SUN, SKIN HEALTH

Should You Wear Sunscreen Inside?

by Christine Yu January 14, 2023

Warm weather is perfect for lazy afternoons at the park — or for busy hours inside spent gazing longingly out the window, if you work for most of the week.

But being stuck indoors when the weather is beautiful comes with one definite upside: You spend less time in the sun's harmful rays. So, can you pack away your sunscreen when you stay indoors, or should you wear sunscreen inside?

The truth is that even if you roll out of bed and head straight to your couch, you shouldn't skimp on the SPF. Here's the science behind why you still need sunscreen inside the house.

Skin Aging UVA Rays Can Penetrate Glass

Before you head outside, you most likely know the drill: Lather up before those pesky rays have a chance to burn you. So, why should you wear sunscreen inside? After all, your home's walls, roof and windows seem to do a pretty good job of keeping you from getting a sunburn.

As it turns out, that's no guarantee of sun safety. While windows filter most UV rays, they don't offer protection from all of them. Standard glass blocks UVB rays, the type of UV rays that cause sunburns, but not UVA rays.

UVA rays — the ones responsible for speeding up signs of skin aging, such as fine lines, wrinkles and sunspots — can penetrate the glass. UVA rays penetrate deeper into your skin than UVB rays, but both increase your risk of skin cancer. If your favorite reading nook is a sunny corner of your home, you're exposing your skin to UVA rays.

The same principle applies to car, train and airplane windows, too. While your car's front windshield is treated to filter most UVA rays, the rest of the windows in your car aren't, leaving you exposed. Nabbed the window seat on an airplane? UV light is even more intense at higher altitudes.

Plus, UVA light is present 365 days a year, even when the sun is hiding behind rain clouds. And don't forget that sun damage accumulates over time — it makes sense to play it safe, even if you plan to spend the entire day indoors.

How to Wear Sunscreen Inside the House

When you reach for a sunscreen to prep for a day indoors, follow the most important rule from the American Academy of Dermatology: Apply a broad-spectrum sunscreen that offers an SPF of 30 or higher every day. Here are a few other tips:

Go for a two-in-one option. If you're going to be inside all day, consider using a facial moisturizer with SPF. You'll be less likely to skip sun protection if it's already built into your moisturizer.
Reapply often. If your workspace is next to a sunny window, you'll want to touch up your sunscreen regularly, approximately every two hours.
Dress for protection. You can also cover up exposed skin by wearing long sleeves, a shirt with a high neck or long pants so you don't have to fuss with reapplying sunscreen.
Adjust your windows. If your home has lots of windows, the Skin Cancer Foundation suggests applying a UV-protective film to block the dangerous rays in all that beautiful natural light.

While wearing sunscreen inside the house may seem like overkill, as time goes on and sun damage starts to reveal itself, your skin will thank you for working so hard to keep it healthy.