Do You Still Need to Wear Sunscreen If You're Inside All Day? Derms Weigh in

At this point, the importance of applying (and reapplying) sunscreen whenever you're outside has been drilled into your head. But what if you are inside all day? Do you really need to wear sunscreen indoors? According to the experts, yes. It's equally—if not more—paramount to apply SPF even when you're inside.

Here's why: Sunlight contains ultraviolet (UV) radiation. There are two main types of UV rays on the spectrum, UVA and UVB. UVB rays have a shorter wavelength and are responsible for producing sunburn. UVA (aging) rays are much stronger and are responsible for issues like discoloration, fine lines, and all those other little things we don't like about our skin. Too much exposure can also lead to more severe skin conditions,  including the big C word.

The Problem With UVA Rays 
This means that if you're spending time in a room with a significant amount of access to sunlight—even through glass windows—it will have quite a similar effect as if you were outdoors. "While glass blocks UVB rays, UVA rays can still penetrate," says Deanne Mraz Robinson, MD, FAAD, a board-certified dermatologist in Westport, Connecticut. "UVA rays are primarily known for their role in accelerating the signs of aging by breaking down elastin and collagen, but they also damage DNA in skin cells, producing mutations that can lead to skin cancer."

To further add to the importance of wearing sunscreen indoors, there's another type of light on the spectrum that affects your skin—and this one doesn't come from the sun. "As we continue to spend more and more time indoors, it's important for people to remember that most devices with screens actually emit HEV light, otherwise known as blue light," says Sameer Bashey, MD, a board-certified dermatologic surgeon in New York and Beverly Hills, Calif. "Examples of these include your cell phone, computers, and televisions." This high-energy visible light has been shown to penetrate deep into the skin and result in damage like hyperpigmentation and melasma.

The Amount of Sunscreen Needed Inside 
Now that we all know you should be wearing sunscreen, how muchsunscreen should you wear? "With sunscreen, it's best to get into a habit that doesn't change even when sheltering in place," says Craig Kraffert, MD, a board-certified dermatologist in Redding, California. "People are creatures of habit, so the best idea is to not change one's daily sunscreen habits, despite the current situation."

That being said, wearing a broad spectrum SPF 30 or higher is recommended by the American Academy of Dermatology and is the minimal dosage for protecting against those harmful rays. Make sure to cover your entire face, as well as your neck and hands, on a daily basis as these are the areas most prone to aging.