There are many UV rays, but the most commonly discussed are Ultraviolet A (Long wave) and Ultraviolet B (short wave) rays. Ultraviolet A (UVA) penetrates your skin more deeply than Ultraviolet B (UVB), and has long been known to play a major part in skin aging and wrinkling, but it does not cause sunburn. UVA rays are quite constant during all the hours of daylight throughout the entire year. It is the dominant tanning ray and penetrates clouds and glass, so you can get tanned and aging skin damage even you are at home laying down by a window or driving a car.
UVB, the chief cause of skin reddening and sunburn, tends to damage the skin’s more superficial epidermal layers. Its intensity varies by season, location, and time of day. The most significant amount of UVB hits the U.S. between 10 AM and 4 PM from April to October. UVB rays help your skin produce vitamin D but do not significantly penetrate glass, so you cannot get Vitamin D by sunbathing on the couch.
When you buy sunscreen, as many of you already know, you need to find the one which protects you from both UVA and UVB. However, sunscreen stops your body from producing natural vitamin D. Vitamin D plays a crucial role in your overall health and well-being including supporting your cardiovascular health, enhancing your muscle strength, maintaining a healthy immune system, keeping your bones strong and healthy, and more.
Getting lots of sun in a concentrated time is more dangerous than steady exposure over time. So sunbathing without sunscreen is not a good idea. In order to have more safe sun exposure for Vitamin D production, go without sunscreen when your exposure to the sun will be limited, such as doing errands or when you will be out for a short period of time. In general, doctors recommend 15-20 minutes of sun exposure for Vitamin D production. Enjoy the sun but don’t burn yourself!!!
Your Body, Your Health, Your Life 