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Old 07-09-10, 01:17 PM
  #22  
electrik
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Originally Posted by spooner
Or for a SPF of 70 you would burn after 700 minutes. That is over 11 hours! You are likely to sweat off the protection before it wears off.

Anything over SPF 30 is over protection.
Well, that is the thing... you will sweat if off. In general though the higher the SPF the greater your chance at protection. You don't want a sunburn, so what you're doing by using a higher spf is lessening that risk and lessening the uv a/b radiation getting into your skin. It is important to note that a sunburn doesn't happen immediately at 700minutes. It occurs gradually over the time of 700 minutes.

In the 2007 draft rule, Food and Drug Administration (FDA) proposed to institute the labelling of SPF 50+ for sunscreens offering more protection. This and other measures were proposed to limit unrealistic claims about the level of protection offered (such as "all day protection").
However, more recent research at the University of California, Riverside, indicates that sunscreen needs to be reapplied within 2 hours in order to remain effective. Not reapplying could even cause more cell damage than not using sunscreen at all, due to the release of extra free radicals from those sunscreen chemicals which were absorbed into the skin.[5] Some studies have shown that people commonly apply only 1/2 to 1/4 of the amount recommended to achieve the rated Sun Protection Factor (SPF), and in consequence the effective SPF should be downgraded to a square or 4th root of the advertised value.[6]
- wikipedia.

This means if you misapply spf30 you could only be getting spf5!

Last edited by electrik; 07-09-10 at 01:21 PM.
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