Sunday morning, praise the dawning
Getting some sun exposure clearly has its benefits; it increases your vitamin D levels and helps ward off insomnia and the blues. But nobody wants skin cancer, cataracts, wrinkles, sagging skin, and age spots. Most of us know enough to lather on the sunscreen before heading off to the pool or beach, but we may not use it when we’re, say, sitting in the shade for hours under a beach umbrella.
However, between 10 a.m. and 4 p.m., when the sun is at its strongest, you can get a fair dose of ultraviolet rays even when you’re not bathed in sunshine. Ultraviolet A rays, which tan and age the skin and raise skin cancer risk, are strong throughout the day and can reflect off of beach sand and water, exposing you even when you’re in the shade. They can also pass through office and some car windows. Sunburn isn’t a reliable guide to UV exposure. Sunburn-causing ultraviolet B rays are weak in the off-peak hours and don’t penetrate glass or reflect much off of surfaces, so you could be getting high amounts of UVA exposure even if you’re not getting a sunburn.
