SUN PROTECTION
THE SUN AND SPFEXPLAINED
By Elizabeth Rostan, MD
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Quick Look
SUN DAMAGE
Around age 30, our skin stops producing collagen. Aging and sun damage lead to collagen loss as well as loss of elastic tissue in our skin. Collagen can be thought of as the strength of our skin and elastin the stretch or rebound of our skin. This collagen and elastin loss continues and leads to fine lines, sagging skin, wrinkles, and texture changes.
TYPES OF SUNSCREEN
Physical sunscreen WORKS LIKE A SHIELD; it sits on the surface of your skin, deflecting the sun’s rays.
Active Ingredients
- Zinc Oxide
- Titanium Dioxide
Chemical sunscreen WORKS AS A SPONGE; absorbing the sun’s rays.
Active Ingredients
- Oxybenzone
- Avobenzone
- Octisalate
- Octinoxate
WHY IT MATTERS
Exposure to UV radiation increases your risk of skin cancer, and it’s estimated that about 80% of skin’s aging comes from the sun.
Photo: Young Elizabeth Rostan
In my youth, I spent countless hours outdoors with almost no sunscreen. When I was a teen in the 80’s, getting that great tan was a primary goal – and a goal my friends and I worked hard on! In medical school, I had rotations in dermatology where I saw first hand the effects of too much sun.
As part of training, we also studied tissue under the microscope and believe me, if you see what the sun damage can do at a cellular level, it is enough to make you want to stay out of the sun! I began to learn also the cosmetic consequences of too much sun exposure – wrinkles, sagging skin and blotchy skin. Indeed, the changes of sun on our skin far outweigh the changes of aging.
So, in my early 20’s I began to change how I spent time in the sun and how I protected my skin.
Let me share what I now know and practice. In this blog series, we will review the sun and its effects on your skin, help explain SPF and how sunscreen works, and outline great sun protective behaviors for a lifetime of healthy skin.
The Sun and Your Skin
Ultraviolet Rays
The sun emits ultraviolet radiation in 3 forms:
- UVA (95% of sun’s rays that reach Earth)
- UVB (5% of sun’s rays)
- UVC
UVC is completely blocked by our atmosphere and does not reach earth. UVA is longer wavelengths and referred to as the “aging sun rays”. UVB rays are shorter wavelengths and called “sunburn rays” – but both can lead to skin cancer. Tanning beds can emit rays 10-15 times stronger than the sun.
Types of UV
UV INDEX
Low 1-2
No protection needed
Moderate 3-5
Some protection is required
High 6-7
Protection essential
Very High 8-10
Extra protection needed
Extreme 11+
Stay Inside
How The Sun Damages Skin?
DNA damage and skin cancer
UV rays from the sun damages DNA in skin cells. DNA makes up the genes that drive our cellular functions – life’s engine.
When DNA is damaged, genes in our cells are defective and some genes that cause growth can be turned on – causing cells to grow unchecked ie a tumor – while other important genes called suppressor genes that inhibit tumor growth may be turned off.
So, sun damages DNA causing some genes that drive tumor growth to be turned on indefinitely – the accelerator on life’s engine. At the same time, DNA damage leads to loss of tumor suppression genes – brakes don’t work. So accelerated, abnormal growth without any brakes – skin cancer.
