The Greatest Health Risk in the Outdoors

2001, May/June Adirondac Adirondoc

I always have an exciting time at meetings of the Wilderness Medical Society. Discussions of helicopter evacuations, technical extractions from canyons, new approaches to immersion hypothermia and the like can really get the adrenaline flowing.

Listening to such presentations, however, it would be hard to keep in mind what the Society has recently classified as the most serious health risk facing outdoor recreationists. This risk is present in almost all outdoor sports, and may be responsible for as may as 7,000 to 8,000 deaths annually. It is hardly as dramatic as becoming trapped in a slot canyon, yet it takes more lives in a year than mountaineering does in a couple of decades.

The danger? Sun exposure.

Sure, most of us have experienced a sunburn at some point in our lives. While a nuisance at the time, we probably did not regard it as life threatening. We now know, however, that sunburn is one of the major contributors to a particularly nasty form of skin cancer, melanoma. The most common form of cancer in Caucasians between the ages of 25 and 29, melanoma has nearly doubled in incidence during the last two decades. ยท .

Much has been learned about this cancer recently. In particular, it is known that simply having a history of three or more severe (blistering) sunburns before age 20 is a major predisposing factor. Although genetic factors apparently play a role in the disease as, well, many of these cancers must be considered completely preventable.

Prevention of damaging sun exposure begins with accepting the fact that ‘ the concept of a “healthy tan” is an oxymoron. Sun-induced skin injury is cumulative, so prevention needs to be a continuing process. Many forms of outdoor recreation popular with readers of this magazine are particular risks ‘ for sun exposure. Canoeing on an open lake, for example, provides exposure both to direct sun and to radiation ref1ected from the water and (for the aluminum fan) the canoe bottom. Hitting an open summit on a warm day can be particularly problematic. In addition to the obvious lack of shade, the hiker may be overheated from a long climb and anxious to shed clothing to expose as much skin as possible. The presence of a cool summer’s breeze may be just enough to take one’s mind off of the ongoing sun exposure. Clouds are not always protective: ultraviolet exposure can actually be increased on an overcast day.

The first step in sunburn protection is proper clothing. A wide-brimmed hat, for example, really helps protect two particularly problematic areas: the nose and ears. The real key to sun protection, however, is the use of a sunscreen. There are a variety of these on the market, virtually all of which are based on para-aminobenzoic acid (PABA). Sunscreens are identified by their “sun protection factor” (SPF). An SPF of 10, for example, means that an individual protected by the product could spend ten times as long in the sun as an unprotected person while receiving the same amount of solar radiation. The cost of sunscreens varies widely: from a practical standpoint, however, there is no appreciable difference between sunscreens with the same SPF.

An SPF of 15 is probably the best for most outdoor activities. Higher SPF products tend to be more expensive. Reapplying the 15 SPF product after a few hours may be just as effective as using a higher SPF preparation. Even “waterproof’ sunscreens are lost with heavy sweating and wiping; frequent reapplication during the high radiation times of the day (10 AM to 2 PM) is prudent.

There are also a variety of specialty sunscreens to consider. Lips may be particularly sensitive to sun exposure, and combination lip balm/sunscreen products are available. For particularly severe exposures (e.g. . very high altitudes, snow and glacier travel, lengthy open water exposure) there are products which completely block the sun’s rays. These contain pigments such as titanium dioxide or zinc oxide, and are useful on the nose, ears, and similar areas. They are colorful, and also make a fashion statement!

Do not neglect your eyes while protecting your skin. Ultraviolet exposure can cause both acute (e.g., snow blindness, a temporary but disabling affliction) and long term injury (e.g., cataracts) to the eyes. Sunglasses with adequate ultraviolet protection are critical items of equipment. As with sunscreens, there is little relationship between the cost of sunglasses and their function in filtering ultraviolet light.

Finally, there is some new information about other risk factors for melanoma. These risks (in addition to having a history of three sunburns, discussed above) include: blond or red hair; a family history of melanoma; a “premalignant” skin lesion called solar keratosis; atypical moles; extensive freckling of the back; working three or more summers at an outdoor job as a teenager. An individual with one or two of these risk factors has a threefold increase in lifetime melanoma risk. Having three or four of these risk factors increases this risk by a factor of 20 to 25. At risk individuals should probably have a regular complete skin examination by a dermatologist.

~More information on melanoma prevention and screening is available from the Skin Cancer Foundation, 245 Fifth Avenue, Suite 1403, New York, NY 10016 (212-725-5176).

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Topics: Environment