In the latest installment of our occasional conversations with Fort Worth newsmakers, Dr. Kimberly Wolfshohl, a family medicine physician with JPS Health Network  discusses the importance of sunscreen and how it protects people from the sun’s harmful ultraviolet rays.

This conversation has been edited for length and clarity. For more, please listen to the audio file attached to this article.

Keyla Holmes: So, what is sunscreen?

Wolfshohl: In simple terms, sunscreen is a cream or lotion, or even a spray these days, that is applied to the skin and it protects the skin from the sun’s harmful rays. In particular, though, if you want to break it down further, there are two types of sunscreen. So you have chemical sunscreens and mineral sunscreens. Chemical sunscreens absorb and scatter sunlight before it can penetrate the skin. Mineral sunscreens, on the other hand, sit on top of the skin, and they act as a physical barrier against certain harmful rays that are emitted by the sun.

Holmes: Thank you. I did a bit of research and I found that the FDA recommends that you use sunscreen with an SPF of 15 or higher even on cloudy days. Can you break that down?

Wolfshohl: Yeah, so SPF stands for Sun Protection Factor. That basically just refers to how much solar energy, specifically UVB rays, is required to produce sunburn on protected skin versus unprotected skin. In simple terms, as SPF increases, your sunburn protection also increases.

However, the SPF increase from 15 to 30 is only an increase of about 93% blockage (of UVB rays) to 97% blockage; so you don’t get that much more bang for your buck with a higher SPF. The biggest bang for your buck is really an SPF of 15. That’s why the FDA typically recommends an SPF 15 for most people. 

One thing that I do want to clarify is that SPF does not indicate how long you can be in the sun without burning.  This also has to do with the sun intensity, if you’re sweating, what other physical type of activities you’re doing, because that can also affect how long your sunscreen is going to last. 

What is UV?

UV stands for ultraviolet light — the region of the electromagnetic spectrum between visible light and X-rays. UV light can be broken down into UVA and UVB. Those are the most harmful portions of ultraviolet light that we experience. 

  1. UVA — light with a longer wavelength. UVA contributes to aging. It penetrates deeper into the skin. It can cause a lot of cosmetic damage, like fine lines, wrinkles and sunspots.
  2. UVB — light with a shorter wavelength. It doesn’t penetrate as deeply into the skin, but it’s what really causes our sunburn. 

– Dr. Kimberly Wolfshohl

Holmes: Thank you for that. I just wanted to ask: Why wear sunscreen even when it’s cloudy? Is the sun still harmful?

Wolfshohl: Yeah, that is a great question. And I think a lot of people, even myself, before I started medical school and just started learning more about sunscreen and skincare, I even thought, ‘Hey, if it’s shady, why do I need to wear sunscreen? I am not in direct sunlight, I’m protected from it.’ It turns out we’re not. So ultraviolet light, especially UVA rays, can penetrate through clouds. Even in shaded areas, on cloudy days, and even in the winter, you are still receiving ultraviolet light. One thing to remember is ultraviolet light can also be reflected. It can be reflected off the water, off of snow, even off of cement and sand. Even if you’re standing directly in the shade, but you might be near a body of water or near some snow, you are still able to receive ultraviolet light just from the reflection of it. It is still important during sunlit hours of the day to be wearing sunscreen if you’re going to be outside.

Holmes: Thank you for that. Let’s talk about people of color and sunscreen. According to the FDA, people of all skin colors are at risk for sun damage. Have you encountered any misconceptions with people of color and sunscreen?

Wolfshohl: Yeah, so darker-skin people often think that they don’t need sunscreen. And I have a lot of friends — Indian, African American and other East Asian friends — that it is so hard for me to convince them to wear sunscreen. But everyone can get burned from the sun, even darker-skinned individuals. It is true, though, that fair-skinned individuals tend to absorb more solar energy than dark-skinned individuals. And this is because darker-skinned individuals have more melanin, which is the pigment that goes in skin, hair and eyes. 

Melanin has the ability to absorb UV rays. The absorption causes tanning, but the absorption also prevents the UV rays from penetrating deeper into our skin to cause damage. But darker skin people do still need to wear sunscreen because they can still burn. They can still get sun-induced damage like sunspots, wrinkles, and we can still get skin cancer. Now getting skin cancer is less likely because we do have more melanin; however, it’s still possible. When people of darker skin do get skin cancers like melanoma, because they’re darker-skinned, it tends to be a little more difficult to spot. Those cancers tend to be diagnosed at later stages, which means that the outcomes tend to be far worse. So even though darker-skinned individuals are less likely to burn and are less likely to get skin cancer, it is still important to be cautious of those ultraviolet rays and to protect ourselves from it by wearing some sunscreen.

Holmes: When it comes to choosing a sunscreen, what do you recommend? Do people of color have any other considerations?

Wolfshohl: Whenever you’re choosing a sunscreen, there are just a few basic things that I would recommend for all people regardless of skin type. Regardless if you’re fair-skinned or darker-skinned, I would always recommend choosing a mineral-based sunscreen. And I’ll tell you why in a little bit. (Also) something that’s broad spectrum, because broad spectrum means that it is providing protection against UVA rays and UVB rays. 

Aside from sunscreen, I would just recommend some more conservative protective measures such as wearing clothing, trying to stay in the shade and wearing hats. And avoiding going out during the peak UV hours of the day. The peak UV hours of the day tend to be from 10 a.m. to 2 p.m.. So during that time period, the sun is at its highest point during the day, the UV rays have the most intense shine. 

But the reason why I would recommend a mineral-based sunscreen over a chemical sunscreen is because the mineral-based sunscreens are considered more safe by the FDA. They’re also more environmentally friendly. You might have seen on the news how some sunscreens can negatively affect coral reefs. Mineral-based sunscreens tend to limit those harmful effects to the environment. Also, mineral based sunscreens tend to be more effective at reducing cosmetic damage from the sun just because you do have that physical barrier protecting your skin. So you’re less likely to have sunspots, and you’re less likely to have other sun-induced skin damage like rosacea

Lastly, because it is a mineral base and not a chemical base, you’re less likely to have an allergic reaction to it. But they do have their cons. One thing just to remember if you’re going to purchase a mineral sunscreen is that they do tend to be thicker. When you’re smearing it, it does kind of look like you’re putting on warpaint. It often does leave a white streak, so you do have to rub it in more. 

Holmes: If you don’t mind, can you tell us about your own skincare journey? And what was that like?

Wolfshohl: Yeah, I guess coming from a Chinese background —in Chinese culture, we are very into skincare, and we essentially fear the sun. So I think I grew up in a household that was very much into sunscreen. Growing up, I didn’t really understand why it was so important to wear sunscreen. What’s so bad about getting a sunburn? It wasn’t until I got older and started doing my own research and then going to med school, becoming a doctor, that I really realized the importance of wearing sunscreen to help prevent things like skin cancer. I think more recently, as they’ve done more research, I’ve kind of had a renewed interest in getting outside though, because in spite of all this talk about harmful UV rays, you don’t want people to fear the sun like I used to. I actually want to advocate for the exact opposite. 

I really, really, really want people to spend more time outdoors during the sunlit hours of the day, and I want them to feel safe about being out in the sun. Most recently, where I am in my skincare journey is just trying to maximize safety in the sun, while still spending a lot of time outdoors.

Holmes: I think safety is really important. Is there anything else you’d like to add?

Wolfshohl: I think one plug that I do want to add is the reason why I’m making such a big push to get my patients outside. Scientific research is showing that exposure to infrared light, which is part of the electromagnetic spectrum that we can’t see, but can detect as heat, has profound health benefits. The easiest way we get infrared light is being outside in the sun. So some of these health benefits include reducing your risk of diabetes, improving glycemic control if you have diabetes, improving outcomes and autoimmune diseases like multiple sclerosis, reducing your risk of melanoma, improving your cardiovascular health like lowering your blood pressure, lowering your heart rate, improving moods, like depression, and even improving COVID-19 outcomes. 

Two-hundred years ago, we spent about 90% of our time outside, but most recently, the best studies that we have say that we spend about only 7% of our time outdoors. I really do think it is a public health intervention to get people outside and in the sun again. And I want to clarify that you don’t have to be in direct sunlight, exposing yourself unnecessarily to UV rays in order to get the health benefits of the infrared rays. A good rule of thumb is that if you can feel the warmth of the sun, then you’re getting those infrared rays. 

So, I want people to get outside. But I also want them to take the appropriate sun-protective measures: wearing clothing to protect your skin, wearing hats, using broad spectrum, SPF 15, mineral-based sunscreen, avoiding being outdoors during the peak UV hours of the day, so 10 a.m. to 2 p.m. And then, you know, staying in the shade, and specifically around green spaces as much as possible. 

Keyla Holmes is the Scripps Howard Foundation Emerging Journalists Program intern for the Fort Worth Report. Contact her by email at

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