Along with warmth, the sun also produces light and an invisible ultraviolet (UV) radiation. UV radiation can cause sunburn, wrinkles, sunspots, cataracts and skin cancer, and probably contributes to macular degeneration. The tan was once a symbol of health, but now has been shown to be the result of exposure to UV radiation.
You can protect yourself from skin cancer and other sun damage by using sunscreen, covering up and wearing sunglasses that block UV rays.
Some UV radiation, however, is important for the body to make vitamin D, which helps in the absorption of calcium and phosphorus. The World Health Organization says that five to 15 minutes of sun on the hands, face and arms two to three times a week during the summer is adequate for this.
Choose a sunscreen that protects against both UVA and UVB rays. Look for the words "broad-spectrum sunscreen" on the label.
Wear sunscreen with a sun protection factor (SPF) of at least 30 whenever you go outdoors. It's best to apply sunscreen about 20 to 30 minutes before going outside so your skin has time to absorb it. You should reapply sunscreen often, at least every two hours, and especially after exercising or swimming.
According to the American Academy of Dermatology, most people don't use enough sunscreen. The average-sized person needs at least one ounce—about two tablespoons—of sunscreen to cover his or her body.
According to the American Academy of Ophthalmology, the UV radiation in sunlight can damage eye tissue.
UV damage to the eye may cause snow blindness, cataracts and macular degeneration. Risk for damage is higher in environments where a large quantity of UV radiation is reflected, such as in snow or on water.
Sunglasses that provide 99 to 100 percent protection from UVA and UVB rays are recommended. Be aware that darker-colored lenses don't always protect your eyes better—a special coating makes the difference. To prevent sunlight from slipping in around the edges, wear close-fitting sunglasses that wrap around.
Studies show the sun exposure is greater when it's reflected by water, snow or concrete, so use sunscreen and wear sunglasses even while sitting under an umbrella.
Here are more guidelines to protect your skin:
Wear a hat with a brim that's at least four inches wide. Baseball caps don't protect your ears or neck.
Wear protective clothing that covers your neck, arms and legs. Fabrics with a tight weave help block sunlight.
Limit the amount of time you spend in the sun between 10 a.m. and 4 p.m.
Have a symptom or a health care concern? Use this library to explore the symptom topics that could help.