Skin cancer is the most common form of cancer in the United States. According to the Women’s Dermatologic Society, more than 1 million new diagnoses are made each year. Sun exposure is the leading cause of skin cancer. Sun exposure also can cause powerful damage to skin–wrinkling, aging and spotting. Sunblock (also known as sunscreen) can protect your skin by absorbing or blocking harmful solar rays.
All sunblocks have a Sun Protection Factor (SPF) rating. The SPF rating indicates how long a sunscreen will work for an individual. You can multiply the SPF by the time it takes your skin to sunburn. For example, if it takes 10 minutes to get sunburned, a sunblock with SPF 15 will protect for 150 minutes. If you don’t know how long it takes to get a sunburn, assume it’s about 10 minutes.
Types of Radiation
There are two types of solar radiation. UVA rays do not usually cause sunburn, but exposure can result in long-term skin damage, such as wrinkling and age spots. UVB rays cause sunburn and are a main cause of skin cancer.
Chemical sunblocks absorb harmful UVA radiation before it can damage skin. Physical sunblocks reflect UVA and UVB rays from the body so they cannot reach the skin. Broad spectrum sunblocks combine several ingredients to block the widest range of UVA and UVB rays. The American Association of Dermatology (AAD) recommends using broad spectrum products with an SPF of 15 or more. Many dermatologists recommend sunblocks with SPF of 30 or more, especially for people with fair hair and light skin.
Check the label of sunblock products before buying. Look for those that protect against UVA and UVB radiation. Apply sunblock 15 minutes before sun exposure to allow a protective covering to develop on your skin. Reapply it every two hours or after getting wet. Apply sunblock more frequently when sweating.
No sunblock provides complete protection from the sun. Try to avoid sun exposure between 10 a.m. and 3 p.m. when UV radiation is strongest. If you’re planning to work outdoors or spend extended time in the sun, try to wear a hat and sunglasses, along with long-sleeve shirts and long pants.
Even regular sunblock users should conduct skin self-examinations every few months. Look for moles that have changed shape or size, itches, or bleeds. Other warning signs include sores that do not heal, growths with curled edges, scaly skin patches, depressed lesions or waxy-feeling skin. The AAD has a step-by-step guide to conducting skin self-exams.