The bottom line is that a sunscreen with a higher SPF does offer higher protection against UVB rays, but once you get past SPF 30, protection doesn't increase dramatically, and the higher number may give you a false sense of protection. Instead of letting SPF be your only guide to sun protection, avoid a burn by following a few simple sunscreen rules.
If you don't reapply, you could end up with a sunburn like this. Ouch.
1. Know thyself: If you are whiter than a sheet of paper, if your Aunt Linda has skin cancer, or if you are sensitive to the sun because of a medication or a medical condition, take extra measures. Stay out of the sun as much as possible, wear a hat when you are out, use a broad-spectrum sunscreen with a high SPF and reapply that sunscreen often.
2. Broaden your spectrum: The SPF number indicates protection only against UVB rays -- many sunscreens, even those with a high SPF, allow UVA rays to be absorbed by the skin. UVA protection is usually indicated by a "broad-spectrum" label. Look for this to ensure the most well-rounded sun coverage.
3. Here comes the sun: To be effective, sunscreen needs to be fully absorbed into the skin, so apply it 15 to 30 minutes before you even step into the sun.
New Protection against UVA Rays
The high SPF numbers on some new sunscreens might not be that useful, but their protection against UVA rays will be. The skin absorbs UVA rays from the sun, tanning beds and sunlamps. These rays won't give you a sunburn, but they can cause long-term skin damage. You should always use a broad-spectrum sunscreen to ensure protection from both UVA and UVB rays. The latest sunscreens boast new chemicals, like Mexoryl, which has proven to be one of the most effective UVA-blockers out there.
4. Reapply yourself: Whether you're lying by the pool or mowing the lawn, you'll probably be exposed to sweat or water, the natural enemies of sunscreen. To be safe, reapply after you swim or sweat.
5. Full exposure: No matter how high the SPF, sunscreen can protect only the skin it covers. The most commonly missed spots are the temples, ears, back of the neck and top of the feet. If you are sometimes guilty of losing your focus while applying your lotion, try one of the sunscreens that contains disappearing colorants, so you can identify unlotioned areas before they burn to a crisp.
For more information on SPF numbers and sunscreen, check out the links on the next page.
Related HowStuffWorks Articles
- How Sunburns and Sun Tans Work
- Sunburn First Aid
- What is Sunburn?
- How to Treat Burns With Aromatherapy
- What is the UV Index and How is it Calculated?
- Melanoma and Other Skin Cancers In-Depth
Skin Wrinkles and Blemishes In-Depth
- Emedicine: Sunburn. http://www.emedicine.com/emerg/topic798.htm
- Mayo Clinic: Sunburn. http://www.mayoclinic.com/health/sunburn/DS00964