Body Surface Area and Sun Protective Clothing
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Why did I get a sunburn when I wore sunscreen and had a shirt on?!?
"I always wear a shirt outside so I just put sunscreen on my face."
I understand that this statement feels like it should make sense. After all, all clothing can offer some sun protection by acting as a simple barrier to the skin. The question really becomes, how much UV protection does my clothing really offer?
The other part of this question is about sunscreen. It is true that sometimes in spite of wearing sunscreen we find our skin sunburnt leaving us scratching our heads wondering why. The answer to this question lies in how sunscreens work, when they stop working, and what steps we need to take to ensure they work their best.
How much sun protection does clothing offer?
The amount of sun protection offered by clothing really depends on the type of material and the fit of the clothing. Sound familiar? Now that everyone has heard about face masks and how they work, this should offer a model on how clothing works as well. With face masks for reducing the spread of COVID, there is a similar concept of making sure the fit and material are ideal.
What aspects of clothing make a difference for UV safety?
There are 3 aspects of clothing that we need to consider when it comes to finding the sun protection offered:
- Style / Fit
The bigger challenge with clothing compared to face masks is that we focus on the entire body surface area- not just the nose and mouth!
So, break this down for me, what are my options to protect my skin from excess UV from head to toe?
First of all, remember that this is only something that needs to be considered during midday when the sun and the UV your skin could be exposed to may be in excess. The UV index before 9am in many parts of the country, even if it is sunny, is often just a 1. This means the risk of your skin being exposed to UV radiation that can potentially burn it is extremely low. Why does this matter? It matters because we do not have to think in terms of mummifying our skin in products and/or clothing all the time. We just need to take practical measures to avoid excesses in UV while still recognizing the benefits of a little healthy sun exposure.
Your options include:
- Physical protection through a combination of hats, sunglasses, sun-protective clothing, and umbrellas or other forms of shade.
- Skincare products with sunscreen additives that offer sun protection.
- A hybrid of physical protection and sunscreen products.
The first option is reasonable however difficult to plan for every single day in every circumstance. Inevitably there are often times when we may think it will just be a short time outside and realize we get a little more UV than we thought we would. That being said, this is the safest option in ideal circumstances as it is a bit more predictable in terms of knowing that the areas covered are protected.
Relying on skincare products alone such as sunscreen lotions, creams, and sticks, is actually the riskiest option for sun protection. Why? In order for skincare products to work they must:
- Be applied correctly and uniformly. This can be difficult to achieve, especially in hair-bearing areas.
- Be reapplied at least every two hours, more frequently if sweating or swimming
- Consider that depending on your distance from the equator, may not be fully effective if they are chemical sunscreens
A hybrid approach, using hats and sun-protective clothing for most of our skin and relying on sunscreen products for limited areas, is the most practical and effective approach to reliable sun protection.
What is another drawback to sunscreen products?
If you are relying on chemical sunscreen products, the risk of sunscreen absorption into our bloodstream must also be taken into consideration.
What is sunscreen absorption? Is chemical sunscreen safe?
Several studies have looked at sunscreen safety and absorption of chemical sunscreen products into our bloodstream. These studies point to 4x the safe amount of chemical sunscreen products found in our bloodstream after just one day of use in recommended amounts. We do not have enough information or research to indicate what this means to our overall health. We can only say that the safe limits of absorption were exceeded.
What difference can clothing make?
Consider this. What if you took the time to consider your clothing choices. Choose clothing that not only is made of the right textiles but also considers the fit and body surface area covered by the designs.
The result: Based on one of our parametric body surface area modeling studies, this could mean the potential for a close to 7x reduction in the need for sunscreen products. If you are using almost 7x less sunscreen, it stands to reason that you will absorb substantially less as well. There could be the potential to find that further studies show that applying sunscreen only on the exposed areas not covered by sun protective clothing could lead to the safer use of sunscreen products.
Take a look at some of our BSA studies to see how every little inch of sun protective style matters to your health!
We continue to research and study the benefits of UPF clothing. For now, we still recommend the use of physical sunscreen products containing zinc and/or titanium to minimize the risks of sunscreen use. And, of course, continue to build an understanding of the role sun-protective clothing plays in sun safety.