SPF - What It Is, What It Does.
The Sun Protective Factor You And Your Family Need
SPF stands for Sun Protective Factor. What the heck is that? The official explanation is that it is a number based on the minimal erythema dose (MED) multiplied by the SPF number. The MED number is the amount of sun exposure required to produce mild redness in the "average" skin. (more about what's average, later!).
Multiply your SPF number x 10 to find out how many minutes you can stay out in the sun without burning.
If it takes 10 minutes to produce redness in the "average" skin (the MED number) and the SPF of your product is 15, It takes 10 x 15 = 150 minutes of sun exposure before your skin begins to show redness.
The SPF measurement guards against UVB exposure, but not always for UVA.
You don't know when you're getting too much UVA rays because you don't see redness on your skin.
UVA rays are sneakier. They penetrate and do their worst under the epidermis. SPF numbers are important to get a general sense of how much protection you're getting but they are not the whole story.
Lots 0f Melanin Won't Always Protect You
Darker skins have lots more natural melanin in them - the determinant of pigment - and are more resistant to burning in general. But be wary anyway. You could be burning even though you don't see any visible redness. Palms and the soles of feet are vulnerable to sun damage too.
Tan Today...Burn Tomorrow?
You may find yourself burning faster on the beach in high summer or the slopes in high winter than you will in your own backyard.
Rx For Sun Damage - Sun And Some Medicine Don't Mix
And, finally, in this day of complex medications, some people may find themselves inexplicably reddening faster under the sun than they ever did before. Prime example: users of Retin A are routinely warned to avoid sun exposure because their skin becomes extra photo-sensitive and easily sunburned.
Customize Your Protection
Have a few different levels of SPF protection on hand and adjust them to how your skin seems to be reacting now - not how it did a few years ago or even last summer. You change and so does your skin.
Don't Wash Your Protection Away
Look for a unblock or screen that is not water soluble. Even moderate perspiration can wash away protection, not to mention swimming and water sports. However, the newest products are water-resistant or even waterproof to allow for long term, continuous water exposure without washing off which is great news for swimmers and people who don't want to reapply sunblock or screen after every dip in the ocean or pool.
Sunscreens - The Future Is Bright
New technology may include:
• Longer lasting broader range sunscreens
• Using the body's own melanin to block burning
• Vitamins A, C, E, to help protect and heal
• Anti-aging ingredients that destroy free radicals - the unstable molecules released by our skin when they're hit by sunlight and pollutants, that lead to wrinkles and aging