Natural sunlight is important to maintain good health, but too much sun can be harmful. Ultraviolet (UV) rays from the sun can cause skin cancer and eye cataracts. UV rays can get through clouds, fog, and haze. Water, sand, concrete, and especially snow, can reflect, and even increase, the sun's burning rays.
The risks are much greater on a mountain than at sea level because the thinner atmosphere at high altitude filters out much less UV radiation. At an altitude of 2,000 metres, the amount of UV radiation can be as much as 25% higher than at sea level.
The risk of skin cancer is higher for people who:
Most skin cancers start in areas that are exposed most often to the sun - the head, face, neck, hands, and arms.
Reduce your exposure to the sun
Protect yourself and your family, particularly between 11 a.m. and 4 p.m., when the sun's rays are at their strongest, or any time of the day when the UV Index is 3 or more.
Try to plan outdoor activities before 11 a.m. or after 4 p.m.
Stay in the shade
When you are outside, especially between 11 a.m. and 4 p.m., try to stay in the shade. Be prepared for places without any shade by taking along an umbrella.
Consider the need for shade around your home where you and your family spend time outdoors, such as backyards, children's play areas, and patios. This may include planting trees, putting up garden tents, adding an awning to your home or building a patio roof. Remember to review the sun's path around your home before building or planting to make sure the structure or trees will provide effective shade.
Wear a hat, sunglasses, and protective clothing
Wear a hat with a wide brim that covers your head, face, ears, and neck. Hats like baseball caps won't give you enough protection.
Sunglasses can help prevent damage to your eyes by blocking a large amount of UV rays. Pick sunglasses with:
Cover your skin to protect it from the sun. Choose clothing that is:
Wear sunscreen
Use a sunscreen with a sun protection factor (SPF) of 15 or higher. You need SPF 30 if you work outdoors or if you will be outside for most of the day.
Look for "broad spectrum" on the label. This means that the sunscreen offers protection against both UVA and UVB rays.
Apply sunscreen generously, at least 20 minutes before going outdoors.
Reapply sunscreen every 2 hours, or more often if you have been swimming or perspiring or if it's rubbed off.
Sunscreens cannot absorb all of the sun's rays. Use sunscreen along with shade, clothing, and a hat - not instead of them.
Remember you may also need sun protection in the winter, when you are in water, and even on cloudy days.
Protect children
All children should be protected from the sun. Children generally spend much more time outside than adults. By teaching your child sun safety while they're young, you are protecting them now, and reducing their risk of developing skin cancer in the future.
Additional resources
Prepared by the Canadian Cancer Society. This information appeared originally on the Canadian Health Network Web site.