The Surprising Health Benefits of Not Wearing Sunglasses: Sun Exposure, Melanin, and Nitric Oxide

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The other day, Vanessa mentioned that she read that wearing sunglasses can make you more likely to get a sunburn. I hadn’t heard that before. Maybe you have. But, I wasn’t surprised. It seems that we often end up with unexpected consequences of modifying how our bodies have functioned in nature for thousands and thousands of years. Ironically, I’m wearing blue-blocking glasses right now as I type on my computer since it’s after dark and eye exposure to blue light at night compromises sleep. So, it didn’t seem far-fetched at all that blocking sunlight from the eyes during the day could have negative effects either.

I investigated and found the currently available answers to the question: Do sunglasses make you more likely to get a sunburn? I also included some other information that might be helpful to understand. If nothing else, it should give you something to discuss while you lay by the pool, on a boat, or on the beach this summer.

The Science of Sun Exposure

You hardly hear of the health benefits of sun exposure anymore, but there are many. While it’s true that excessive sun exposure can lead to sunburn, skin aging, and even skin cancer, we also need sun exposure for optimal health.¹Skin Cancer Foundation. (2021). Skin Cancer Facts & Statistics. Retrieved from https://www.skincancer.org/skin-cancer-information/skin-cancer-facts/ Sunlight plays a crucial role in our overall health, particularly in producing vitamin D, which supports bone health, immune function, and numerous other physiological processes.²Holick, M. F. (2004). Sunlight and vitamin D for bone health and prevention of autoimmune diseases, cancers, and cardiovascular disease. The American Journal of Clinical Nutrition, 80(6), 1678S-1688S.

However, the interplay between sunlight and our eyes is more complex than you might think. Some researchers, such as Dr. Richard Weller from the University of Edinburgh, have hypothesized that not wearing sunglasses could enhance the skin’s natural photoprotection mechanisms, resulting in potential health benefits.³Weller, R. B. (2013). Sunlight Has Cardiovascular Benefits Independently of Vitamin D. Blood Purification, 35(1-3), 5-11.

The Role of Sunlight in Vitamin D Production

Sunlight, specifically UVB radiation, is most people’s primary vitamin D source. When our skin is exposed to sunlight, a process occurs that converts a cholesterol-like substance called 7-dehydrocholesterol into vitamin D3 (cholecalciferol). This is then converted into its active form, calcitriol, in the liver and kidneys. Vitamin D is essential for calcium absorption, bone health, and proper immune system functioning, among other vital processes in the body.

Melanin Production in Response to UV Radiation

Melanin is a pigment produced by melanocytes in our skin. It serves several purposes, including protecting against UV radiation’s harmful effects. When our skin is exposed to sunlight, melanocytes produce more melanin, which absorbs UV rays and helps prevent DNA damage, leading to a tanning effect.⁴Mitra, D., Luo, X., Morgan, A., Wang, J., Hoang, M. P., Lo, J., Guerrero, C. R., Lennerz, J. K., Mihm, M. C., Wargo, J. A., Robinson, K. C., Devi, S. P., Vanover, J. C., D’Orazio, J. A., McMahon, M., Bosenberg, M. W., Haigis, K. M., Haber, D. A., Wang, Y., & Fisher, D. E. (2012). An ultraviolet-radiation-independent pathway to melanoma carcinogenesis in the red hair/fair skin background. Nature, 491(7424), 449-453.

Photoprotection and Its Potential Benefits

Photoprotection is the idea that our eyes may play a role in signaling our skin to produce melanin in response to sunlight. Although research in this area is still in its early stages, there is growing interest in understanding how our eyes and skin may be interconnected in their responses to sun exposure.⁵Weller, R. B. (2013). Sunlight Has Cardiovascular Benefits Independently of Vitamin D. Blood Purification, 35(1-3), 5-11.

Dr. Richard Weller’s Research on Nitric Oxide

Dr. Richard Weller, a dermatologist and researcher at the University of Edinburgh has studied the effects of nitric oxide, a molecule released in the skin upon exposure to sunlight. Nitric oxide has various functions, including regulating blood pressure, immune system function, and wound healing. Dr. Weller’s research suggests that sunlight exposure may trigger the release of nitric oxide in the skin, providing cardiovascular benefits and potentially other health advantages.

According to Dr. Weller’s research, when the skin is exposed to sunlight, it triggers the release of nitric oxide, which has various health benefits. Some of these benefits include:

1. Lowered blood pressure: Nitric oxide helps to dilate blood vessels, reducing blood pressure and promoting better cardiovascular health.
2. Improved immune system function: Nitric oxide modulates immune responses and protects the body against infections.
3. Enhanced wound healing: Nitric oxide is involved in various stages of wound healing, such as inflammation, tissue regeneration, and remodeling.

Read also: Nitric Oxide and Nitrates: Health and Performance Benefits.

Dr. Weller and other researchers have hypothesized that not wearing sunglasses could enhance the skin’s natural photoprotection mechanisms, leading to increased melanin production. This hypothesis is based on the idea that our eyes play a role in signaling our skin to produce melanin in response to sunlight.

The Potential Benefit of Going Without Sunglasses

Wearing sunglasses can indirectly affect melanin production and potentially increase the risk of sunburn. Melanin has several functions, one of which is to protect the skin from the harmful effects of ultraviolet (UV) radiation from the sun. When the skin is exposed to UV radiation, melanocytes produce more melanin to absorb the UV rays and protect the skin from damage, which leads to a tanning effect.

Sunglasses block significant UV radiation, protecting your eyes from damage. However, they can also indirectly affect your body’s response to sunlight. When you wear sunglasses, your eyes perceive less light, and your body may interpret this as being in a less sunny environment. As a result, your body might not send the same signals to produce melanin in response to sunlight.

The lack of melanin production could potentially lead to an increased risk of sunburn, as your skin may not have the same level of protection against UV radiation. Additionally, people wearing sunglasses might feel more comfortable staying in the sun for extended periods, further increasing the risk of sunburn and other sun-related skin damage.

Interesting, huh? I’ll continue to wear them when I drive since it makes it easier to see, but this summer, I will try to use my sunglasses less and see what happens to my skin. It makes sense that it should tan more and burn less.

Other Benefits of Regular Sun Exposure

Since we’re on the topic of sun exposure, I should mention some of the other benefits of getting out in the sun, specifically concerning hormone production.

Serotonin

Serotonin is a neurotransmitter that is crucial in regulating mood, appetite, and sleep. Exposure to sunlight has been shown to increase serotonin levels in the brain, improving mood and overall mental well-being.⁶Lambert, G. W., Reid, C., Kaye, D. M., Jennings, G. L., & Esler, M. D. (2002). Effect of sunlight and season on serotonin turnover in the brain. Lancet, 360(9348), 1840-1842. This is one reason why people often feel happier and more energetic on sunny days. Getting adequate sun exposure can be particularly beneficial for individuals with seasonal affective disorder (SAD), a type of depression related to seasonal changes and reduced sunlight.⁷Rosenthal, N. E., Sack, D. A., Gillin, J. C., Lewy, A. J., Goodwin, F. K., Davenport, Y., … & Wehr, T. A. (1984). Seasonal affective disorder: A description of the syndrome and preliminary findings with light therapy. Archives of General Psychiatry, 41(1), 72-80.

Melatonin

Melatonin is a hormone that regulates sleep-wake cycles and is produced by the pineal gland in response to darkness. Exposure to natural sunlight during the day can help regulate melatonin production, improving sleep quality and overall circadian rhythm regulation.⁸Cajochen, C., Kräuchi, K., & Wirz-Justice, A. (2000). Role of melatonin in the regulation of human circadian rhythms and sleep. Journal of Neuroendocrinology, 12(4), 303-317. By getting enough sunlight during daytime hours, your body is better equipped to produce melatonin at night, promoting restful sleep and optimal recovery.

If you’ve ever vacationed somewhere warm and spent the day in the sun, you’re probably familiar with how well you sleep at night. It’s melatonin.

Cortisol

Cortisol is a hormone released by the adrenal glands in response to stress, and it also plays a role in regulating the body’s circadian rhythm. Sunlight exposure can help regulate cortisol levels, with research showing that exposure to morning sunlight is associated with lower cortisol levels throughout the day.⁹Leproult, R., Colecchia, E. F., L’Hermite-Balériaux, M., & Van Cauter, E. (2001). Transition from dim to bright light in the morning induces an immediate elevation of cortisol levels. The Journal of Clinical Endocrinology & Metabolism, 86(1), 151-157. Proper cortisol regulation is essential for managing stress, maintaining healthy immune function, and supporting overall well-being.

Endorphins

Endorphins are natural pain-relieving and mood-enhancing hormones produced by the body. Exposure to sunlight has been shown to increase endorphin levels, leading to feelings of well-being and even a mild euphoria, often referred to as the “runner’s high”.¹⁰Hannuksela, M. L., & Ellahham, S. (2001). Benefits and risks of sauna bathing. The American Journal of Medicine, 110(2), 118-126. Spending time outdoors in the sun can help improve mood, reduce stress, and promote overall mental health.

Summary

When it comes to wearing or not wearing sunglasses, there may be potential health benefits to occasionally going sunglasses-free. Most of us always wear sunglasses when it’s a sunny day, and as it relates to protecting our skin, that might be detrimental. Research, such as that conducted by Dr. Richard Weller, suggests that not wearing sunglasses could potentially enhance the skin’s natural photoprotection mechanisms and promote the release of nitric oxide, which has numerous health advantages, including lowered blood pressure, improved immune system function, and enhanced wound healing.

I’ll commit to wearing them less this summer and see what happens. You might consider doing so as well.

Photo by Jose Mizrahi on Unsplash