Testing Your Skin Type/Subtype IQ
Understanding Your Tanning Potential

by Patricia Reykdal and Donald L. Smith

Constitutive Pigmentation

Our constitutive pigmentation is our natural skin color and it is based upon our genetic heritage. As a rule of thumb, the darker our natural skin color, the greater is our protection from overexposure to UVR and it provides our only permanent means of photoprotection.

Individuals who are Skin Type 0s (albinos) and Skin Type 1s (the most sensitive Caucasians) have the highest relative risk of sunburning.

Facultative Pigmentation

Our facultative pigmentation--better known as a "tan"--is our level of acquired or adaptive photoprotection to UVR. This means of protection from UVR is transitory since a tan can, and usually does, darken or fade over time and season of year.

Adaptive pigmentation provides the natural equivalent of SPF 3 to SPF 5 protection from the sun. Skin Type 0s have no photoprotective constitutive pigmentation, and Skin Type 1s, who have minimal levels of natural skin color, are genetically incapable of developing adaptive pigmentation. These individuals must wage a life-long battle against the sunburning power of UVR utilizing sun avoidance, protective clothing and sunscreens.

Sunburning

The sometimes painful process of sunburning is the third natural way we have to protect our DNA from damage. The redness and swelling associated with a sunburn serves to protect us from further acute damage to UVR and is Mother Nature's way of letting us know that we haven't been very smart.

Before discussing how to determine your Skin Type/Subtype, it is essential to know the reasons why it makes sense to know your Skin Type and your Subtype. The graph on the next page shows the time it will take to sunburn for the various Skin Types/Subtypes in the sunlight experienced by much of the country at noon on a typical summer day (6 UV Index unit reading). For this example, it is assumed that no base level (facultative pigmentation) of tan exists.

As you can see, a Skin Subtype 2A has 21 minutes until they will accumulate 1 MED (minimal erythemal dose of ultraviolet radiation) which is the level at which they will experience a sunburn. A Skin Subtype 3A, on the other hand, can tolerate double this amount--42 minutes--before suffering a sunburn. A Skin Type 5 (brown-skinned individuals) can tolerate 72 minutes of exposure to sunlight without sunburning, while a Skin Type 6 (black-skinned individuals) can tolerate 84 minutes.

The graph shows very clearly why it is necessary to know your Skin Type and your Subtype in order to accurately predict the time it will take you to sunburn. Tolerance to UVR is Skin Type/Subtype dependent--the darker your natural skin color, the greater your tolerance to UVR.

If you are familiar with Skin Typing but not Subtyping, knowing both terms is necessary in order to prevent sunburning. For instance, if you look at the mid-point of the Skin Type 2 segment of the population (Skin Subtype 2Bs), you will see that it takes 28 minutes to sunburn. If you applied that tolerance level to Skin Subtype 2A individuals who have a tolerance of 21 minutes, you can see that 2As would be exposed to seven minutes of UVR more than can be tolerated by these sun-sensitive people. This additional time is more than sufficient to cause a sunburn.

Moreover, if a Skin Subtype 2A individual would base their calculation time for sunscreen protection on the tolerance level of a Skin Subtype 2B, the seven-minute error is multiplied by the protection factor. For example, if a sunscreen with an SPF 8 is applied, a Skin Subtype 2B would have 224 minutes (8 x 28 minutes) of protection, while a Skin Subtype 2A would have only 168 minutes (8 x 21 minutes). The difference of 56 unprotected minutes is more than enough to cause a painful sunburn.

Keep in mind that you must apply the proper dose of sunscreen in order to obtain the rated protection. It takes 1.25 ounces--a full handful--of lotion for a full-body application on an adult. If you only use one half as much as you should, you will cut down the protection by 50 percent; therefore, an SPF 8 becomes an SPF 4 sunscreen. In addition, you should reapply the lotion every hour and every time you get wet in order to be fully protected.

The questionnaire on page 34 allows you to calculate your own Skin Type/Subtype. Since your natural skin color doesn't change, you can use this value for the rest of your life.

Although the rewards of sensible, moderate and responsible exposure to UVR outweigh the minimal and manageable risks involved, you should never allow yourself to sunburn. Knowing your Skin Type/Subtype is one more tool that you can use to prevent sunburning. Once you know this value, you can make an intelligent decision regarding the use of artificial means of photoprotection, i.e., the use of sunscreens containing various levels of SPF.

The first rule of sensible, moderate and responsible exposure to UVR is NEVER allow yourself to sunburn.

MOTHER NATURE, IN HER INFINITE WISDOM, HAS PROVIDED US WITH THREE SEPARATE WAYS TO AVOID OVEREXPOSURE TO ULTRAVIOLET RADIATION (UVR). OVEREXPOSURE IS DEFINED AS A DOSE OF UVR SUFFICIENT TO CAUSE A SUNBURN, WHICH CAN DAMAGE OUR DNA. ON THE OTHER HAND, EXPOSURE IS DEFINED AS A DOSE OF UVR BELOW THE LEVEL NECESSARY TO CAUSE A SUNBURN. OUR THREE NATURAL WAYS OF PREVENTING SUNBURN ARE CONSTITUTIVE PIGMENTATION, FACULTATIVE PIGMENTATION AND SUNBURNING.