Health: "UV" and You

August-September 1998

This is an article from WaveLength Magazine, available in print in North America and globally on the web.

by Kathryn Gardner

One in seven Canadians will develop skin cancer during their lifetime" states the Canadian Dermatology Association (CDA). The CDA, representing 500 dermatologists across Canada, have teamed up with the Canadian Cancer Society in a nation-wide campaign to educate the public about the dangers of sunshine. The reported number of cases of skin cancer in Canada is not only rising but is in fact higher than the total of lung, breast and prostate cancers combined. "Repeated exposure to the sun's ultraviolet (UV) rays over many years is the principal known cause of skin cancer," says the CDA.

But cancer is not the only effect of the sun's UV rays. Frequent exposure to the sun also causes roughening, thinning and wrinkling of your skin, broken blood vessels, sallow or dry skin on your face and liver spots on the back of your hands. Your eyes are also in danger. Cataracts, pterygium (a fleshy growth that forms on the white of your eyes then invades the cornea) and pingueculum (a yellow patch or bump on the white of your eyes) have all been linked to UV ray exposure.

Did You Know? Skin cancer is the most common of all cancers

The common umbrella makes a great sunshade......and it's not bad as a sail

Ultraviolet light is a part of the electromagnetic spectrum that also includes x-rays, rainbows and "am" radio airwaves. Think of the spectrum as waves on the ocean. The distance between the crest of one wave and the crest of the next is called one wavelength. The number of wavelengths that crash on the beach per second would be called the frequency. The frequency of X-ray waves would be comparable to the relentless chop created by a southwesterly winter storm whereas radio waves would be similar to long lazy ocean swells on a calm day. The frequencies of the visible spectrum, detected by the human eye as colours, and invisible UV wavelengths all fall somewhere in between the high and low of the electromagnetic spectrum.

UV rays are further divided into three categories according to the frequency of their wavelength. UVA have the slowest frequency and penetrate to the deepest layers of the skin. They cause tanning and burning, wrinkling, premature aging of the skin and are potentially carcinogenic. UVB rays have a higher frequency and are stopped short at the skin's surface where they are believed to damage the skin's immune system - which can ultimately result in cancer. UVB rays also cause sunburn and skin aging. The highest frequency UVC rays are absorbed by the ozone layer in the upper atmosphere - for now anyway.

Happily, protecting yourself from the disastrous affects of UV rays is relatively easy. Simply avoid the sun between 11:OOam and 4:OOpm when the UVrays are strongest, and seek shade whenever possible.

Yeah right! This solution is impractical, if not impossible, while sea-kayaking, especially during a multi-day tour. However, once again, there is a simple answer. Create your own shade by wearing a wide brimmed hat and sunglasses that provide 100% protection from both UVA and UVB rays. Use sunscreen with a minimum SPF (Sun Protection Factor) of 15, wear protective clothing and heed warnings of the UV Index forecasts whenever possible.

Victoria resident, Heather Robertson, has been following the research into sunprotective clothing conducted in Australia since her four-year-old daughter was born. Impressed by what she learned, Heather decided to raise funds to educate the public about the hazards of, and protection from the sun's ultraviolet light. Much of her funding comes from Suit Yourself Sunwear, a shop that Heather opened in Victoria where she sells only active wear and casual clothes that have a proven SPF rating.

.But fear not, you need not go out and spend a fortune on a new wardrobe. You may already have suitable garments in your closet. "The higher the composition of synthetic fibres, the tighter the weave of the fabric and darker colours will provide better protection," explains Heather. A new white cotton T-shirt, for example, can provide a SPF of 7 but a dark blue, polypropylene, long sleeved shirt may provide an SPF many times that. For a simple test at home, hold up your clothes in front of a light. The more light you can see through the fabric, the more ultraviolet light will also get through.

As for sunglasses, Ophthalmologist Dr. Alex Porzecanski explains that the chemical added to the lenses of sunglasses to block out UV light is inexpensive. Therefore, a good pair of sunglasses do not have to break the bank. As long as they have an even shading of grey, brown or green; quality ground lenses to prevent eyestrain and a rating for UVA and UVB protection the sunglasses will protect your eyes.

Lips are particularly vulnerable to the harmful effects of the sun because lips lack melatonin, the skin's natural shield against the sun.

Sunscreens work by filtering out harmful UV rays. The higher the SPF the greater the protection, depending on many factors including individual skin type, how the lotion is applied, sweating and swimming. When the sunscreen is applied is also important. Warm skin absorbs .the lotion differently and heat causes a chemical change in the sunscreen itself. If sunscreen is applied just before you jump into your kayak instead of on your cool, dry skin first thing in the morning you can effectively reduce the protection factor by half. Sunscreen also tends to roll right off of wet skin instead of being absorbed so make sure that your skin is dry when re-applying throughout the day.

Sunblock provides a thin layer of opaque grease such as zinc oxide, talc or titanium dioxide that literally blocks out the sun's rays. These products are especially good for nose, lips and people with fair skin. Both sunscreens and sunblocks should be used in conjunction with hats, sunglasses and protective clothing. They 'provide additional protection, not a ticket to bask in the sun for hours on end.

The UV index, reported during weather forecasts and in newspapers, provides a scale ranging from 0-12 that predicts the potential danger of UV radiation. When the scale is between 0 and 3 the danger is low; from 4-6 caution is advised as some people will burn within 30 minutes; there is extreme danger with UV ratings of 7 and above. Some people can burn within fifteen minutes and everyone should re-apply sunscreen every two hours as well as after swimming or profuse sweating.

Remember that up to 80% of the sun's rays can penetrate through cloud cover and are reflected off of water, sand, snow and concrete. Paddlers should therefore take the same precautions on a cloudy day that they do on a sunny day.

Protect yourself using appropriate clothing, hats, sunglasses and sunscreen. Seek shade whenever you land and paddle before 11:OOam or after 4:00pm whenever possible: Finally, check your skin regularly fir changes in moles, sores: that don't heal, and the development of irregularly shaped or oddly coloured spots (especially those larger that the top of-a pencil eraser). If any of these problems .develop, seek advice from your doctor.

Kathryn Gardner lives in Victoria and is a frequent contributor to Wave-Length