Problem: Humans tend to swim, sweat, and change clothes while they are enjoying the sun. This behaviour will remove the quantity of sunscreen on the skin likely before the 5 hours of promised protection is up.
Conclusion: High SPF gives us a false sense of security when our summer activities likely require reapplication sooner than the promised timeline of protection. It's more important to focus on reapplication or taking shade and covering up if you choose to do reapply. (Here is another article on the same subject by the Environmental Working Group)
The term SPF is usually referring to the sun protection factor from burning (UVB radiation). You would think that from an SPF 15 to and SPF 30 the protection would double but unfortunately this is not the case...
This image from our Safe Summer Skin Guidebook show the level of SPF and the portion of UVB that they block:
Sunscreen only works if you apply it properly. An aerosol sunscreen does not apply the same way a cream or lotion does. When it is sprayed, only some of the product covers the skin, and the rest is dispersed into the air. Although the label says SPF 45 it might only be providing coverage like an SPF 8. (Read more here)
Using a cream or lotion ensure you're aware of how much you're applying and allows you to properly apply and work the product into your skin. Ask for help if you can't reach your back :)Your best bet? Choose a mineral sunblock with either titanium dioxide or zinc oxide so you are protected against both UVA and UVB radiation. We recommend our Safe Summer Skin Cream 20%!