Did you know that sunburns are not caused directly by heat but by radiation? They are more like “radiation burns” than “sunburns.” Sunburns are caused by the outermost layer of your skin, the epidermis, absorbing UV radiation, not necessarily by hot weather “burning your skin.” The sun emits UV radiation, but we can’t see or feel it. Rather infrared waves are actually what allows us to feel light, and these do not cause sunburns. UV radiation is the cause. UV radiation is invisible to our eyes, and it is responsible for more than 95% of all skin cancers. However, sunscreens work to prevent through two different processes. There are two different types of sunscreen, chemical and physical. Chemical absorbs and physical reflects.
What is chemical sunscreen?
Chemical sunscreens contain organic chemicals like avobenzone or oxybenzone. Organic sunscreens use carbon-based chemicals, like oxybenzone, avobenzone, and octinoxate, to absorb ultraviolet radiation, turn it into thermal energy or heat, and release it.
What is physical sunscreen?
Physical sunblock sits on top of the skin and reflects the sun's rays. The minerals titanium dioxide and zinc oxide are the main, active ingredients in physical sunscreen. Physical sunscreen reflects UVA, UVB, and visible light.
What are UVA rays?
UVA transmits freely through the Earth’s atmosphere.
UVA rays penetrate deeper into the skin and cause premature wrinkling, age spots, and can also heighten the risk for some skin cancers.The shorter wavelengths of UVA also causes sunburn.
What are UVB rays?
UVB rays have slightly more energy than UVA rays. They can damage the DNA in skin cells directly, and are the main rays that cause sunburns. UVB transmits through to the earth’s atmosphere. The rest is absorbed by ozone.
What is visible light?
Visible light are waves that enable us to see sunlight. New research suggests that this type of light, including blue light, can also cause skin damage. In particular, some studies suggest that it causes or exacerbate signs of aging and hyperpigmentation, particularly melasma.
Why do sunburns happen?
Photocred: Medline plus
Sunburns are a form of radiation burn that affect living tissue, such as skin. Sunburns are caused by an overexposure to UVA and UVB radiation from the sun. UV radiation greatly impacts skin cells by disrupting molecules like DNA. Likewise, your body wants to protect you from this, and your body’s inflammatory response is actually what causes pain.
When UV radiation hits your skin, pigments called melanin absorb it, and they block your DNA from harm. Melanin gives the skin color, and it’s created by cells called melanocytes. Melanocytes distribute the melanin to other cells on the top layer called keratinocytes. When skin cells are exposed to UV, the cells increase melanin production and carry more melanin to the keratinocytes. When the rays penetrated they damage cells, but they can also make skin cells produce free radicals. Free radials degrade the skin by separating the electrons in melanin and DNA molecules.
This degradation cause an inflammatory response within the body. The body sends blood cells to stop the damage. Thes influx of blood causes the hallmark redness of a sunburn. “The warmth of a sunburn generally stems from increased blood flow to the exposed site. Even though the burned skin seems much warmer, it would still be close to 98.6 degrees. Any slight elevation in temperature would be a result of the inflammatory response. (Scientific American).”
Why do sunburns cause peeling?
Sunburns also cause shedding. Even though we develop keratinocytes that get replaced all of the time, they don’t mature properly because of damage. So, they clump up, and peel up together.
This is why it’s important to wear sunscreen and avoid prolonged sun exposure! So, seal in skincare with a favorite sunscreen and don’t absorb too many beams!
Coverphoto credit: stockphotos