Ask the Coach: SPF and Shirts

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Wearable UV protection

Photo by Pedro Semitiel/Creative Commons 2.0

I burn easily and run in a sun-abundant state.  Do the high-SPF-rating shirts really offer more protection than less expensive shirts made of similar materials?
—Gordon Sargent, Tijeras, NM

Every shirt in your drawer provides some protection from the sun’s harmful rays. “Each fabric is different. Some are protective by the nature of the weave; other fabrics require a treatment,” says Jenn Zollars, Senior Product Manager for Mountain Hardwear. The decision to purchase a more expensive shirt because it has a UPF rating is an individual one, and one that fair-skinned runners should consider.

It’s not likely that you are damaging your skin if you don’t have a visible burn, but even mild reddening can kill the top layer of skin. Darker shirts provide more protection than lighter-colored ones, because they disrupt the UV rays more. The best way to choose a shirt is to hold your options up to the sun and see which garment lets less sun through.

Similar to the rating system for sunscreen, the sun-protection rating system used for clothing is called ultraviolet-protection factor, or UPF. This testing and rating system was developed in Australia, where skin damage is a widespread concern. A UPF rating of 30 indicates the fabric of a garment will allow only 1/30th (roughly three percent) of available UV radiation to pass through it. Like sunscreen, the higher number affords more protection; however, there is no labeling above 50, as any fabric that allows two-percent or less UV transmission is simply labeled UPF 50+.

SPF-rated clothing is, of course, best for runners with sun-sensitive skin living in high-UV environments.


This article originally appeared in our September 2014 issue.

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