Sunlight Through A Window: Damaging Or No Big Deal?

Several days ago, as the R29 beauty team basked in the golden afternoon sunlight that streams through our windows (while working hard, of course), the subject of SPF came up. We suddenly found ourselves a group divided: While we all wear sunscreen in general, some of us don't wear it unless we're going to be outside — the sunlight can't damage you indoors, right? When we said as much, we were instantly chided by our colleagues. You have to wear it every day, no matter what, they insisted.

According to Dr. Bowe, "There's a lot of evidence showing that cumulative, ongoing exposure to low-level UVA rays leads to signs of aging and skin cancer." And, as for our sunlight-through-the-window question? UVA rays can absolutely penetrate glass. She says, "If your desk is near a window and you can see the sunlight on your skin, you're getting exposure." Dr. Bowe recommends using an SPF of 15 if you're going to be inside, and 30 if you're going to be outside.

In the car, Dr. Bowe says that front windshields tend to be made of treated glass that prevents the sun from coming through, but side windows and sun roofs aren't. Often, she says, people who drive frequently get sun damage and skin cancer on their left side.

But, we wondered, surely this isn't all bad. After all, isn't the sun where our vitamin D comes from? And, if UVA rays can penetrate the window, can we ease our seasonal affective disorder through the window as well? Dr. Bowe was quick to point out the error in our logic: "There's a big misconception that you need to get your vitamin D from the sun," she says. "Any amount of sun that can give you enough vitamin D is also enough to give you skin damage." Dr. Bowe suggests we take a vitamin supplement instead.

So, there you have it. When it comes to damage from the sun, you can never be too careful — no matter if you're breathing fresh air or gazing outside from your cubicle.