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Sun Smarts

Il processo di abbronzatura è la prima linea di protezione messa in atto dal tuo corpo prima dell'espozizione eccessiva. Quando il tuo corpo è esposto ad un livello di radiazione UVA troppo elevato, speciali celle pigmentate chiamate melanociti si scuriscono nel tentativo di creare uno schermo protettivo per difendere la tua pelle da danni causati in seguito ad una eccessiva esposizione. Più scura diventa la cella, più grande è il livello di danno per la tua pelle. Scottature si evidenziano quando un'eccessiva radiazione UVA oltreppassa queste protezioni.

Oltre a praticare solamente immersioni notturne, ci sono poche cose che i subacquei possono fare per limitare l'esposizione ai raggi UVA:

• Avitare le ore più pericolose di esposizione: L'orario compreso tra le 10 a.m. e le 3 p.m., quando il sole è più alto nel cielo, sono presenti i più forti raggi UVA i quali causano i maggiori danni. Limita la tua espo during these hours as much as possible. Keep in mind that sand, water and pavement are excellent reflectors of UV rays, and can burn you where you least expect it (like the bottom of your chin) and even cause damage while you're under a beach umbrella or boat cover.
• Cover up: Light-colored clothing with a tight weave provides the best protection from the sun. Hats help shield the face; for maximum protection they should also cover the back of the neck.
• Use sunscreen: OK, this one seems obvious, but many divers don't use the right sunscreen, enough of it, or apply it properly.

In order to be truly effective, sunscreens need to be applied before you go out into the sun, and reapplied at least every two hours. Use lotion more frequently if you are sweating or have been in the water, and make sure that all exposed skin is protected, including the nose, back of the neck, and tips of the ears. The lips have no natural protection against sun damage, so use lip balm with SPF protection.

The American Academy of Dermatologists recommends that everyone use a broad-spectrum sunscreen with an SPF of at least 15. For help choosing the right sunscreen, see Sun Screening.

• Protect your eyes: UV rays can also burn the retinas and lead to cataracts. Make sure that your sunglasses screen out at least 98 percent of UVA and UVB rays. Some cheap sunglasses don't and they make matters worse by dilating the pupil and letting more radiation in. Get a pair of stylish wraparound sunglasses or a pair with side shades to maximize protection of the eye and lid.

Risky Business

Overexposure to sunlight is the single greatest risk factor for skin cancers. Fortunately, it's also the easiest to control. There are many risk factors for skin cancer over which we have little or no control. They include:

• Skin color: Pale-skinned Caucasians, particularly those with red or blond hair, are as much as 20 times more likely to get skin cancer than dark-skinned African-Americans.
• Hereditary factors: People with a family history of skin cancer are at greater risk, as are those of Northern European descent.
• Gender: Men are two to three times more likely than women to have certain types of skin cancers.
• Environmental factors: People with a history of radiation exposure, such as from cancer radiotherapy or UV treatments for psoriasis, have an increased risk of developing skin cancers. So do workers with industrial exposure to arsenic, coal, tar, paraffin and certain oils.
• Previous skin injuries: People who have suffered severe burns or have had chronic inflammation of the skin due to infection are also at a higher risk of developing skin cancers on or near the affected area.
• Reduced immunity: People whose immune systems are compromised, either through genetics, chemotherapies or HIV, are at increased risk of skin cancers.
• Medications: Medications, including many common antibiotics, increase skin sensitivity to sunlight.

People in high-risk categories should be especially careful about managing sun exposure and should never try to tan. Not only are they more likely to get burned, they are far more likely to suffer long-term effects from sun damage.

Sun Screening: Choosing and Using the Right SPF

Determined not to burn on your next tropical dive vacation? Good. A bottle of sunscreen, applied often, will go a long way toward avoiding painful sunburns and long-term skin damage. Here's what to look for:

• A high SPF: The most important factor in choosing sunscreen is the SPF, or sun protection factor number. SPF is a measurement that helps you figure out how long you can stay in the sun without getting burned. Take the amount of time you could stay in the sun without protection, then multiply it by the SPF number. In other words, if you would normally burn in 10 minutes of direct sun, using an SPF 4 sunscreen would extend that time to 40 minutes. An SPF 15 sunscreen would give you 150 minutes.
• But not too high. The American Academy of Dermatologists recommends that everyone use sunscreen with an SPF of at least 15. While manufacturers market sunscreens with SPFs of 30, 45 and higher, the general consensus is that these preparations probably don't provide significantly greater short-term protection than properly used SPF 15 lotions.
• Never mix. Remember that you can't mix sunscreens to get more protection (SPF 4 and SPF 2 do not make SPF 6) and, if you have already spent your 40 minutes in the sun with SPF 4 lotion, applying another layer doesn't get you more time. Nor does applying a higher SPF lotion - you're done for the day.
• Broad spectrum protection: Sunlight contains two types of UV rays: UVA and UVB. Most sunburn is caused by UVB rays, and SPF measures protection only against UVB.

UVA rays, which also damage the skin and can lead to cancer, are blocked to varying degrees by ingredients such as benzophenone, oxybenzone, sulisobenzone, titanium dioxide, zinc oxide and avobenzone. Only when a sunscreen includes one or more of these ingredients can it be labeled "broad spectrum" under FDA rules.