WORKOUT WEDNESDAY: What Does the SPF Number on Your Sunscreen Actually Mean?


This blog post was written by Emily Wheeler and is published as part of our blog exchange with Tar Heel Tone-Up.

This week, we’ve seen three 80º F days in a row and one incredible thunderstorm early Thursday morning! You know what that means: North Carolina is racing through spring into our unpredictable, hot, and randomly stormy summer weather!

With the reemergence of plenty of beautiful sun, it’s time to start stocking up on sunscreen again! When you’re standing there in an aisle of literally over a hundred different types of sunscreen, it’s difficult to know what all of the different claims on all of the different bottles actually means! Here are a few tips on how to understand what different sunscreen lingo means so that you’ll have an easier time deciding!

sunburned

“Sunburned” by Erin Stevenson O’Connor of Flickr Creative Commons

  • SPF stands for Sun Protection Factor. Theoretically, this number is supposed to mean that the sunscreen will protect your from burning that many times longer than you can normally stay out in the sun without protection before you begin to burn. Example: If I can only stay outside for 10 minutes without burning, SPF 30 sunscreen is theoretically supposed to keep me from burning for 300 minutes. I say theoretically because this would happen under perfect conditions. In real life conditions, if you’re sweating, swimming, or just moving around a lot in a way that might cause any friction against your skin from clothes, you’re losing sunscreen protection and it might not last for the entire 300 minutes. A good rule of thumb is to reapply every 2 hours no matter what the SPF says! SPF is not a measure of how well the sunscreen will protect you, but rather how long the protection will last under ideal conditions.

Fun fact: SPF ratings were introduced in 1962. Apparently, they were determined in the lab by gathering up 20 people with sensitive skin, measuring the amount of UV rays it took for them to burn without sunscreen, and then repeating the test with them wearing sunscreen. If that was really the case, there is no way that this process continues today because it would be considered unethical since even a single sunburn is known to increase your risk of skin cancer over your lifetime.

  • “Broad spectrum” indicates that the sunscreen is protective against both UVA and UVB rays. UVB rays cause the visible red sunburns, so all sunscreens contain UVB protection. However, UVA rays can cause dangerous skin damage that can lead to cancer and wrinkles, so you’ll want a sunscreen that protects against both! If the bottle doesn’t specifically say “broad spectrum” or UVA/UVB protection, you can probably assume that it only contains UVB protection and they don’t want you to notice.
  • Even if they do not specifically mention UVA or broad-spectrum protection, look for zinc oxide and titanium dioxide on the “active ingredients” list. These also indicate protection against UVA rays! These ingredients are also included in many “sensitive skin” sunscreens, yet they still cause skin reactions in some people. However, they are approved for safe use and sometimes it just takes multiple brand attempts to find a sunscreen that works best with your skin.
  • Most lab tests of sunscreen use a much greater amount than the typical sunscreen-wearing beach-goer wears! You should be using about an entire ounce of sunscreen every time you reapply, which could be up to 4 or more ounces a day! Don’t skimp and buy a single 8 oz. bottle of sunscreen and then head to the beach for a week; sunscreen is cheaper than cancer treatment!
  • If you have a family history of skin cancer or you take medications containing retinol (a form of vitamin A often used in acne medications), you are at an increased risk for skin cancer and adverse effects to sun exposure, such as excessive burning even with sunscreen use. Talk to your prescribing doctor about safe sun exposure and try to take advantage of trees and umbrellas for shade! (And of course, be especially obsessive about your sunscreen use and reapplication).
  • Ladies: don’t want to mess up your makeup by applying sunscreen over it at the beach? You can (1) apply sunscreen to your face and let it dry before you put on makeup, (2) choose a foundation, liquid or powder, that contains at least a 15 SPF sunscreen because many brands make these now, (3) buy a tinted sunscreen that essentially works like makeup when you put it on! These would be found in the make-up aisle rather than the sunscreen aisle and are sold under various brand names.
  • While you’re in that sunscreen aisle, don’t forget that your lips count as skin, too! Buy a tube of lip balm with sunscreen (such as Carmex) to protect your lips to keep them from getting irritated, peeling and cracking, and encouraging the appearance of fever blisters if you already get them occasionally.
  • Finally, don’t forget that your scalp counts as skin, as well! For men with short hair or women with part lines in their hair, you’ll need to protect your scalp from burning with a sprayable liquid scalp sunscreen (called “scalp-screen”) or a hat!
  • So you’re not planning on going to the beach? What about biking, walking outside, or sitting on the quad? If you’re going to be outside for more than ten minutes, you need sunscreen!

My family and friends always shake their heads or chuckle at me when I’ve spent a lot of time outside one day and I look down at the end of the day and say “Oh no! I’m getting tan lines!” In the U.S. today, media has encouraged the notion that tanned, bronze skin is beautiful skin, and many people see their tan lines as a small victory that has fulfilled their purpose of a day at the beach. I, on the other hand, see tanned skin as damaged skin (and the CDC and majority of dermatologists seem to agree with me these days.) I’ll continue to slather my high SPF sunscreen onto my fair, freckled skin every couple of hours because I like my skin the way it is and I would rather be fair-skinned and skin-cancer-and-wrinkle-free than tan and worried about the consequences that might come from my sun exposure later in life.

1966 Ad, Solarcaine Spray,

You know what else stops sunburn pain? Not getting sunburned.

Also, it’s important to remember that even if you have dark skin and you don’t feel like you have to worry about tan lines or sunburn, the UVA/UVB rays still have the same damaging effects on your skin over time as they do on people with lighter skin! This means that you should be wearing sunscreen no matter what your skin looks like!

My favorite is Neutrogena Ultra Sheer® Dry-Touch Broad Spectrum sunscreen; it doesn’t smell like much and it dries on your skin and doesn’t leave you feeling so icky and greasy! I also like the Neutrogena Clear Face Liquid Lotion Sunscreen to prevent clogged pores and breakouts and the Neutrogena Pure & Free® Baby Faces Ultra Gentle Broad Spectrum sunscreen because typically any brand of baby sunscreen tends to have a higher SPF and is well-suited for sensitive skin that might react to other types of sunscreen. (I’m not advertising, but as you may have already assumed, I’ve tried many different types of sunscreen and I’ve stuck with the Neutrogena line for a couple of years now because it’s always worked great for me!)

Sunscreen

“Sunscreen” by Joe Shlabotnik of Flickr Creative Commons

Disclaimer: Some sunscreens work great on some people’s skin and really irritate other people’s skin! What works for me might not work for you, so I suggest that you do what I did and buy small bottle of several different brands next time you go to the beach so that you can try them all out and decide which is your favorite! Once you decide, then you go to Sam’s, Costco, or Wal-Mart and stock up on that bulk sized discount! J

Sources:

Jeffries, Melissa.  “What do SPF numbers mean?”  16 August 2007.  HowStuffWorks.com.http://health.howstuffworks.com/skin-care/beauty/sun-care/spf.htm  09 April, 2015.

Tachibana, Chris. “Probing Question: What does the SPF rating of sunscreen mean?” 1 June 2010. Penn State News. http://news.psu.edu/story/141338/2010/06/01/research/probing-question-what-does-spf-rating-sunscreen-mean 09 April, 2015.

The Best Sun Protection Plan for Rain or Shine. 5 April 2011. One Life, Make it Count: Aging Well. http://www.onemedical.com/blog/live-well/spring-has-sprung-the-best-spf-protection-plan-for-rain-or-shine/ 09 April 2015.

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