After our fair province's particularly harsh winter, who wouldn't get excited about going outdoors and enjoying a Manitoba summer?
Before you bolt into our prairie sunshine, consider this: Rates for melanoma, the most serious and deadly form of skin cancer, have risen 15-fold over the last five decades in our province.
Much of this damage is caused by the sun's ultraviolet (UV) rays -- UVA, which is more closely associated with aging, and UVB, which is linked to sunburns. Both UVA and UVB cause skin damage and skin cancer.
Some factors contributing to the rise in skin-cancer rates, such as our aging population and ozone depletion, cannot be changed. We can exercise some control over how much sun we are exposed to. Exposure to UV rays from the sun and tanning equipment causes 50 per cent to 90 per cent of skin cancers. That means as many as nine out of 10 skin cancers could be prevented by using sun/UV protection.
There are many ways to protect your skin, but most people associate sun/UV protection with sunscreen or sunblock. In the past, the terms sunblock and sunscreen referred to two different types of UV barriers. However, these terms are now used interchangeably by users and industry alike.
Sunscreens use two different UV barriers -- physical and chemical. Physical barriers (ingredients such as titanium dioxide and zinc oxide) are designed to scatter and reflect UV. Most products on the market now contain chemical barriers that absorb UV to stop it from absorbing into your skin.
Sunscreens have a sun-protection factor (SPF) that indicates how long sunscreen-protected skin can be exposed to UVB before you start to get a sunburn, compared to unprotected skin. An SPF of 30 or higher is a good choice. If your unprotected skin burns after 20 minutes in the sun, applying SPF 30 sunscreen can extend protection to 10 hours before burning (20 minutes multiplied by 30 equals 600 minutes).
However, most people don't apply enough sunscreen to achieve optimal protection. Use a teaspoon for the face and a palmful for each arm or leg. To maintain effectiveness, sunscreen needs to be reapplied every two hours and after swimming or sweating.
A little-known, but important, fact is SPF refers only to protection against UVB, so it is important to choose a broad-spectrum sunscreen that offers UVA protection, too. Looking for the Canadian Dermatology Association logo as you comb through the sunscreen aisle can help with your selection. The CDA logo on the bottle means it has been tested for safety and effectiveness.
A common myth is the chemicals contained in sunscreen are more harmful to your skin than the damage caused by sun and UV rays. Research shows even if a sunscreen's ingredients could sink deep into skin, the chemical levels are too low to be toxic to the underlying cells.
However, do not use sunscreen on babies younger than six months old as their skin is much thinner, and they are at greater risk of toxicity due to their weight. Keep babies in the shade and cover their skin as much as possible. Also, check expiry dates and don't use sunscreens that have been exposed to extreme heat or cold. While it is not dangerous to use expired sunscreen, you are likely not getting the protection you need.
In addition to these recommendations, don't overlook other methods of sun/UV protection. Pairing sunscreen with long sleeves and pants, using wide- brimmed hats and sunglasses with UVA and UVB blocking lenses can make the day more enjoyable. Be mindful of the time of day (peak times are between 11 a.m. to 4 p.m.) and seek shade.
Dr. Donna Turner is an epidemiologist and provincial director, population oncology, at CancerCare Manitoba.