Sunlight and Health: finding a balance
June 14, 2023
Its mid-June and I have already had my first sunburn of the season even though I put on sunscreen. The day was beautiful, and I was having fun riding my bike, not thinking about reapplying sunscreen after multiple hours of riding in direct sun at mid-day. Throughout the year, our relationship with sunlight is a delicate balance, too much or too little both have serious health consequences. Too much high intensity sun exposure can lead to skin cancer. Not getting enough sunlight can lead to serious health conditions like depression, cardiovascular disease, diabetes, non-skin cancers, and increased susceptibility to respiratory viruses like flu and COVID.
From time immemorial, the sun has bathed our planet in radiation, or photons, and life has had to adapt to its challenges. Earth’s magnetic fields and the ozone layer protect us from the most damaging forms of cosmic radiation. The radiation that does pass through the atmosphere plays a critical role in sustaining life on our planet. Infrared provides warmth. Visible light allows us to see the colors of the rainbow and provides plants with energy to photosynthesize carbon dioxide molecules into sugar, the beginning of all food chains. Ultraviolet light (UV) passes into the skin of animals and causes a form of cholesterol (ergosterol) to photosynthesize into vitamin D. Vitamin D is a hormone that has receptors in virtually every organ system of the body, and its health impacts are still being understood.
People living at a northern latitude greater than 37 degrees (Teton County is at 47.9 degrees) are even more likely to have low levels of ‘the sunshine vitamin’ circulating in blood. Sun exposure while gardening or taking a walk, at regular intervals several days a week can increase vitamin D levels. At the beginning of the spring season, exposing the skin to the sun in small doses allows the skin to adapt, without burning, to sun exposure and reap the benefits of vitamin D.
Our primary source of vitamin D is made by our skin when exposed to sunlight. Sources of vitamin D in foods come from mushrooms grown in natural light, egg yolks and fish, such as tuna, salmon, and cod liver oil. Beginning in the 1930’s, dairy products were fortified with vitamin D to combat Rickets, a condition that caused the growing bones of children to develop deformities. Today, plant milk and orange juice are also fortified with vitamin D and can help get through the dark winter months.
What can you do?
First, you must know your skin type and how your sun responds to sunlight. The more likely you are to develop a sunburn the sooner sun protection needs to be used.
The ‘shadow rule’ is a quick way to determine if you need sun protection. If you are shorter than your shadow UV exposure is low, and less sun protection is needed. If you are taller than your shadow UV exposure is high, and more sun protection is needed.
Another strategy is to check the UV index as a part of the daily weather report. This is a scale ranging from 1 to 11+ that provides guidance on the amount of sun protection needed to prevent sunburn. The UV index also changes throughout the day with the intensity increasing between 11 am and 2 pm, even when it is cloudy.
Physical sun protection is a hat with a brim, sunglasses, and tightly woven fabrics. Chemical sun protection is sunscreen lotion, rather than a spray, with a broad-spectrum SPF of 30 that has not expired and has been stored in a cool location.
Use sunscreen lotion abundantly! A teaspoon of the lotion should be used on the face. For an adult in a bathing suit, it is recommended that enough lotion to fill a shot-glass be used to fully cover the body.
Sunscreen should be reapplied abundantly, every two hours while in direct sunlight. After swimming or sweating, sunscreen should also be reapplied- even if it is water resistant.
Spending time outdoors regularly and protecting your skin when the UV index is high is a great way to improve your overall health and wellbeing- just in case you needed one more reason to go outside!
Credits:
Created with images by foto-select - "Alpine winter landscape. View from the Nebelhorn mountain near Oberstdorf, Germany, on a sunny day." • Pixel-Shot - "Hands of religious man praying outdoors at sunset" • Voyagerix - "Black board with word sun against sea coast" • Viacheslav Yakobchuk - "Three women with different complexion smiling feeling happy" • Savo Ilic - "Alone man walking along a small country road in a misty morning" • Chris Ryan/Caia Image - "Man applying sunscreen to shoulder at sunny summer poolside" • Photocreo Bednarek - "Polarized sunglasses on sunny sky UV protection" • Pixel-Shot - "Stylish little girl on light background" • Yevheniia - "Ski equipment. Men's and women's ski goggles and ski sticks"