
Two types of invisible UV (ultraviolet) rays are emitted by the sun and can lead to skin damage: UVA rays and UVB rays. It’s important to protect against UVA and UVB rays year-round.
UVA rays, like an X-ray, are able to pass through clouds, clothing, windshields and even office windows. These rays also penetrate the top epidermis layers of skin and reach through to the dermis. The dermis is a thick, supportive network of collagen and connective tissue that holds moisture and acts like a scaffold to help maintain firm, flexible skin. Prolonged exposure to UVA rays damages the dermis, causing the breakdown of collagen and loss of water, which makes skin lose its elasticity and tone. The result is sagging, wrinkles and an aged appearance to the skin.
UVB rays are the main cause of sunburn and skin cancer. They are stronger in the summer months and penetrate the topmost (epidermis) skin layers. The SPF (sun protection factor) rating on sunscreen lotions and creams indicates the amount of protection against UVB rays only. When choosing a sunscreen, look for one that offers broad-spectrum protection, which screens out both UVA and UVB rays.
Too much sun has a weathering affect on skin and leads to an aged appearance. And the cumulative effects of sun exposure can increase the risk of skin cancer. Skin cancer is the most common form of cancer in the United States. It’s believed that more than 90% of skin cancer cases are caused by overexposure to the sun. The risk of skin cancer doubles if you’ve had five or more sunburns.