Tip Of The Season
UV Rays and SPF Protection
SPF stands for sun protection factor. It tells us how well the sunscreen protects us against UVB rays, but has nothing to do with UVA radiation. Why does this matter? Read on…
UVB rays are referred to as “ burning ” rays. They are the rays that cause us to get sunburns…their effects can be immediate and harmful.
UVA rays are thought of as “ aging ” rays. These rays are responsible for most skin cancer, as well as signs of premature aging (like wrinkles and sun spots)! The scary fact about UVA rays is that they don’t necessarily produce any visible redness on the skin, so we don’t get any sign when they are bombarding us.
So…back to SPF. This number basically represents the amount of time you can stay outside without burning. Let’s say it takes about 30 minutes in the sun before you start to get red…an SPF2 protects you from 50% of the sun’s rays, so you can stay outside 2 times longer than normal without a burn (1 hour). SPF8 blocks 87.5% of UVB rays, and allows you to stay out for 4 hours before turning red.
Taking this into consideration, we see that SPF30 should not really be exceeded. There aren’t enough hours in the day to need such a high SPF! A high SPF doesn’t mean more protection…it just contains more chemicals (an can potentially product a chemical burn).
How does sunscreen work?
There are 2 types of sunscreen: chemical and physical
Chemical sunscreens work by absorbing UV radiation . This lowers the energy level and releases that energy as heat.
Physical sunscreens scatter or reflect the rays .
Chemical sunscreens are thought to be more effective, but some skin simply cannot tolerate these chemicals. For sensitive skin, choosing a pure physical sunscreen is ideal.
Zinc Oxide and Titanium Dioxide are the most recognized physical sunscreen ingredients.
The following depicts ingredients used in Dermalogica's Solar Defense line, and the UV rays they protect against:
Safe Sun Tips
- Apply about 1 teaspoon of sunscreen on the face, and 1 ounce on the body
- The National Cancer Society recommends reapplying every 2 hours (more if you are swimming or exercising)
- Try to avoid the sun between 10 AM and 2 PM…that’s when UV radiation is strongest
- Be very liberal with sunscreen when you’re around snow or water…90% bounces back!
- Altitude also require extra protection…UV potency becomes 4% stronger with every 1,000-foot increase
- Don’t rely on SPF makeup alone…it’s great to use the extra protection, but we typically don’t apply enough to provide sufficient protection
- Wear SPF15 to SPF30 every day…UVA rays can penetrate glass, and a cloudy sky does not mean that you aren’t getting bombarded with UV rays
- A general rule of thumb is to keep small babies out of the sun until 6 months…after 6 months, sunscreen may be applied (it’s always recommended to speak with your physician first)
- If you want to wear a moisturizer along with your sunscreen, always apply sunscreen LAST
- Apply sunscreen 15 to 20 minutes before going outdoors