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UV rays and you

People who get a lot of exposure to ultraviolet (UV) rays are at greater risk for skin cancer. Sunlight is the main source of UV rays, but you don’t have to avoid the sun completely. And it would be unwise to stay inside if it would keep you from being active because physical activity is important for good health. But getting too much sun can be harmful. There are some steps you can take to limit your exposure to UV rays. Some people think about sun protection only when they spend a day at the lake, beach, or pool. But sun exposure adds up day after day and it happens every time you are in the sun.

An obvious, but very important, way to limit your exposure to UV light is to avoid being outdoors in direct sunlight too long. This is particularly important between the hours of 10AM and 4PM when UV light is strongest. If you are unsure how strong the sun’s rays are, use the shadow test; if your shadow is shorter than you are, the sun’s rays are the strongest and it’s important to protect yourself.

UV rays reach the ground all year, even on cloudy or hazy days, but the strength of UV rays can change based on the time of year and other factors. UV rays become more intense in the spring even before temperatures get warmer. People in some areas may get sunburned when the weather is still cool because they may not think about protecting themselves if it’s not hot out. Be especially careful on the beach or in areas with snow because sand, water and snow reflect sunlight, increasing the amount of UV radiation you get. UV rays can also reach below the water’s surface so you can still get a burn even if you’re in the water and feeling cool.

Some UV rays can also pass through windows. Typical car, home and office windows block most UVB rays, but a smaller portion of UVA rays, so even if you don’t feel you’re getting burned your skin may still get some damage. Tinted windows help block more UVA rays, but this depends on the type of tinting.

If you plan to be outdoors, you may want to check the UV Index for your area. The UV Index usually can be found in local newspapers, TV, radio, and online forecasts.

Protect your skin with clothing: When you are out in the sun, wear clothing to cover your skin. Clothes provide different levels of UV protection. Long-sleeved shirts, long pants or long skirts cover the most skin and are the most protective. Dark colours generally provide more protection than light colours. A tightly woven fabric protects better than loosely woven clothing. Dry fabric is generally more protective than wet fabric.

Be aware that covering up doesn’t block out all UV rays. If you can see light through a fabric, UV rays can get through, too. Many companies now make clothing that’s lightweight, comfortable and protects against UV exposure even when wet. It tends to be more tightly woven and some have special coatings to help absorb UV rays. These sun-protective clothes may have a label listing the UV protection factor (UPF) value (the level of protection the garment provides from the sun’s UV rays, on a scale from 15 to 50+). The higher the UPF, the higher the protection from UV rays.

Some products, which are used like laundry detergents in a washing machine, can increase the UPF value of clothes you already own. They add a layer of UV protection to your clothes without changing the colour or texture. This can be useful, but it’s not exactly clear how much it adds to protecting you from UV rays so it’s still important to follow the other steps listed here.

Use sunscreen: It’s important to know that sunscreen is just a filter; it does not block all UV rays. Sunscreen should not be used as a way to prolong your time in the sun. Even with proper sunscreen use, some UV rays still get through. Because of this, sunscreen should not be thought of as your first line of defence. Consider sunscreen as one part of your skin cancer protection plan, especially if staying in the shade and wearing protective clothing aren’t available as your first options.

Read the labels: Sunscreens with broad spectrum protection (against both UVA and UVB rays) and with sun protection factor (SPF) values of 30 or higher are recommended.

Sun protection factor (SPF): The SPF number is the level of protection the sunscreen provides against UVB rays, which are the main cause of sunburn. A higher SPF number means more UVB protection (although it says nothing about UVA protection). For example, when applying an SPF 30 sunscreen correctly, you get the equivalent of 1 minute of UVB rays for each 30 minutes you spend in the sun. So, one hour in the sun wearing SPF 30 sunscreen is the same as spending two minutes totally unprotected. People often do not apply enough sunscreen so they get less actual protection.

Sunscreens labelled with SPFs as high as 100+ are available. Higher numbers do mean more protection, but many people don’t understand the SPF scale. SPF 15 sunscreens filter out about 93% of UVB rays, while SPF 30 sunscreens filter out about 97%, SPF 50 sunscreens about 98%, and SPF 100 about 99%. The higher you go, the smaller the difference becomes. No sunscreen protects you completely.

Sunscreens with an SPF lower than 15 must now include a warning on the label stating that the product has been shown only to help prevent sunburn, not skin cancer or early skin aging.

Broad spectrum sunscreen: Sunscreen products can only be labelled “broad spectrum” if they have been tested and shown to protect against both UVA and UVB rays. Some of the chemicals in sunscreens that help protect against UVA rays include avobenzone (Parsol 1789), ecamsule, zinc oxide and titanium dioxide. Only broad spectrum sunscreen products with an SPF of 15 or higher can state that they help protect against skin cancer and early skin aging if used as directed with other sun protection measures.

Water resistant sunscreen: Sunscreens are no longer allowed to be labelled as “waterproof” or “sweatproof” because these terms can be misleading. Sunscreens can claim to be “water resistant,” but they have to state whether they protect the skin for 40 or 80 minutes of swimming or sweating, based on testing.

Expiration dates: Check the expiration date on the sunscreen to be sure it’s still effective. Most sunscreen products are good for at least two to three years, but you may need to shake the bottle to remix the sunscreen ingredients. Sunscreens that have been exposed to heat for long periods, such as if they were kept in a glove box or car trunk through the summer, may be less effective.

Wear sunglasses that block UV rays: UV-blocking sunglasses are important for protecting the delicate skin around the eyes, as well as the eyes themselves. Research has shown that long hours in the sun without protecting your eyes increase your chances of developing certain eye diseases.

The ideal sunglasses should block 99% to 100% of UVA and UVB rays. Before you buy, check the label to make sure they do. Labels that say “UV absorption up to 400 nm” or “Meets ANSI UV Requirements” mean the glasses block at least 99% of UV rays. Those labelled “cosmetic” block about 70% of UV rays. If there is no label, don’t assume the sunglasses provide any UV protection.

Source: American Cancer Society, www.cancer.org

photo © Joao Virissimo

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