UV Protection - Appalachian Mountain Club

UV Protection

May 14, 2004

Save your skin: How to safely worship the sun

AMC Outdoors, June 2004

By Michael Lanza

The sun is shining, the weather is sweet, and it’s summer playtime in the great outdoors. But you’ve heard that too much sun — specifically, ultraviolet (UV) radiation — can be unhealthy and dangerous. So what can you do to protect yourself from these cosmic rays?

In case you’ve been hiding under a rock in recent years, the verdict on UV exposure is in: it’s bad for you. Too much of it and you will sunburn, increasing the likelihood of skin cancer and premature aging of your skin and eyes. Even the seemingly healthy look of a tan results from your body trying to protect itself from further UV damage.

The American Academy of Dermatology reported last year that skin cancer is the most common form of cancer in the United States, with more than a million new cases each year. According to the American Academy of Family Physicians, someone dies of melanoma every hour, making it one of the nation’s leading causes of cancer death. Furthermore, there’s evidence that the body’s immune system can be compromised by to much UV exposure.

Skin damage from UV radiation is cumulative. Fair-skinned people are at greater risk than darker-skinned people (who have more melanin pigment for protection), but damage to the eyes and immune system affects everyone. Children are considered at greatest risk, because most exposure to UV and resultant skin damage occurs before age 18.

What Is UV Anyway?

The sun emits a broad spectrum of electromagnetic radiation, from the light we see to the infrared radiation that provides the warm feeling of sunlight. The sun also beams out UV rays, which  cannot be seen or felt as they bombard your skin. There are three types: UVA, UVB, and UVC.

UVA comprises the bulk of our UV exposure. Passing easily through the atmosphere’s protective ozone layer, it’s the primary cause of tans and sunburns. The ozone layer largely absorbs UVB, but enough penetrates to remain a threat. In addition to sunburn, excessive UVB exposure can cause corneal irritation, cataracts, and immune system damage. UVC, the most dangerous variety, is completely blocked by the atmosphere. Ozone levels also fluctuate, which affects how much UV is absorbed by the atmosphere before reaching Earth.

The amount of UV radiation zapping you varies tremendously, depending on location, weather, and time of day. The higher the sun is in the sky, the higher the UV levels, which reach a maximum between 10 a.m. and 4 p.m. from May through August. UV radiation is strongest under cloudless skies, but UV can also penetrate clouds. While a thick, heavy cloud cover blocks most UV rays, puffy or thin clouds let the majority pass through.

UV levels increase with altitude, because there’s less atmosphere to filter it out — sunlight exposure increases roughly 10–12 percent for every 3,000 feet of elevation gain.Bright surfaces like snow (which reflects up to 85 percent of sunlight) and water (20 percent or more) exacerbate UV exposure.

Cover, Slather, Reapply

Here’s the good news: Skin damage from UV is mostly avoidable and experts say that four in five cases of skin cancer could have been prevented with more UV protection. People who spend all day outside under a blazing sun may seem to face a daunting task trying to minimize UV exposure, but there are simple, effective methods.

Few strategies work better than covering your skin and eyes with a protective layer of clothing. Wear a hat with a wide brim that shades your face, ears, and neck, the most vulnerable areas. Don sunglasses to protect your eyes. (Also visit related article, “Seeing the Light: Protect Your Eyes with the Right Sunglasses“.)

Dress in tightly woven, loose-fitting clothes, which will effectively block UV (some UV will penetrate loose weaves and thin fabrics). Some clothing is even labeled with an ultraviolet protection factor (UPF) rating, an indicator of how much UV is blocked. For example, wearing a garment rated UPF 20 reduces UV exposure to the skin beneath by a factor of 20.

Slather all uncovered skin with sunscreen 30 minutes before sun exposure, and reapply it every two hours. All sunscreen products sold in the U.S., whether lotions, creams, ointments, gels, or even wax sticks, are required by the Food and Drug Administration (FDA) to carry a sun protection factor (SPF) rating on a scale from 2 to 50, which indicates the degree of protection provided. For example, use of an SPF 15 sunscreen allows you to stay in the sun 15 times longer before burning than you could with no protection (though variables like skin color and UV intensity cloud the picture). Experts advise against interpreting SPF to mean you can safely stay in the sun indefinitely. Sunscreen reduces UV exposure, but doesn’t eliminate it — SPF 15 blocks about 93 percent of UV rays, SPF 30 approximately 97 percent, and SPFs above 30 add only minimal increases in protection.

But SPF ratings are not as simple as they seem — SPF refers only to the product’s defense against UVA. For increased protection against UVB, look for sunscreens labeled as “broad-spectrum.” (The FDA is working on a new rating standard to address both UVA and UVB protection.)

A waterproof sunscreen will provide about 80 minutes of protection in water, while a water-resistant product lasts for half that time. The phrase “all-day protection” is just marketing hype; you still have to reapply frequently.

Lastly, most sunscreen products carry an expiration date. Sunscreen chemicals degrade over time and become less effective — don’t use it if it’s expired. If there is no date, but the sunscreen has dried up or changed color or consistency, throw it out.

Learn, Don’t Burn

Regularly using sunscreen and clothing to protect yourself will go far in saving your skin, but the following tips can help take your efforts to the next level:

• Using titanium dioxide or zinc oxide (the white stuff on the noses of lifeguards and Himalayan climbers) provides the broadest spectrum of UVA and UVB defense. These physical UV stoppers (as opposed to the chemical blockers in sunscreens) are also less irritating for sensitive skin.

• Contrary to popular misconception, a tan on fair skin offers only minimal protection from UV, equivalent to an SPF of about 4.

• Insect repellents containing DEET can greatly diminish the effectiveness of sunscreen. If bug dope is necessary, consider wearing pants and a long-sleeve shirt or use a higher SPF.

• Don’t forget your lips! When burned, they can puff up, split, and make talking and eating most unenjoyable. Frequently reapply a lip balm with an SPF of 15 or higher to avoid a sun-slapped fat lip.

• Glass largely blocks UV, and the thicker it is (think: car windshield and windows), the more effective it is. Eyeglasses vary in how well they block UV, depending on thickness.

• Children younger than one should be kept out of direct sunlight. All children below age 15 have more sensitive skin and eyes than adults — protect them with sunblock, clothing, and sunglasses that block UV. Encourage children to use sun protection and take rests in the shade

• Avoid artificial tanning beds and discourage young people from using them. They predominantly emit UVA radiation, though some newer tanning beds produce higher levels of UVB to speed the tanning process.

• Pay attention to the daily Global Solar UV Index, or UVI, reported by the National Weather Service. On the UVI scale, 2 or under is low (unprotected skin will burn in about 60 minutes), 3–5 is moderate, 6–7 is high, 8–10 is very high, and  11 or higher is extreme (unprotected skin will burn in 10 minutes or less). Avoid or minimize sun exposure when the index is moderate or above.

Playing in the sun is fun. Wrinkles, eye damage, and skin cancer are not. Take a few simple precautions against UV exposure and your days will be brighter for years to come.

Michael Lanza is the author of The Ultimate Guide to Backcountry Travel.

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