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  • Niki Randolph MS, CISSN

The Good and The Bad of UV Exposure

Most of us are used to hearing about the damaging effects of too much sun, but are you aware of the significant health benefits associated with moderate UV exposure?

July marks UV (ultraviolet) safety month and it’s important to be aware of both the good and the bad that can come from sun exposure on the bright and beautiful days of summer.

The negative effects of UV radiation are generally a result of overexposure, leading to serious, even deadly, medical conditions including skin cancer, cataracts, and other forms of eye damage. According to the United States Environmental Protection Agency every year the number of new skin cancer diagnoses exceeds that of breast, prostate, lung, and colon cancer diagnoses combined. Fortunately, overexposure to the sun’s damaging UV rays is a risk factor that is largely under our control. Wearing hats, sunglasses, protective clothing, sunscreen, or finding a spot in the shade, are some of the ways you can protect yourself and your family from UV radiation while still enjoying the outdoors.

Undoubtedly, overexposure to UV sunlight carries significant risk and precautions should be taken to minimize the harmful effects. However, moderate sun exposure also results in a number of health benefits including stronger bones, a healthier immune response, improved mood and better sleep. These benefits are mostly attributed to vitamin D3 and serotonin production as a result of exposure to ultraviolet light. Let’s take a closer look.

Vitamin D – The Sunshine Vitamin

Vitamin D3, also known as the “sunshine vitamin”, is an essential nutrient (actually a hormone) that promotes calcium absorption and is needed for bone growth and bone remodeling. It also plays a critical role in a number of physiological processes including immune function, cardiovascular function, helping balance thyroid hormones, and the reduction of inflammation. The sun is our best source of vitamin D which is synthesized using cholesterol in the skin following UVB exposure, and then activated in the liver and kidneys. We only get about 10% of vitamin D from food because there are very few naturally occurring dietary sources.

Surprisingly, vitamin D deficiency is a widespread epidemic and may be a result of various factors, one of which is decreased and irregular exposure to sunlight. The good news is, it only takes a short amount of unprotected UV exposure to synthesize adequate vitamin D. According to the Vitamin D Council, approximately half the time it takes for your skin to burn is all that is needed. This will be different for every person and depends on the time of day, where you live in the world, the color of your skin, and the amount of skin exposed, but if you’ve ever had a sunburn this should be easy to figure out.

Serotonin – The Feel-Good Hormone

Serotonin, also known as the “feel-good” hormone, is a neurotransmitter found predominately in the gut but is also located throughout the central nervous system, and in blood platelets. It is made from an essential amino acid called tryptophan that is found in foods like bananas, plums, pineapple, nuts and seeds, cheese, milk, chicken, and turkey.

Serotonin helps us feel calm and focused. It gives us a feeling of well-being. When we have too little, we can start to feel low energy and moody or blue. UV exposure is thought to play a role in the production of serotonin so when the seasons change and the days get shorter and darker, many individuals experience a worsening of mood and anxiety symptoms.

Sunlight plays a role in serotonin production in both the eyes and the skin. UVA exposure triggers serotonin production in the brain via photoreceptors in the eye which is why a getting a little bit of sunshine without the use of sunglasses can improve mood. In addition to the eyes, all of the machinery necessary to make serotonin is present in the skin and it is activated by exposure to light.

There is no denying that the risks associated with too much sun and repeated sunburns outweigh the benefits…too much being the key part of this statement. There’s also no denying that moderate UV exposure has valuable health benefits, including improved mood, and increased vitamin D production that is critical to a variety of physiological functions.

So, before you lather on the sunscreen, covering yourself from head to toe, consider taking a 15-minute walk with a hat. Take advantage of the early summer sun by ditching the sunglasses and sunscreen for a short period time without putting yourself at increased risk of damaging UV overexposure.

Curious how optimizing your vitamin D levels and serotonin production can influence your physical and mental health? Let’s talk!


1. Baggerly, C. A., Cuomo, R. E., French, C. B., Garland, C. F., Gorham, E. D., Grant, W. B., et al. (2015). Sunlight and Vitamin D: Necessary for Public Health. Journal of the American College of Nutrition, 34(4), 359–365. doi:10.1080/07315724.2015.1039866

2. Gupta, A., Sharma, P. K., Garg, V. K., Singh, A. K., & Mondal, S. C. (2013). Role of serotonin in seasonal affective disorder. European Review for Medical and Pharmacological Sciences, 17(1), 49-55.

3. Sansone, R. A., & Sansone, L. A. (2013). Sunshine, serotonin, and skin: a partial explanation for seasonal patterns in psychopathology? Innovations in clinical neuroscience, 10(7-8), 20–24.

4. U.S. Department of Health and Human Services, National Institutes of Health, Office of Dietary Supplements. (2016). Vitamin D. Retrieved from

5. Vitamin D. (2017). Retrieved from

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