retinal damage.

Can I get a sunburn while wearing sunscreen? Sunscreens are a temporary defense against UV radiation. You should first make sure that you have applied enough sunscreen. Studies have shown that most people underestimate the amount of sunscreen that they need. Next, think about your sunscreen’s “Sun Protection Factor,” or SPF. A sunscreen’s SPF tells you how long a sunscreen will be protective. Let’s say on a spring day on the mountain, your skin sunburns in 20 minutes. If you use a sunscreen with an SPF 15, you will get 20 x 15 = 300 minutes (5 hours) of protection. But if you stay outside for over 5 hours, your skin will sunburn even though you applied sunscreen. Also, remember to reapply your sunscreen throughout the day as it can wear off with wind and sweat. Knowing how to correctly choose and use sunscreen will help you prevent a sunburn from the sun’s harmful UV rays.

Is sunscreen all I have to wear to protect myself? No. You should use sunscreen in addition to practicing other sun safe behaviors. The best protection (though not always a possible solution) is to reduce the time you spend in the sun by seeking shade or staying indoors, especially at midday. Also, wear clothing that covers up a lot of your skin and choose a wide-brimmed hat rather than a ski or baseball cap. Finally, apply a broad-spectrum, waterproof sunscreen on all skin still exposed to the sun.

Does sunscreen block Vitamin D production? The sun helps the body produce its own Vitamin D, in addition to getting some of this nutrient from your diet. Vitamin D is needed for good health and the development and maintenance of strong, healthy bones. Although sunscreen keeps UV rays from being absorbed by your skin, don’t worry – eating a balanced diet provides enough Vitamin D to keep you healthy. Plus, the amount of exposure your hands get in just five minutes while walking from your car to the store, work, or other area is enough to stimulate plenty of Vitamin D production.

And now you know...and knowing is half the battle!!


Anonymous said...

I suggest you scour the internet some more.

Here is something you might wish to consider:

Lydia said...

I love when people post anonymously.

I am all for getting both sides of the story out there. I, for one, would love to know who is behind, the site you mention, anon. All is see is a bunch of forums, and forums do not necessarily contain truthful information.

I know the tanning industry, much like the tobacco industry, is trying hard to deny any link between their product and cancer. Sorry, but I just don't buy it. Skin cancer is real. Exposure to UV rays can cause it. Being SMART about exposure is essential. Pretending there is no risk in lying in a tanning bed or soaking up the sun? That will get you nowhere and could potentially result in tragedy.

Common sense needs to prevail. But like I said, thanks for your anonymous comment.

John said...

Hi Lydia, me again, it's easier to post anonymously rather than siging up to 23534578 different services and blogs. However I have used my name this time, hope that helps.

In any case, you too need to do some more reading, IMO :)

Unlike other sources who attempt to scare you out of the sun by telling us about all the studies, but never provide a source, sites like have acutally been compiling info and listing the sources of the studies and articles as they relate to moderate UV exposure, tanning and Vitamin D.

"Skin cancer is real." Yes it is, but from what source, the 25 years of being told to slather on toxins in the form of sunscreens perhaps?

"Being SMART about exposure is essential." Yes, moderation is always the key.

"Pretending there is no risk in lying in a tanning bed or soaking up the sun? " There is a risk to everything we do everyday. Everytime you put food in your mouth there is a risk you will choke and die, should we all stop eating?


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