Wondering why when you were a kid, your parents told you that playing outside is good for you?

Wondering why when you were a kid, your parents told you that playing outside is good for you? But then came skin cancer and why sun exposure is bad for you, leaving you confused as to what to do. Here’s the inside scoop of what science is saying.

Benefits of Sun Exposure

A well-known benefit of sunlight exposure is its natural ability to boost the body’s Vitamin D supply; most cases of vitamin D deficiency are due to lack of outdoor sun exposure. Unlike other essential vitamins, which must be obtained from food, vitamin D can be synthesized in the skin through a photosynthetic reaction triggered by exposure to UVB radiation. The efficiency of production depends on the number of UVB photons that penetrate the skin, a process that can be hindered by clothing, excess body fat, sunscreen, and the skin pigment melanin. For most white people, a half-hour in the summer sun in a bathing suit can initiate the release of 50,000 IU (1.25 mg) vitamin D into the circulation within 24 hours of exposure; this same amount of exposure yields 20,000–30,000IU in tanned individuals and 8,000–10,000 IU in dark-skinned people.

People can get vitamin D from their diet and supplements, but sunlight is an important source of this essential nutrient. Vitamin D is necessary for key biological processes to take place in the body. Its benefits include supporting healthy bones, managing calcium levels, reducing inflammation, supporting the immune system and glucose metabolism. A Vitamin D deficiency has proven to contribute to increased mortality as opposed to skin cancer.

Various studies have linked low vitamin D levels to diseases other than cancer, raising the possibility that vitamin D insufficiency is contributing to many other major illnesses. For example, there is substantial evidence that high levels of vitamin D either from diet or from UVR exposure may decrease the risk of developing multiple sclerosis (MS).

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Researchers have also noted a link between exposure to the sun and lower blood pressure levels, with reduced death rates from cardiovascular issues. They suggest that exposure to sunlight triggers the skin to release stores of nitrogen oxides, which cause arteries to dilate, lowering blood pressure, and may reduce the impact of metabolic syndrome.

Sunlight helps to boost a hormone in the body called serotonin, AKA the happy hormone.

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Many people who do not get sufficient sunlight tend to suffer from mental health disorders, due to a deficiency of this hormone. Moderately high serotonin levels result in more positive moods and a calm, yet focused, mental outlook. In addition, serotonin is converted to melatonin in the evening so ensuring that you get the required amount of sunlight, will assist in the correct timing of melatonin release. This will ensure that you have a restful night’s sleep and set your circadian rhythm.

Although excess sunlight can contribute to skin cancer, a moderate amount of sunlight actually has preventive benefits when it comes to cancer. According to researchers, those who live in areas with fewer daylight hours are more likely to have some specific cancers than those who live where there’s more sun during the day. These cancers include colon cancer, Hodgkin’s lymphoma, ovarian cancer, pancreatic cancer and prostate cancer.

According to the World Health Organization (WHO), sun exposure might help treat several skin conditions, too. Doctors have recommended UV radiation exposure to treat psoriasis, eczema, jaundice and acne. While light therapy isn’t for everyone, a dermatologist can recommend whether light treatments will benefit your specific skin concerns.

Research studies have revealed preliminary links between sunlight as a potential treatment for several other conditions. These include rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), inflammatory bowel disease (IBD) and thyroiditis. However, more studies need to be conducted before researchers can conclude that sunlight can be a treatment for these and other conditions. Another interesting piece of research by Littlejohns et al. (2014) confirmed the link between low levels of Vitamin D and cognitive decline in Alzheimer’s and dementia patients.

According to WHO, getting anywhere from 5 to 15 minutes of sunlight on your arms, hands, and face2-3 times a week is enough to enjoy the vitamin D-boosting benefits of the sun. Note that the sun must penetrate the skin. Wearing sunscreen or clothing over your skin won’t result in vitamin D production.

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Risks of Sun Exposure

The benefits of sun exposure far outweigh the risks, however, it is worth it to mention that the risks are increased with prolonged sun exposure.

Sunburn is one of the major effects of prolonged sun exposure and it is one of the major contributing factors to skin melanomas. It may also result in wrinkles, leathery skin, liver spots, actinic keratosis, and solar elastosis.

In addition, prolonged sun exposure can lead to eye damage and immune system suppression as well as faster ageing. UV rays can cause the cornea (on the front of the eye) to become inflamed or burned. They can also lead to the formation of cataracts (clouding of the lens of the eye) and pterygium (tissue growth on the surface of the eye), both of which can impair vision.

One last factor to take into consideration is heat stroke and dehydration. Dehydration occurs when more water is moving out of our cells and bodies than the amount we take in through drinking. Our body’s fluid levels become unbalanced, and severe dehydration can lead to death. If you notice your urine is dark yellow, it’s a good sign that you may be dehydrated. Heat stroke may begin as heat cramps, fainting or exhaustion, but as it progresses, it can damage the brain and other internal organs, sometimes fatally. While often seen in adults over age 50, healthy young high school or college athletes often succumb to life-threatening heat stroke while performing strenuous workouts in high temperatures. When combined with dehydration, prolonged exposure to extreme heat causes the body’s temperature control system to fail, resulting in a core body temperature greater than 45 degrees celcius.

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Tips on how to minimize sun exposure risks

1. Avoid going outside when the sun’s rays are more direct, usually between 10am and 4pm, especially if you are fair-skinned and tend to sunburn quickly.

2. If you’re going to be outside for more than 15 minutes, apply sunscreen with a sun protection factor (SPF) of at least 15.

3. Wear a protective hat and shirt.

4. Ensure that you wear sunglasses to protect your eyes.

5. Ensure that you drink enough liquids to prevent dehydration

SO science has two sides, the good and the bad. Whilst the bad aspects of sun exposure can be prevented, the benefits far outweigh the risk. So go outside today, and get some sunshine and you will reap the amazing benefits of sun exposure. Ensure that you follow the protective tips should you decide to spend some extra time basking in the sun!!

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References:

1. Nall, R. (2019). What are the Benefits of Sunlight. [Internet]. Online. Healthline. Available from: https://www.healthline.com/health/depression/benefits-sunlight#

2. Dresden, D. (2020). What to know about the health benefits of sunlight. [Internet]. Online. Medical News Today. Available from: https://www.medicalnewstoday.com/articles/benefits-of-sunlight

3. Felson, S. (2020). Sunlight and your Health. [Internet].Online. WebMD. Available from: https://www.webmd.com/a-to-z-guides/ss/slideshow-sunlight-health-effects

4. David G. Hoel, Marianne Berwick, Frank R. de Gruijl & Michael F. Holick (2016) The risks and benefits of sun exposure2016, Dermato-Endocrinology, 8:1, DOI: 10.1080/19381980.2016.1248325

5. Littlejohns TJ, Henley WE, Lang IA, Annweiler C, Beauchet O, Chaves PHM, Fried L, Kestenbaum GR, Kuller LH, Langa KM, et al. Vitamin D the risk of dementia and Alzheimer disease. Neurology 2014; 83:920-8,http://dx.doi.org/10.1212/WNL.0000000000000755.

6. Van der Rhee HJ, de Vries E, Coebergh JW. Regular sun exposure benefits health. Medical hypotheses. 2016 Dec 1;97:34-7.

7. Moan J, Porojnicu AC, Dahlback A, Setlow RB. Addressing the health benefits and risks, involving vitamin D or skin cancer, of increased sun exposure. Proceedings of the National Academy of Sciences.2008 Jan 15;105(2):668-73.

8. Alfredsson L, Armstrong BK, Butterfield DA,Chowdhury R, de Gruijl FR, Feelisch M, Garland CF, Hart PH, Hoel DG, Jacobsen R, Lindqvist PG. Insufficient sun exposure has become a real public health problem. International journal of environmental research and public health.2020 Jan;17(14):5014.

9. Mead M. N. (2008). Benefits of sunlight: a bright spot for human health. Environmental health perspectives, 116(4),A160–A167, https://doi.org/10.1289/ehp.116-a160.

10. Cronan, K.M. Sun Safety. [Internet]. Online. Nemours Kids Health. Available from: https://kidshealth.org/en/parents/sun-safety.html

11. American Cancer Society. UV Radiation.[Internet]. Online. American Cancer Society. Available from: https://www.cancer.org/cancer/cancer-causes/radiation-exposure/uv-radiation.html

12. NIH. Sunlight. [Internet]. Online. National Cancer Institute. Available from: https://www.cancer.gov/about-cancer/causes-prevention/risk/sunlight

13. Revere Health. (2016). 5 Dangers of Prolonged Sun Exposure. [Internet]. Online. Available from: https://reverehealth.com/live-better/5-dangers-of-prolonged-sun-exposure/

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