Sun Protection Factor (SPF) Sun protection factor (SPF) is a
number on sunscreen labels that shows how long skin can be in
the sun and maintain a low risk for sunburn. The higher the SPF
number, the longer it protects a person from the sun's burning
rays. It is important to read the information on the sunscreen
label about the SPF factor listed on the label and how much
protection it gives the skin. The sunscreen should be applied
according to the directions on the label so it is most effective
in protecting the skin from the sun's ultraviolet rays. No
sunscreen gives total protection, but "broad-spectrum"
sunscreens that contain ingredients such as avobenzone,
benzophenones, cinnamates, salicylates, sulisobenzone, titanium
dioxide, and zinc oxide usually protect from ultraviolet A and B
(UVA and UVB) rays. The label of the sunscreen product will say
what types of UV rays it protects the skin from. Sweating
heavily, swimming, or doing other water activities reduces the
SPF because sweat or water on the skin w