Ultraviolet or UV rays are the invisible rays of light from the sun. Overexposure to these rays can cause skin damage like sunburn and accelerated aging; it also increases the risk of developing skin cancer, which is the most common type of cancer in the U.S. These risks are increased for people with fair skin, children, and people living at high altitudes. While all clothing protects the skin from the sun to some extent, some types of clothing are better than others.

For the best protection, choose clothing that is labeled with an ultraviolet protective factor, or UPF. Similar to the sun protective factor (SPF) ratings you see on bottles of sunscreen, the UPF is a rating system specifically for clothing that indicates how well a fabric protects the skin. The higher the number, the more protection the clothing offers. UPF considers both ultraviolet A rays, which can affect the skin at any time during daylight and can penetrate the skin deeply, and the ultraviolet B rays, which cause sunburn. Both types of rays contribute to signs of aging and a risk of developing skin cancer.

A UPF rating of 15-24 is considered “good,” 25-39 is “very good,” and above 40 is “excellent.” If a piece of clothing has a UPF rating of 25, that means that only 1/25 of the possible UV light can pass through the fabric to your skin. A rating of 50 allows only 1/50 of UV rays to pass through. The rating system was first developed in Australia, but now is a standard practice among clothing manufacturers.

Some of the factors that affect the UPF rating of a piece of clothing include the construction type, the fabric, the color. Clothing made with a very tight weave, so that there is little space between fibers for sun light to pass, is more protective than a looser weave. Synthetic fabrics, like polyester and acrylic, are more protective than cotton and linen. The color of the fabric is also a factor; dark or bright colors are more protective than light, pale colors. To learn more about sun protective clothing, visit heamotivation.com.