Understanding Sunscreen Strength
By Sara Butler
Summer is here, and with it comes fun in the sun! Everyone knows if you’re going to be out in the sun for extended periods you need to wear sunscreen to protect your skin. You may think the higher the number on the sunscreen bottle the better it will be for you, but there are some guidelines to help you find the right strength of sunscreen. Here’s what you need to know!
What the Numbers Mean
When you see “SPF” on a bottle of sunscreen, it stands for “sun protection factor.” The SPF helps to shield your skin from UVB rays, which are the rays that actually penetrate the surface of your skin and cause sunburn. UVA rays, on the other hand, can penetrate your skin deeper than UVB rays can, so it’s important to look for a sunscreen that is full spectrum, meaning it protects against UVB and UVA rays.
The Skin Cancer Foundation says in 20 minutes the rays from the sun can burn your skin. The number following the SPF on your sunscreen bottle determines the time, multiplied by 20, the sunscreen can protect your skin from burning. So, if you wear SPF 30 sunscreen, it can theoretically protect your skin for 10 hours.
The problem is you sweat and swim when you wear sunscreen, and that diminishes the amount of time a sunscreen will actually protect you from the harmful rays of the sun.
Figure Out the Strength
An easier way to determine what sunscreen you should be using is to figure out the strength of a sunscreen. Read the bottles carefully to see to what extent the strength protects against UVA and UVB rays. SPF 15 is just fine for most people to use, as it protects against up to 93 percent of UVB rays. SPF 30 may protect against 97 percent, so it’s not that big of a difference.
The only time it really makes a huge difference is if you are a fair-skinned person who burns easily. If this is you, a higher SPF will do the job – just make sure it’s a broad spectrum that protects against UVA rays too.
Where You Apply It
Another fact that influences what strength of sunscreen you need is where you’re going to apply it. The face and the chest will have the most exposure to the sun, so you may want to bump up to an SPF 30 sunscreen to protect the skin there. In general, if you’re unsure what strength of sunscreen to use, you should go for the higher number.