Effective Sun Protection: Sunscreen or UPF Clothing?
With the increasing risk of skin cancer, everyone needs protection from the sun. But what is the best way to stay safe outdoors?
What SPF and UPF Mean. Both SPF and UPF are measures of sun protection. SPF (Sun Protection Factor) reflects the amount of time it takes for sun-exposed skin to turn red. For example, if your skin normally starts to burn after 20 minutes in the sun, using a sunscreen with an SPF of 15 protects your skin for about 300 minutes, or 15 times longer.
It is important to note that SPF only measures protection against UVB rays, which are those that cause sunburn in addition to skin cancer. “Since UVA rays also cause photo-aging, skin cancer, and other sun-related skin conditions and are not filtered by the ozone or window glass, it is important to use a sunscreen that is labeled as “broad spectrum” or otherwise specifically states that it blocks both UVA and UVB rays,” notes Dr. Aron Gewirtzman, board certified dermatologist at Sanova Dermatology in Austin, Texas.
There is no specific metric on a sunscreen that will measure the degree of UVA protection like there is with UVB and SPF. Physical blockers such as zinc oxide or titanium dioxide block both UVA and UVB. UPF (Ultraviolet Protection Factor) measures the amount of the sun’s rays, both UVA and UVB, absorbed by a fabric. Some clothing receives a rating based on its fiber density and structure, while others are treated with a UV-absorbing colorless dye.
Sunscreen Benefits. Sunscreen, when used correctly, offers effective protection, with an SPF-15 sunscreen blocking about 93% of UVB rays and an SPF-50 keeping out 98%. “For the greatest protection, a sunscreen needs a minimum SPF of 15, must be used in the recommended amount, a shotglass full for exposed areas, and reapplied every two hours or sooner if swimming,” suggests Dr. Gewirtzman. Unfortunately most people use too little sunscreen, sometimes only one-quarter to one-half the recommended quantity, which greatly reduces the sunscreen’s potency. For this reason, most dermatologists recommend at least an SPF 30 sunscreen in order to ensure added protection even if not applied exactly as recommended. Swimming, sweating and simple time also dilute the sunscreen’s effectiveness and forgetting to reapply puts many people in danger of serious burns.
UPF Clothing Benefits. “Clothing acts as a physical barrier to the sun’s rays. Light-colored fabrics with open weaves do not offer much protection, though darker fabrics with a high thread count per inch are highly effective at blocking the sun’s rays,” Dr. Gewirtzman says. Clothes marked as “sun-protective” usually have a UPF of 50 or more. A fabric with a UPF of 50 lets through only 1/50th of the sun’s UV light, that is, it blocks 98% of harmful rays. To receive the Skin Cancer Foundation’s Seal of Recommendation, sun-protective clothing needs a minimum UPF rating of 30; the Foundation deems a rating of 30-49 as very good protection and a UPF-50 or higher as excellent. Most sun-protective clothing takes repeated washings without losing its effectiveness, though stretching and becoming wet do impact its efficacy. There are several manufacturers specializing in clothing that is sun-protective, lightweight, and fashionable. Rit Dyes also makes a laundry additive, Sun Guard, to treat regular clothing. The treatment increases the UPF of the fabric and lasts through about 20 washings.
Sunscreen + UPF Clothing = Best Protection. For the very best protection from harmful rays, wear UPF-rated clothing in the sun. Then apply sunscreen to exposed skin, starting about an inch under sleeves and pant legs and on all other uncovered areas, including the face and hands. Add a hat and UV-protection sunglasses to keep yourself safe in the sun.
To learn more about sun protection, contact our dermatologists today.