In 1992, scientists at Environment Canada developed a method of predicting the strength of the sun's UV rays, based on day-today changes in the ozone layer. That same year, the UV Index was developed and Canada became the first country in the world to issue nation-wide daily forecasts of the next day’s UV levels for locations across Canada, as well as holiday destinations.
The UV Index provides a daily forecast of the expected risk of overexposure to the sun. The index predicts UV intensity levels on a scale of 0 to 10+, where 0 indicates a minimal risk of overexposure and 10+ means a very high risk (see chart on the next page). You can find out the UV Index from your local weather forecast - in the newspaper, or on the radio or TV.
How Wrinkles Form
UV radiation causes the skin's supportive structures to break down at a faster rate than that attributable to the march of time. Sunlight (including “everyday” sunlight) damages the collagen fibers and causes the accumulation of abnormal elastin. The accumulation of this sun-induced elastin causes the overproduction of enzymes called metalloproteinases whose job it is to repair the damaged tissue. Normally, metalloproteinases repair sun-injured skin by manufacturing and reforming collagen. However, this process does not always work effectively because the metalloproteinases actually break down collagen as part of the remodelling process. This can result in the formation of disorganized collagen fibers known as solar scars. When exposure to sunlight is ongoing, the skin repeats this imperfect rebuilding process over and over, causing the supportive structures of the skin to become uneven. These uneven areas cause the overlying skin to develop wrinkles.
UV Light. A Primer
The sun produces both visible rays (which form the colours of the rainbow) and invisible rays. Invisible rays include ultraviolet (UV) light. Two kinds of UV rays reach the surface of the earth: UVA and UVB. UVA rays, long thought to be safe, in fact penetrate the deeper dermal layers of the skin, damaging the support structures - collagen and elastin. This inner damage causes the skin to wrinkle and sag. UVA rays also suppress the immune system, impacting the general health. (We tend to develop cold sores after spending time in the sun because the suppressed immune system permits activation of the dormant herpes virus.)
UVB rays are the chief cause of sunburn. They are absorbed by the skin's outer layer (epidermis) damaging the cells and their genetic material.
Both UVA and UVB rays can cause reddening and burning. That’s why it is important to wear a sunscreen that protects against both UVA and UVB sunlight. Since the SPF # refers only to UVB protection, you should look for the words “broad spectrum” or “full spectrum” on the packaging.
Holiday Alert!
Do you know that Spring Break is one of the worst times of year for getting a sunburn? Year after year, winter-white Canadians pack their suitcases in mid-March and head off for Hawaii, the Caribbean, or Mexico. Since they have only a week or so to enjoy the sun, the first day is spent either sunbathing or otherwise having fun on the beach. While many people apply a sunscreen of SPF 15, they forget just how powerful the rays of the sub-tropical sun are, and stay out far too long. Others fail to apply sunscreen with a high enough SPF, and find themselves with a severe burn instead of the expected golden skin-tone.
If you are going to be taking a vacation at Spring Break, keep in mind that the rays of the sub-tropical sun are far stronger than those of a Canadian summer. You will likely need a sunscreen of SPF 30 or 45 to protect your skin if you intend to spend long hours in the sun. The sunscreen should be reapplied regularly, and always after swimming or a dip in the pool. If you are snorkeling, remember that, since the water magnifies the sun’s rays, this activity can result in severe burns to the back if a waterproof sunscreen with a high SPF is not worn.
Choosing a Sunscreen
When choosing a sunscreen or sunblock for winter exposure at high altitudes or springtime exposure in sub-tropical locales, be sure that the SPF is high (30 or 45) and that the product provides broad-spectrum protection against both UVA and UVB rays.
If you plan on swimming, you will need a waterproof sunscreen or sunblock. Neutrogena Healthy Defence® Oil-Free Sunblock Lotion 45 provides broad-spectrum protection and is waterproof. Neutrogena Ultra Sheer® Dry-Touch Sunblock SPF 30 provides powerful, broadspectrum protection, with a light feel that is ideal for application underneath makeup. You can find these and other sun protection products at your local London Drugs.
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