ABCs of SPFs & UVB/As


Fri April 24, 2015 11:10am

By now you know that you shouldn’t frolic outdoors for a prolonged period of time without covering yourself in sunscreen. However, a trip to the drug store will reveal a variety of choices that might leave you feeling confused and convinced to stay indoors.
But a quick refresher course will remind you of what it is you’re protecting yourself from and what you should look for in protection.
The sun shines — even when obscured by clouds — and the sunlight that brightens our lives is made up, in part, of waves, long ones and short ones.
Ultraviolet radiation is part of the light spectrum that travels from the sun to the Earth. In general, UV radiation can produce genetic mutations that can lead to skin cancer. UV radiation is considered one of the causes of nonmelanoma skin cancer and squanamous cell carcinoma, which, combined, afflict 1.25 million Americans annually.
There are three types of UV radiation waves:
UVA waves — These are the long waves of radiation and are more closely associated with aging and wrinkling human skin, penetrating deeper into the epidermis.
UVB waves — These shorter waves of radiation are generally associated with tans and sunburns. That “healthy” darkening you get when you sunbathe is actually the body’s way of protecting itself from absorbing more damage from cancer-causing waves. UVB rays don’t go as deeply into the skin; the most significant amount of UVB rays are absorbed between 10 a.m. and 4 p.m.
UVC waves — These are short waves of radiation and are mostly absorbed by the Earth’s atmosphere.
Perhaps the most important thing to know about sun protection factor is that it is not a primary indication of an amount of protection from UVA or UVB rays so much as it is an indication of time.
For example, if your skin starts to burn after spending 10 minutes in the sun, using a sunblock with an SPF factor of 15 will allow you to stay in the sun for 150 minutes before you start burning.
Ideally you should apply about one ounce of sunscreen over the parts of your body that will be exposed to the sun 30 minutes prior to going outdoors and reapply the same amount every two hours until you come back indoors.