Sun protection is one of the key strategies to help prevent premature aging and skin cancer. A sunburn is your body’s reaction to the damage produced by ultraviolet exposure. Prevention of a burn when your skin is exposed to the sun indicates that the level of harmful UV rays necessary to produce damage was minimized or avoided. Here are a few tips to assist you in making the right choice of a broad spectrum and photostable sunscreen for your skin.
Chemical vs. Physical Sunscreens
Chemical sunscreens use chemical UV filters, such as Avobenzone, to absorb or scatter the harmful UV rays of the sun. Many of the chemical filters can absorb into the skin increasing the chance of skin irritation or an allergic reaction. They also can be unstable and start to breakdown after exposure to the sun. This reduces their efficacy and requires frequent reapplication to maintain an adequate level of protection.
In contrast, physical sunscreens, such as zinc oxide, remain on the surface of the skin and deflect or block the sun’s rays by forming a natural protective layer. They are very photostable meaning that they don’t breakdown when exposed to light and can remain effective for an extended period of time if properly applied. The chances of an allergic reaction are reduced since the physical filters are not absorbed into your skin.
Broad Spectrum and SPF: What Do They Mean?
According to Philadelphia dermatologist, Dr Franziska Ringpfeil, broad spectrum means blocking the widest range of UVB and UVA rays. “An easy way to remember the risks of ultraviolet exposure is to think of UVB as the burning rays and UVA as the aging rays because of deeper penetration without burning. Both can cause skin cancers,” says Dr. Ringpfeil. This is an important factor to consider in selecting your sunscreen because inadequate coverage leads to accumulated damage over time. New rules, recently announced by the FDA for 2012, specify that designating a sunscreen product as broad spectrum must signify that equal UVA and UVB protection is provided.
SPF or Sun Protection Factor measures how long a sunscreen will protect you from burning and is not an indicator of the strength of the protection. For example, if it takes you 20 minutes to get a sunburn, an SPF 15 will allow you to stay out in the sun 15 times longer, or 5 hours, without burning. The higher the SPF number, the longer the time period of protection against the sun’s harmful burning rays and the less frequently you will need to reapply. Products with an SPF15 block 93% of UVB rays and products with SPF30 block 97%.
Unfortunately, there is no standardized UVA sunscreen protection rating system as yet. Both short and long UVA rays are most reliably blocked by a physical sunscreen such as zinc oxide or titanium dioxide. Chemical sunscreens such as oxybenzone don’t protect against long wave UVA rays.
Dr. Forley recommends the non-comedogenic, fragrance-free, and paraben-free EltaMD® physical sunscreen product line. Each sunscreen incorporates microfine, transparent zinc oxide that leaves no white residue on the skin’s surface while providing broad-spectrum protection.
Proper Application Techniques
Once you have chosen a sunscreen it is important to apply it correctly and regularly. It is recommended to use one ounce of sunscreen for the entire body 15-30 minutes prior to sun exposure making sure to reapply after swimming or heavy perspiration. It should go on after using moisturizer but prior to makeup. Even water resistant sunscreen products should be reapplied as skin oils can negatively affect the adequacy of coverage. The new FDA rules will require the amount of time a sunscreen product remains water resistant to be specified on the label.
Combining a daily sunscreen regimen with sun protective hats and clothing offers another way to protect skin from the harmful effects of the sun. Sun-protective fabrics differ from typical summer fabrics in several ways: they have a tighter weave or knit and are usually darker in color. Ultraviolet Protection Factor (UPF) measures the level of protection the garment provides from UV rays. For example, if clothing has a value of UPF 20 the fabric will reduce your skin’s UV radiation exposure by 20 times.
- UV rays penetrate clouds and glass so apply sunscreen daily and not just when the sun is shining
- If you are using any type of exfoliating skin care products, such as Retin-A or glycolic acid, you may be more sun sensitive and you should be certain to apply sunscreen daily
- Don’t forget sunscreen on your neck, chest, and hands as they are also subject to the damaging effects of UV exposure
- Avoiding the peak sunlight hours of 10am-4pm only reduces UVB exposure. UVA rays are present at equal intensity throughout all daylight hours.
Written by Dr. Forley on June 23, 2011