What SPF Should You be Wearing?

By Dr. Jack Cornwell, medical director, CareWell Urgent Care

When summer rolls around in New England, we tend to soak up as much sun as we can for as long as possible. When spending so much time outside it is important to remember to wear sunscreen, even if it’s not the hottest or sunniest day. Sunscreen can help protect you from harmful ultraviolet rays as well as prevent sun burns, aging skin and skin cancer. Yet as you scan the shelves filled with various sun protection factor (SPF) ratings, it may be confusing to decide which one is right for you. Can a 100+ SPF actually protect you from the sun more than one with an SPF of 30?

Recommendation

SPF is a measure of how well a sunscreen will protect skin from UVB rays, which can cause sunburns, but not UVA rays, which are more closely associated with deeper skin damage. The SPF rating measures the length of time it would take your skin to burn if you were not wearing sunscreen as opposed to the time it would take with sunscreen applied. The American Academy of Dermatology recommends using sunscreen that is broad-spectrum, water resistant and has an SPF of 30 or higher. Broad spectrum sunscreen will protect against both UVB and UVA rays. Since no sunscreen can block 100% of the sun’s rays, you may want to wear an SPF higher than 30 depending on your skin tone and type. Furthermore, dermatologists typically favor lotion-based sunscreens compared to aerosol sprays. Spray-on sunscreen isn’t always applied as thoroughly as it should be and therefore may not provide the full SPF listed on the label.

Reapplication

Though higher-number SPFs may block slightly more UV rays, it is important to remember that they do not last longer than low-number SPFs, both will last the same amount of time. For this reason, sunscreen should be reapplied to areas exposed to the sun approximately every two hours. Apply more often if you are swimming or sweating, even if the sunscreen you’re wearing is water resistant.

Risks

Spending any amount of time in the sun can increase your risk of skin damage, particularly between the times of 10 a.m. and 2 p.m. when UV rays are at their strongest. If left unprotected and exposed to the sun, skin damage can begin in as little as 15 minutes, but it can take up to 12 hours for skin to show the full effects. Applying sunscreen can help relieve these risks, but only when used effectively. Remember that sunscreen will not protect you from all types of sun damage and there are other precautions you should take.

If you are suffering from a bad sunburn, visit a local urgent care center. Providers can help sooth your skin so you’ll be back to soaking up the sun (safely) in no time.