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The Skinny on Sun Exposure

Kristin Hall

Medically reviewed by Kristin Hall, FNP

Written by Our Editorial Team

Last updated 8/01/2020

How Your Skin Reacts to Sunlight, and What You Can Do About It

Think of your skin as a kind of storyteller: a smooth tightness along your cheekbones says you slept well last night. Look in the mirror, and little smile lines remind you of the last good joke your partner told you. Or maybe the puffiness under your eyes suggests a recent drama.

What else is your skin telling you?

Unless you’ve been living in total darkness, your skin is almost certainly telling you plenty about sun exposure. How? We tend to think of a tan as evidence of time well spent in Cabo, but sun exposure does more than just darken complexion. According to the World Health Organization (WHO), up to 90 percent of the visible signs of aging (think wrinkles, leathery skin) can be attributed to sun exposure. 

And if that little factoid didn’t send you running for a big, floppy hat, here are some other conditions associated with unprotected exposure to the sun:

  • Melasma: This condition is very common, and often presents as brown to brown-gray patches on the skin, particularly the face. Ladies beware: Melasma seems to take its cues from hormonal changes and is much more common in women than in men. It also rears its head as the so-called “mask of pregnancy” (in case you didn’t have enough to worry about while nurturing an unborn child). 

  • Age Spots: We’ve all seen them, maybe on the back of a grandparent’s hand. Also known as liver spots, these tan, brown or black marks are commonly found in adults over the age of fifty. They’re more prevalent in people of lighter complexion, but anyone can develop them — especially people with increased sun exposure.

  • Rosacea: This condition causes the face to appear reddish, sometimes with visible blood vessels and/or red, pus-filled bumps. According to the Mayo Clinic, rosacea is more likely to affect women in middle age. And yes, you guessed correctly: Exposure to sunlight (as well as other environmental factors) may contribute to periodic flare-ups.

  • Poikiloderma of Civatte: Also known as sun aging, this condition presents as reddish-brown patches on the neck and cheeks. Poikiloderma of Civatte is often asymptomatic, but it suggests a high level of sun exposure, which comes with a whole host of other risks. 

By now you might be thinking: if the skin is a storyteller, it has a disturbing bias toward horror. But don’t fear. It’s very possible to have a healthy relationship with the sun, and a solid understanding of how sunlight works is the first step toward making that happen.

What You Can’t See: Breaking Down UV Radiation  

Before we dive into the mechanics of sunlight (and how it affects the skin), let’s get something out of the way: according to the WHO, “sunlight is critical to human physical and psychological well-being.” In fact, sunlight is essential to the body’s production of vitamin D, which plays an important role in skeletal development, immune function and the formation of blood cells. Take a minute to let all that sink in. Okay, good.

But when we say “sunlight,” what exactly do we mean? In reality, we should be talking about sun exposure more generally. The reason is that the sun’s rays can be divided into several distinct categories: light, warmth and ultraviolet (UV) radiation. The first two categories (light and warmth) are perceptible to us, but UV radiation can’t be seen or felt. This means that exposure to UV radiation is much harder to gauge. Here’s what you need to know:

5 Quick Facts About UV Radiation

  1. No type of UV radiation is safe. 

  2. Midday (between 10 am and 4 pm) during the summer months is peak exposure time for UV radiation.

  3. Children under 18 are at an elevated risk.

  4. Higher altitude often leads to higher levels of sun exposure.

  5. Temperature and cloud cover are not good indicators of UV levels.

Making matters even more complicated, there are two distinct types of UV radiation that reach the earth’s surface: UVA and UVB rays. While both can lead to skin damage and even skin cancer, it’s important to understand the differences, too.

What Are UVA Rays?

According to the WHO, UVA radiation is responsible for 95 percent of the UV radiation that reaches the Earth’s surface and penetrates deeper into the skin. UVA rays cause an immediate tanning effect, as well as gradual aging and wrinkling of the skin. In addition to the sun, many tanning beds give off large amounts of UVA radiation. 

What Are UVB Rays?

Most UVB rays don’t make it to the Earth’s surface, and when they do, they only superficially penetrate the skin. Despite this, UVB radiation causes direct damage to skin cell DNA and leads to more skin cancers than UVA radiation. UVB rays are also the primary cause of classic sunburn, as well as delayed tanning and visible aging.

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Sun Smarts: 5 Preventive Measures to Keep Your Skin Safe      

This information might seem scary and overwhelming, but don’t throw in the beach towel just yet. By following a handful of guidelines, you can significantly reduce the risks associated with extended exposure to the sun. A little bit of common sense will protect you from premature aging and a plethora of ailments, from mild to serious.

1. Avoid Excess Exposure to the Sun

This guideline may seem obvious, but it merits mention. When possible, avoid extended periods of exposure to sunlight, especially during peak hours (10am to 4pm). This doesn’t mean you need to cloister yourself in a musty basement all summer long. Instead, enjoy the sun from the shade of a beach umbrella. When you venture out, wear a wide-brimmed hat and clothes that have an SPF rating of 15 or higher. Looking for a reason to get new sunglasses? Find a pair that offers total (or near-total) protection from both UVA and UVB radiation.

2. Slather on the Sunscreen

This is another obvious suggestion, but when did you last read the instructions on the sunscreen bottle? In case you need a refresher, you should liberally apply broad-spectrum sunscreen (again, SPF 15+) every two hours. Swimming or sweating through a few games of volleyball? Slather it on with even greater frequency. Your skin will thank you later.

3. Check the UV Index

Not all days are created equal when it comes to UV exposure. Be sure to check the UV Index before you head outside, and budget your sun time accordingly. Don’t forget that UVB rays reflect off of surfaces like water, snow and pavement, causing increased exposure.

4. Get Out of [the Tanning] Bed

By now, you’re probably expecting more of the obvious. Well, here it is: If you want healthy skin that doesn’t show signs of premature aging, avoid tanning beds. If you’re determined to achieve that bronzed look, try spray-on (or lotion) tanning alternatives. 

5. Beware Other Sources of Sensitivity to Sun Exposure

Certain products in your skincare and beauty routine may increase sensitivity to sun exposure. Be on the lookout for: 

  • Tretinoin, Benzoyl Peroxide and Hydroquinone 

  • AHAs (alpha hydroxy acids) exfoliants 

  • Perfume ingredients like bergamot, lavender, lemon verbena and musk

Medications like antibiotics, antihistamines and oral contraception can also put you at risk. If you’re unsure about whether you might be at risk of increased sensitivity to sunlight, be sure to consult with a physician before hitting the beach. 

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Counteracting After Sun Exposure: Here’s What You Can Do

Like every other human to set foot in sunlight, you’ve had at least some degree of sun exposure. But don’t fret: there are ways to repair past damage to your skin.

Just by hydrating and eating well (especially foods rich in vitamin A), you’ll be on your way to healthier — and healthier-looking — skin. You might also consider trying prescription creams designed to lighten spots caused by melasma or smooth the appearance of wrinkles

Remember: your skin can tell you stories. When it does, be sure to listen.

Want the skinny on, well, everything else? Check out the blog

This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment. Learn more about our editorial standards here.