The Definitive Guide To Choosing A Good Sunblock

My recent sunburn has prompted me to review the subject of protecting myself from the harmful effects of UV radiation.  This is a subject I don’t want to take overboard, because I enjoy being outside in the sun as much as the next guy, and I don’t expect that to change anytime soon.  But I also acknowledge that facts are facts.  Most experts agree that repeated overexposure to sun is the leading cause of skin cancer.

Why Worry About Sunblock?

Energy is transmitted to the earth in the form of solar radiation.  This includes ultraviolet (UV) radiation, which is not visible to the human eye.  UV radiation is divided into two categories, being UV-B and UV-A.  UV-B includes the wavelengths between 320-290 nm, while UV-A is the ranges from 400-320 nm.

UV-B radiation the more energetic of the two categories, and is generally thought to be responsible for sunburns and skin damage.  UV-A, being longer wavelength, is less energetic.  However, this allows a greater depth of penetration into the skin, and is therefore thought to be more responsible for skin cancers and skin aging.

Choosing A Good Sunblock

Sunblock, (or sunscreen), is widely used as a barrier to provide protection against UV exposure, so its important to gain an understanding of how sunblock is rated for effectiveness.  The vast majority of products are gels or lotions, that are spray applied or rubbed in place by hand.  These products function by absorbing and/or scattering ultraviolet radiation, thereby preventing UV rays from causing damage to the skin.

Most countries use the Sun Protection Factor (SPF) rating system to describe the effectiveness of sunblocks at providing protection against UV-B radiation.  Working from the assumption that it would take longer for someone wearing sunblock to get a sunburn, the SPF number describes how much longer that person could be exposed and not suffer the same burn.  For instance, someone that would normally sunburn after 20 minutes in the sun could expect to tolerate 400 minutes of exposure if they were wearing a SPF 20 sunblock.  This assumes about 1 ounce of sunblock is used to cover the exposed skin of someone in a traditional bathing suit.

Unfortunately, the SPF system does not even address the issue of UV-A exposure.  The is a severe oversight, as some experts now believe that although UV-A is not responsible for sunburns, it does penetrate deeper into the skin, where it can cause DNA damage.  Some studies also tie UV-A exposure to an increased risk of malignant melanoma.  Products that contain zinc oxide, titanium dioxide, avobenzone, and ecamsule are generally effective at reducing the risk of damage from UV-A exposure.

There is some debate about the safety of sunblock products, due to the risk of chemical exposure.  In general, choosing products based on ingredients such as zinc and titanium dioxide is considered the most conservative approach.  You can see a review of many sunblock products at then environmental working group’s website.

Moving Beyond Sunblock

Australia has the highest rates of skin cancer of any country in the world.  This is probably not surprising, since the proximity to the equator leads to higher levels of UV exposure.  This has also led them to advance the science of UV protection.  Specifically, they have pioneered the advancement of UPF system of rating the effectiveness of clothing to provide UV protection.

It is generally accepted that the use of clothing, a broad brimmed hat (not a baseball cap), and sunglasses provide the best UV protection.  The UPF system (Ultraviolet Protection Factor) moves beyond the SPF system to include protection from UV-B and UV-A radiation.  You can now find a variety of clothing on the market that is rated for UPF protection.  Generally speaking, factors such as color, weave, weight and wetness greatly affect protection.  It is specifically noteworthy that wet clothing provides less UV protection than the equivalent dry clothing.  Generally speaking, if there is not a UPF rating, you can expect clothing with an open weave or light color to provide less protection than a tightly woven, dark colored garment.  That trend doesn’t exactly scream comfort on a hot day.

Fortunately, manufacturers have developed a lot of options if you’re interested in protecting yourself.  Most sporting goods stores carry UPF rated clothing these days.  This clothing is made specifically to combine UV protection and comfort.  You end up finding features like vented backs and arms, and lighter colors made of tightly woven material.  In these, the weave and fabric selection provide the majority of the protection, rather than color.

So there you have it.  Your ultimate guide for selecting protective gear for summer fun.

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