So you’re sitting at home and enjoying a Netflix binge with no intention to go outside. Do you still need to wear sunscreen?

You may think that if you roll out of bed, get in your car and drive to work, where you sit at your desk all day, that you don’t need sunscreen. Or maybe you’re indulging in a lazy Sunday, binge-watching the latest season of House of Cards, and you have no intention of brushing your hair, much less putting on sunscreen.

But is it really the case that you don’t need sunscreen indoors? Or is that a common misconception about sunscreen?

Setting aside the obvious health benefits of getting moving, getting outside and getting exercise, you may, indeed, be harming your skin and upping your rates of skin cancer if you don’t wear sunscreen — even indoors. That’s because while glass effectively blocks UVB rays (the shorter rays that lead to sunburn), UVA rays (the longer rays that penetrate deeper into your skin and are to blame for wrinkles, sunspots and other signs of sun damage) do pass through glass.

“Unfortunately, there is a lot of misinformation out there about the use of sunscreen, leading individuals to avoid its use,” according to Ashley Wysong, MD, MS, assistant professor of clinical dermatology at the Keck School of Medicine of USC and director of Mohs (a new surgical technique) and dermatologic surgery at USC Dermatology of Keck Medicine of USC.

Indeed, “sunscreen is one of the most important tools in preventing skin cancer,” Dr. Wysong states.

So if your desk or prime TV-watching spot is next to a window, chances are you’re getting bombarded with UVB rays. And it’s not just indoors that you have to be vigilant: It’s in your cars too. Studies have shown that, in the United States, sun damage is significantly worse on the left side of the face and left arm than it is on the right side.

While most windshields are treated to protect against UVA and UVB rays, more often than not, the side and rear windows are not. That means if you’re driving an hour each way to work, you’re getting two hours a day of UVB rays (and that’s not counting time at your desk or time actually spent outdoors) if you’re not wearing a broad spectrum UVA and UVB sunscreen.

To be on the safe side, slather that sunscreen on daily, whether you plan to be outdoors or not. Your skin will thank you for it down the line

If you are local to Southern California and are in search of a primary care physician, call (800) USC-CARE (800-872-2273) or visit www.keckmedicine.org/request-an-appointment/ to schedule an appointment.

By: Anne Fritz