Photography by Geneviève Caron Image by: Photography by Geneviève Caron
You only need a small amount of UVB exposure for your body to make vitamin D, and most people get enough through everyday exposure, says Dr. Sonya Cook, MD, a Toronto dermatologist. In the summer, if you're outside for even a few minutes, you'll get enough vitamin D. From October to April, supplement with 1,000 IUs of vitamin D daily.
SPF stands for "sun protection factor" and is a measure of a sunscreen's ability to prevent UVB damage. But SPF doesn't measure UVA protection. Always look for sunscreen labelled "broad spectrum," which means it offers protection against both UVA and UVB.
What is a tan?
A tan is the body's response to skin cell damage from UV rays—the skin produces more pigment (or melanin) in order to protect itself from further UV which can cause mutations that lead to skin cancer.
What is a sunburn?
Too much UVB exposure can damage the DNA in your skin cells so badly that the cells die. The skin becomes inflamed, red, painful and warm due to increased blood flow to the area as it tries to heal. Unfortunately, you can't do anything once you've suffered the burn, and your risk of melanoma — the most serious form of skin cancer — doubles if you've had five or more sunburns in your lifetime.
UVA and UVB
UVB: Ultraviolet B (or short-wave) rays directly damage the DNA in your skin cells and are the dominant rays responsible for sunburns.
UVA: Ultraviolet A (or long-wave) rays penetrate deeper into the skin than UVB and produce free radicals that can damage your DNA. UVA rays cause your skin to tan and lead to wrinkles, sagging, yellowing and photoaging. Long-term exposure causes damage to the basal layer (the deepest layer of the epidermis), where most skin cancers occur.
How to protect your skin?
"The purpose of sunscreen is to allow you to enjoy outdoor activities while reducing the risks of sun exposure," says Dr. Cook. "It should not be used to lie in the sun all day. If people stay out in the sun longer (out of a false sense of security), they will get more UVA exposure and actually increase their risk of skin cancer."
The two most common non-melanoma skin cancers—basal cell carcinoma and squamous cell carcinoma—are directly correlated with long-term exposure to the sun's rays.
For more advice on skin protection, learn about the 5 dangers of tanning beds.
|This content is vetted by medical experts |
|This story was originally titled "Skin" in the June 2014 issue.|
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