Facing Sun Damage
Bill McElligott has severe sun damage to the left side of his face from years of driving a truck. The pronounced difference demonstrates that even through a window, the sun can have damaging effects on your skin. In fact, his face will have SPF skeptics lathering up faithfully every two to three hours.
Catching Some Rays
You probably have never returned home from work with a sunburn from sitting next to a sunny office window. This is because windows prevent UVB rays, the rays that give you a sunburn, from reaching your skin. But those who are sun-savvy know that the sun packs a one-two punch. The sun also emits UVA rays, which cause something even nastier: premature aging and skin cancer. Unlike UVB rays, these rays are able to penetrate through windows. So while you may not be getting a sunburn, sitting inside your office does not mean you are safe from the damaging effects of the sun.
Now that you know sunscreen needs to be applied daily, even if you are just headed in to work, let's talk about how to apply it properly. The first application is a given: apply your first layer at least half and hour before leaving your house. Sunscreen rules typically dictate that it should be reapplied every two to three hours or after swimming or sweating. But don't think you'll have to run to the bathroom to reapply your face three times a day. The rule of thumb to follow is: if your makeup needs a touch-up, so does your sunscreen. Otherwise, your sunscreen is intact from the morning and is protecting you from those damaging rays.