Our lives literally revolve around the sun. While there wouldn’t be life on Earth without it, the sun and its infinite energy is a force we must treat with both respect and caution. In this guide, we’ll learn more about we'll learn more about the invisible rays that are part of the energy that comes from the sun known as ultraviolet (UV) light. In particular, we’ll break down the differences between two types of UV rays that affect human skin: UVA versus UVB rays.
The sun emits a broad spectrum of radiation toward planet Earth. We can feel infrared rays — those are the ones that provide warmth. What we don’t feel (until it’s too late) are ultraviolet rays. While most gets absorbed by the atmosphere, UVA and UVB do break through and, if we don’t take precautionary measures, they can affect the cellular structure of our skin.
In technical terms, UVA rays have a longer wavelength, which affects our skin over time. They are associated with skin aging. UVB rays, on the other hand, have a shorter wavelength and are associated with skin burning and skin damage. That time you fell asleep by the pool and woke up looking like a lobster? You can thank UVB rays for your painful souvenir. Despite their differences, both UVA and UVB rays can have carcinogenic effects on the skin.
While less intense than UVB, UVA rays penetrate the deeper layers of your skin. Prolonged exposure can cause genetic damage to cells, accelerating skin aging and increasing the risk of skin cancer. UVA makes up most of the UV radiation reaching Earth, meaning we’re all exposed to it whether we’re inside or outdoors. To mitigate the long-term effects of UVA exposure, dermatologists now recommend applying broad spectrum sunscreen as part of your daily skin care routine.
UVA rays affect our skin in multiple ways. Here are the key risks associated with overexposure to UVA:
While UVB radiation makes up only 5% of the UV rays from the sun, it packs a punch. UVB is the shorter wavelength, high-energy form of radiation that damages the outermost layers of the skin within minutes of exposure — especially between the hours of 10 a.m. and 2 p.m., when the sun’s rays are strongest.
Here are the key risks associated with overexposure to UVB rays:
Skin damage. UVB rays affect the outer layer of your skin and, over time, can cause premature aging. In the short term, they cause tanning and sunburn.
Blistering and Peeling. UVB rays can cause a serious condition called blistering. This is when fluid fills up space between different layers of skin and eventually dries up and sheds, resulting in “peeling.” Keep in mind that just two blistering sunburns can double your lifetime risk of melanoma.
Skin cancer. Excessive UVB ray exposure increases your risk of getting skin cancer in the form of basal cell carcinoma and squamous cell carcinoma. It can also cause a serious type of skin cancer called melanoma, which originates in the cells (melanocytes) that make our pigment and gives our skin its color.
We’ve talked a lot about the potential hazards of UVA and UVB rays, but these invisible wavelengths also provide some health benefits. Small doses (no more than 10 minutes) of UVB ray exposure can help skin cells produce vitamin D3 — important for muscle and bone health.
In addition, both UVA and UVB rays are used in treatments for certain skin conditions. Called “phototherapy,” it’s a form of light therapy prescribed for cases of skin ailments like psoriasis, eczema and vitiligo. It can also be prescribed for rickets, a condition in children where bones grow weak due to Vitamin D deficiency.
To be clear: UVA and UVB rays are beneficial only in the smallest doses and you should continue to take preventative measures to minimize your skin’s exposure to the sun. Here are a few tips to ensure your chances of skin damage or skin cancer are at a minimum:
Both UVA and UVB rays are capable of damaging your skin and causing cancer. UVA rays affect the deeper layers of our epidermis over a long period of time, while UVB rays are largely responsible for top-layer “burns.” Bottom line: use broad-spectrum sunscreen to ensure you’re mitigating the harmful effects of both forms of UV rays.
It’s widely established that UVB rays affect our skin at the cellular level and are more directly connected with cancer-causing genetic mutations. However, since 95% of the rays that reach us are UVA rays, overexposure to UVA over long periods of time can contribute significantly to the risk of developing skin cancer.
Mineral sunscreens or zinc-based sunscreens reflect the sun’s harmful rays. Non-mineral sunscreens (made with active ingredients like Avobenzone, Octocrylene, Octisalate and Homosalate) absorb most of the sun’s harmful rays before they can cause damage to the skin.
UVB is the main source for producing vitamin D since it affects our skin at the cellular level.
If you’re wondering how to treat baby sunburn, don’t worry, we’ve got you covered. Babies have sensitive skin, and it’s super important to soothe that burn ASAP.
Skip the screen—not a big deal, right? Ummm... We all know we’re serious about the screen around here, but you might be surprised to find out why. ‘Cuz it’s not just about the risk of getting a burn (although we really, really hate that).
