15, 30, 45, Oh My: Decoding SPF Numbers

| Living

Understanding the SPF, or sun protection factor, for your go-to sunscreen can get overwhelming pretty fast. As you're packing your pool bag, making room for a variety of different sun lotions can be difficult and unnecessary! If you're ready to lighten your load this summer, then take a look below at what the SPF number is actually telling you!

Self tanning

If we're getting technical, then the SPF is a reference to the theoretical amount of time you can spend in the sun without getting burned. For instance, it typically takes most people about 30 minutes in moderate sunlight to start burning. So, hypothetically, 30 minutes x 15 SPF sunscreen equals 450 minutes of protection before you begin burning.

It is estimated that a sunscreen with an SPF of 15 blocks out about 93 percent of UVB (or short wave) rays. The higher the SPF, the more rays you will block out. For instance, if you bump up that SPF to 30, experts claim that you can block out around 97 percent of UVB rays, and so on. Also, most SPF lotions can only protect us against UVB rays. It is unknown whether sunscreen offers adequate protection against UVA (or long wave) rays. UVA rays can potentially travel deeper into our skin and cause more damage, so regardless of what SPF you choose to stick with, make sure that you are investing in lotion that also offers protection from these damaging rays too! Remember, though, that this is all mostly theoretical. The truth isn't quite as simple.

So what exactly is the truth? Well, that can get a bit tricky. There are a lot of factors that can affect the strength and endurance of your sunscreen. Taking a dip in the pool, even just to cool off, can reduce the effectiveness of your lotion. Sweat, too, can be an obstacle to even the strongest sunscreen. If you fail to apply the lotion evenly, you may wind up with a splotchy tan line, and if you don't reapply regularly, your skin may be exposed to the elements!


>> Read more: Fun Without the Sun: Pros and Cons of Spray Tanning

Then, there are some factors that are just out of our control. For example, people with fairer skin, or those who have a history of skin cancer in their families, are especially prone to sunburns and are at a higher risk if they use lower SPF lotions. Also, certain medications (especially antibiotics) can actually increase your sensitivity to the sun, so make sure you lather up before you hit the beach! Even if you are just planning on spending an afternoon gardening, make sure that you take the necessary precautions to protect your skin. There are several tips out there to help you find the right kind of lotion for you and your family. Here are some general recommendations:

  • Choose the correct sunscreen. It might be tempting to go with the brand you used when you were a kid, but there are now sunscreens out there that offer protection against both UVB and UVA rays. Also, we recommend sticking with an SPF of 15 or higher.
  • Reapply at least every 90 minutes. Even if it means dragging the kids out of the pool and suffering through five minutes of whining, make sure you are reapplying regularly. Remember that elements like water and sweat decrease the stamina of even the strongest sunscreen!
  • Keep up with skin checks. Regardless of whether or not you apply your sunscreen liberally, it is essential that you keep an eye out for new moles or changes in your skin. Skin cancer is nothing to laugh at; make sure that you and your family stay safe this summer!

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For more information on sunscreen SPF and UVB and UVA rays, check out our sources here: One Medical, Skin Cancer Foundation, Guardian Liberty Voice.