Beware of UV's Partner in Crime

"Sun-kissed skin" might sound sexy, but "DNA-damaged skin" doesn't exactly have quite the same charm...

Unfortunately, they're both the same. Getting a light tan means you've gone and damaged the DNA of your skin cells.

We all know the culprit behind tans, sunburns, and skin cancer: ultraviolet ("UV") radiation. But in recent decades, UV's cousin has been getting a lot of press – and that's blue light.

We're told that blue light can disrupt our sleep, cause eyestrain, and possibly even damage our retinas.

As it turns out, blue light isn't all bad... It can lift your mood, make you more alert, and boost your brain's memory function.

Studies show that short-term, low exposure with blue-light therapy can have an anti-inflammatory effect, making it a useful treatment for stubborn skin conditions like plaque psoriasis, eczema, and acne. Plus, a specialized treatment for skin cancer called photodynamic therapy uses blue light.

But as we'll explain, long-term exposure to blue light has a dark side to it – one that's skin deep...

What Exactly Is Blue Light?

The visible light spectrum consists of multiple wavelengths of energy. White light, like you see from the sun and artificial sources of light, is all the wavelengths combined.

But within the white-light spectrum sit different wavelengths that appear as colors. Red wavelengths are the longest, and blue-violet wavelengths are the shortest. The shorter the wavelength, the higher the amount of energy carried by the light. That's why UV and blue light are troublesome. They carry more – potentially dangerous – energy...

Ultraviolet B  is the form of light that's responsible for giving you a sunburn or, worse, skin cancer. Ultraviolet A  rays have longer wavelengths and go deeper into the skin – making it the culprit behind premature aging and wrinkling. And blue light has the next-shortest wavelengths.

You might be able to save your skin from excess UV rays by going inside. But you can't escape blue light indoors... It's everywhere. Not only is it in sunlight, but to a lesser degree, it's also in light emitted from fluorescent and LED bulbs, TVs, computer screens, and, of course, even our precious smartphones. And scientists are concerned about the long-term effects of that constant exposure.

We've talked about the hazards of blue light before, like how all that screen time can mess with your sleep and retinal cells. But as it turns out, your skin might be another reason to think twice about those marathon sessions of binge watching Netflix episodes...

Blue light can start damaging your skin cells in as little as 60 minutes. And long-term blue-light exposure leads to the formation of reactive oxygen species, or free radicals. Too many of these unstable, highly reactive molecules for long periods of time can damage skin cells, cause darkening (or hyperpigmentation), and speed up aging. Plus, blue light activates proteins called matrix metalloproteinases which can break down collagen (the "framework" supporting your skin) and prevent its formation, too. And that can result in signs of premature aging, including wrinkles.

But there are things you can do to protect yourself...

Doc's Solutions for Blue and UV Light

You're going to have to get really choosy about how you spend your time in the light...

Most of our blue-light exposure comes from the sun. So you'll cover your bases by following the same guidelines to not overdo it with UV rays.

Start by checking to see how strong the sun's rays will be in your zip-code area with the UV Index. Most weather websites or smartphone apps have this information. A low UV Index reading of below 2 means you're golden, but you'll want to start taking precautions with readings of 3 or higher, especially if you burn easily.

If you're already out and about and don't have the UV Index handy, "Peter Pan" it... Use your shadow as a rough guide. If your shadow is shorter than your height, that means the sun's rays are at their most intense, and you should take precautions like limiting your outdoor time or seeking shade. You'll typically find a shorter shadow around noon during summer. That's when the sun is at its highest, and its rays don't have to travel very far to reach you.

If you'll be out in the sun for a while, choose a moisturizing sunscreen for your face and any other exposed areas, and apply liberally. You'll want one with zinc oxide, which acts as a physical barrier against blue and UV light, as an active ingredient. (We like a company called Badger for its zinc-oxide sunscreens – you can find them online or at a store near you.) Make sure to follow the label's instructions on when to reapply (generally, every two hours if you'll be swimming or sweating). And buy a fresh tube or bottle if yours is past the expiration date.

If you don't want to deal with the hassle of applying sunscreen all over your body, go with fabric protection. A 2022 study published in Cancers confirmed that fabrics with a high ultraviolet protection factor ("UPF") rating blocked more rays than sunscreens. A UPF rating of 50 is ideal – it means the fabric only lets in one-fiftieth, or 2%, of radiation.

If you're unsure that what you're wearing will protect you from UV and blue light, it all depends on the knit... You'll want to stick with tightly woven, dark-colored fabrics on the thicker side if you're planning on being under the beating sun for a while. Loosely woven cotton and linen sure are breathable and comfy, but they let in all those rays. And light colors might keep you cooler than darker colors, but that's because they absorb less radiation.

Check out Columbia for affordable, lightweight clothing options. Another option, albeit slightly pricier, is Coolibar. Both offer 20% to 25% off your first online order if you sign up to receive their e-mails. One of my researchers swears by Coolibar's cap for jogging outside. It comes with a neck drape, and she admits to looking a little funny with it on. But she likes it better than having to wear sunblock on her ears and neck. (Plus, you can detach the drape if you aren't keen on feeling like T.E. Lawrence from Lawrence of Arabia when ducking into a nearby coffee shop.)

As far as screens and artificial sources of blue light go, the best thing to do is limit your screen time as much as possible. Otherwise, go for physical barriers like an inexpensive pair of blue-light-blocking glasses like these, for example, if you spend a lot of your time looking at a computer monitor. Or go for a screen protector like this one – just make sure to buy the right size for your monitor.

I always turn my screens off about an hour before I go to bed, since too much blue light messes with your circadian rhythm, or your body's internal clock. It's part of my healthy sleep hygiene, which ensures that I get enough high-quality rest each night.

Oh, and don't run off to buy all those expensive "antiaging" creams. Focus on eating those antioxidants – not wearing or slathering them on – to fight oxidative damage.

Foods like berries, spinach, beans, and carrots are packed with free-radical-fighting antioxidants like vitamin C and lutein, for example. They'll not only benefit your skin and eyes, but also the rest of your organs and your whole body.

Instead of buying skin-plumping serums this summer, go for hydrating watermelon. A cup of watermelon equates to about half a cup of water. And, of course, it's loaded with antioxidants like lycopene and vitamin C. I like to sprinkle a little salt on my slices to bring out the natural sweetness. Or, if I'm feeling fancy, I toss some leftover cubes with some tangy feta for the salt element, along with extra-virgin olive oil, red onions, freshly cracked black pepper, and mint.

What are some ways you dodge those extra rays in the summer? Let us know at [email protected].

What We're Reading...

Here's to our health, wealth, and a great retirement,

Dr. David Eifrig and the Health & Wealth Bulletin Research Team
July 6, 2023