Dr. Kirby's Blog

SPF – What Does it Mean?

SPF (Sun Protection Factor) refers to the ability of a sunscreen to block ultraviolet B (UVB) rays, which cause sunburns, but not ultraviolet A (UVA) rays, which are more closely linked to deeper skin damage.  Both UVA and UVB contribute to the risk of skin cancer and long-term skin damage.  The Skin Cancer Foundation reports that 90% of non-melanoma skin cancers in the U.S. are linked to sun exposure, yet many of us still are not protecting ourselves.

Any sunscreen is better than no sunscreen at all – the higher the SPF, the better:

  • Suntan lotions with a low SPF offer little to no protection against long-term skin damage and exposure-related skin cancers
  • Suncreens typically contain chemicals that act as filters to reduce the ultraviolet penetration of the skin
  • Sunblocks are products containing ingredients such as a titanium dioxide and zinc oxide which physically block ultraviolet radiation.  Sunblocks provide broad protection against both UVB and UVA light
  • Sun-protective clothing is designed to block UVB and UVA radiation

Clouds do not block the UV rays that cause sunburn, so you can still get a sunburn when it is cloudy outside.  Since UV rays can be reflected off of water, sand, snow, and concrete, you can even get a sunburn in the shade.

Everybody, regardless of race or ethnicity, can suffer from overexposure of the sun!  1 in every 5 Americans will develop skin cancer at some point during their lifetime.

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