Clothes can protect your skin against the sun's harmful ultraviolet (UV) rays. But not all clothing is created equal. The tightness of the weave, the weight, type of fiber, color and amount of skin covered all affect the amount of protection they provide.
What a UPF Rating Really Means
UPF stands for Ultraviolet Protection Factor and indicates how much of the sun's UV radiation is absorbed. A fabric with a rating of 50 will allow only 1/50th of the sun's UV rays to pass through. This means the fabric will reduce your skin's UV radiation exposure significantly, because only 2 percent of the UV rays will get through.
What's the Difference between UPF and SPF?
SPF stands for Sun Protection Factor and is the rating you're familiar with for sunscreens and other sun-protective products. It measures the amount of time it takes for sun-exposed skin to redden, while UPF measures the amount of UV radiation that penetrates a fabric and reaches the skin.
Which Fabrics Are Best?
As a rule, light-colored, lightweight and loosely-woven fabrics do not offer much protection from the sun. That white T-shirt you slip on at the beach when you feel your skin burning provides only moderate protection from sunburn, with an average ultraviolet protection factor (UPF) of 7. At the other end of the spectrum, a long-sleeved dark denim shirt offers an estimated UPF of 1,700 - which amounts to a complete sun block. In general, clothing made of tightly-woven fabric best protects skin from the sun. The easiest way to test if a fabric can protect your skin is to hold it up to the light. If you can see through it, then UV radiation can penetrate it - and your skin.
The color of the fabric also plays a role. Darker-colored fabrics are more effective than lighter at blocking out the sun. For instance, the UPF of a green cotton T-shirt is 10 versus 7 for white cotton, and a thicker fabric such as velvet in black, blue or dark green has an approximate UPF of 50.
Fabric Content and the Wearer's Activity Make a Difference
What the clothing is made of matters. Fabrics such as unbleached cotton contain special pigments called lignins that act as UV absorbers. High-luster polyesters and even thin, satiny silk can be highly protective because they reflect radiation.
Even if the piece of clothing has a good UPF, what you do while wearing it can make a difference. If the fabric gets stretched, it will lose some of its protective ability, because the fabric becomes thinner and more transparent to light. And once it gets wet, it can lose up to 50 percent of its UPF. In Florida, it is a common practice for parents to put a white T-shirt on their children to protect them from the sun while swimming. But when that T-shirt gets wet, it provides a UPF of only 3.
Here are other factors:
Construction: Dense, tight construction (either weaves or knits) minimizes the spaces between yarns, which in turn minimizes the amount of UV light that can pass through. Some tightly constructed UPF-rated garments use vents to boost air circulation and help the wearer stay cool. Thicker fabrics also help reduce UV transmission.
Dyes: It is the specific type of dye (and the concentration in which it is used) that impacts a fabric's UV transmission, not its color. Some dyes deflect more UV radiation than others, and some absorb none at all—including black dyes. How can one know what kind of dyes are used in individual garments? The only tip-off is if the garment carries a UPF rating. Clothing engineered for UV protection may use high concentrations of premium dyes that disrupt UV light. Such dyes include "conjugated" molecules that disrupt UV radiation. The higher the concentration of such dyes, the darker the garment becomes. But ultimately color has no influence on UV rays. Note: Pigment-dyed fabrics, which include a resin that creates a powdery look and feel, get high marks for UV protection.
Stretch: If a garment is stretched 10% or more beyond its normal dimensions, spaces between yarns are widened and its effectiveness against UV light may be reduced up to 40%.
Wetness: A fabric's ability to disrupt UV radiation is usually reduced when wet, though the reasons why are not completely understood. Wetness may cause a 30% to 50% reduction in a fabric's UPF rating.
Condition: Worn or faded fabrics are less effective against UV light.
Wash Sun Protection Into your Clothes
A laundry additive, Sun Guard, contains the sunscreen Tinosorb. When added to a detergent, it increases the UPF of the clothing, and this protection lasts through 20 washings.
So, give your skin a little extra TLC while out on the course and make sure to wear something with enough protection to keep your skin happy and healthy! Click here to Shop our TOPS with SPF.