The Sun and Us

Now that it is June, the summer heat is beginning to make itself known, at least to me in my town. I feel it on my runs, or when I get into a car that has been sitting too long in the sun. I see the sunlight beaming down on my surroundings, giving the view outside my window more vibrancy than I have been accustomed to in the winter months. Along with the sun’s heat and light, the sun brings with it ultraviolet (UV) rays, which although aren’t felt or seen, still affect us.

 

A little bit about UV radiation

The sun’s UV radiation affects us year-round, but it is the summer weather that has reminded me of it. In the winter, UV radiation is still present, and can be just as high as UV in the summer months, depending on weather conditions. However, UV radiation is generally higher during summertime. This is not due to hotter temperatures – temperature has nothing to do with UV levels – but is because the sun’s rays are more direct in summer months. In the winter, when the sun’s rays come to us at an angle, more of the UV radiation is absorbed into the atmosphere before reaching us. UV levels are also affected by altitude, how close you are to the equator, cloud cover, and time of day. UV levels are measured by the UV Index, with higher numbers on the scale reflecting higher UV exposure.

 

Benefits of sun exposure

Sunlight helps to set our sleep cycles and circadian rhythms. Additionally, the UV radiation from the sun causes our skin to form vitamin D. Vitamin D is important to keep strong bones and muscles. However, too much UV exposure can also have adverse effects on our health. 

 

Sun exposure’s harms

The sun’s UV rays are not without detriment to our health. There are three types of UV rays – UVA, UVB, and UVC. UVC rays are the most harmful, but luckily are completely filtered out by the atmosphere. UVA and UVB rays are also damaging to our skin. UVA rays are the most prevalent, making up 95% of the UV radiation that hits the earth, and causes skin aging and wrinkling. UVB rays, the other 5% of UV radiation that reaches us, damages the skin’s outer layers and causes skin burning. Too much UV exposure leads to our skin losing its elasticity, instead becoming more wrinkled or leathery. Additionally, UVA and UVB rays cause DNA damage to our skin cells. This DNA damage can lead to abnormal skin cell growth – and yes, can lead to the dreaded skin cancer. 

 

How to protect ourselves from the sun

To protect ourselves from harmful UV rays, it is important to use protection against the sun’s rays. This can be done with protective clothing to cover your skin, or with a hat to shade your face. Shade and umbrellas can also provide protection against the sun. Sunglasses protect your eyes, which can also be damaged from UV rays. Additionally, it is important to apply sunscreen when UV levels are high. The CDC recommends putting on a broad spectrum sunscreen (it filters out both UVA and UVB rays!) that has an SPF of at least 15 before going outdoors. And don’t forget to reapply every few hours!

With some precautions, we can all enjoy a summer full of sunshine.

 

References

 

1. 1. Centers for Disease Control and Prevention. (2024, May 3). Sun safety facts. Centers for Disease Control and Prevention. Retrieved June 1, 2024, from https://www.cdc.gov/skin-cancer/sun-safety/index.html 

1. 1. Skin cancer. (n.d.). American Cancer Society. Retrieved June 1, 2024, from https://www.cancer.org/cancer/types/skin-cancer.html 

1. 1. Sun and skin. (2014, July). NIH News in Health, 1-2. https://newsinhealth.nih.gov/2014/07/sun-skin 

1. 1. Ultraviolet radiation. (2021, July 6). Johns Hopkins Medicine. Retrieved June 1, 2024, from https://www.hopkinsmedicine.org/health/conditions-and-diseases/ultraviolet-radiation 

1. 1. U.S. EPA. (2023, October 24). UV index description. United States Environmental Protection Agency. Retrieved June 1, 2024, from https://www.epa.gov/enviro/uv-index-description 

1. 1. UV radiation. (2021, August). Skin Cancer Foundation. Retrieved June 1, 2024, from https://www.skincancer.org/risk-factors/uv-radiation/ 

1. 1. Vitamin D. (n.d.). Cancer Council. Retrieved June 1, 2024, from https://www.cancer.org.au/cancer-information/causes-and-prevention/sun-safety/vitamin-d 

1. 1. World Health Organization. (2016, March 9). Radiation: Ultraviolet (UV) radiation. World Health Organization. Retrieved June 1, 2024, from https://www.who.int/news-room/questions-and-answers/item/radiation-ultraviolet-(uv)