Many people underestimate the risks involved in prolonged and unprotected exposure to the sun. The rate of skin cancer is on the rise in Canada, as it is in most industrialized countries. New research data reminds us how important it is to regularly apply enough sunscreen when we take part in outdoor activities.
British researchers report that when we rub sunscreen in too vigorously, we can greatly decrease its protective effects. They used left-over skin from plastic surgeries and recreated intense sun exposure conditions in the lab. They then measured the skin’s levels of free radicals, which are tissue-damaging particles created by the effects of ultraviolet rays. They found that the levels rose in direct relation to exposure to the sun’s UVA rays, which are linked to cancer and premature ageing of the skin.
They found that when the sunscreen was rubbed in, it accumulated in wrinkles and sweat glands and therefore did not protect skin evenly. Protection against UVBs, the rays that cause skin to redden and burn, was not affected by rubbing. UVBs can also cause cancer.
The team sees a danger in these findings because people feel protected when they apply sunscreen and consequently tend to stay in the sun longer. The best protection against the sun is still to wear skin-covering clothing, a hat (particularly if your scalp is starting to be exposed) and sunglasses that filter UVAs and UVBs. The Canadian Dermatology Association also recommends staying in the shade between 10 a.m. and 4 p.m., the period when the rays of the sun are at their strongest. When exposure cannot be avoided, it is important to apply a sunscreen or sunblock.
Are you still using that tube of sunblock you bought for your family three years ago? Then, like many people, you are probably using it wrong. Experts recommend applying a generous layer of sunscreen (SPF 15 or higher against both UVA and UVB rays) on all exposed areas of the body at least 15 to 30 minutes before going out. The cream should be applied carefully and be reapplied every two hours (or sooner if you have sweated profusely or gone swimming). If you see a white film on your skin, then you have applied enough cream. The nose, ears and lips are particularly sensitive and are often forgotten when applying sun protection. Cloudy days offer no defense against the sun: nearly 80% of UV rays make it through the clouds. We must therefore take the same precautions no matter what the weather or the season. If you follow these recommendations, you should use at least one tube of sunscreen or sunblock per person over the summer.
The products contained in sunscreens are only stable for a short period of time. If they are exposed to heat and humidity, they will deteriorate more quickly. Likewise, an expired sunscreen doesn’t provide adequate skin protection. If you have any questions when buying a sunscreen or sunblock, don’t hesitate to consult your pharmacist!