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JMU dietetics professor Jeremy Akers said vitamin D is one of the most important things our bodies require to function and thrive — but most people aren't reaching the threshold they need.

It's getting darker earlier, and cooler weather is becoming more prevalent. With daylight saving time quickly approaching, it’s time to reap the benefits of not only the sun but the outdoors as a whole while we still can. 

Life on Earth has relied on the sun to power its processes for billions of years. Sunlight’s current impact on humans isn’t as great as it was pre-lightbulb and Thomas Edison, JMU psychology professor Jeff Dyche said, since our days don’t end when the sun goes down anymore. Nonetheless, sunlight absorbed in the right amounts offers the same goodness as it did in hunter-gatherer times. 

One of sunlight’s primary benefits comes in the form of vitamin D, JMU dietetics professor Jeremy Akers said. The vitamin — a “fat-soluble” vitamin, meaning it gets stored rather than excreted, he said — helps maintain bone health, control inflammation and improve immune function, among other supports. 

In a time like now, during a pandemic, Akers said vitamin D’s immune system-bolstering quality is as important as ever. But as the days get shorter and colder, Akers said the vitamin can become harder to obtain from the sun, not because there’s less to absorb in colder weather but because the farther the sun is from the Earth in winter, the fewer ultraviolet (UV) rays — where vitamin D originates — reach us.  

This is one of the reasons Akers takes vitamin D supplements — he said it’s the only supplement he takes. 

“I think it's really, really important,” Akers said. “[Vitamin D is] one of the things that we are definitely below recommendations on.”

Akers said going outside for 15 minutes a day when it’s sunny is adequate for obtaining the vitamin. For maximum absorption, he said to go outside in a “tank top and shorts” when possible; but in the winter, vitamin D can also be consumed from fatty fish and egg yolks

Be cautious with your sun absorption

However, there’s a fine line in the benefits of sunlight, Catherine Zeman, JMU academic unit head for health sciences, said. Like any toxin, Zeman said the sun’s rays exist on a “hormesis J-shaped curve,” meaning the light spectrum offers “incredible” benefits in moderation but can be “problematic” if you take in too much. 

Downsides of too much light in today’s digital age frequently arise when we expose ourselves to too much blue light at night, Zeman said. Blue light, one of sunlight’s light ranges, is also the light emitted from our electronics. Zeman said our melatonin production gets zapped in the presence of blue light at nighttime, leading to sleep disorders, and mood and cognition problems from our sleep cycle getting disrupted. 

“When our melatonin levels are supposed to be going up, we tend to watch TV, play video games and mess with our phones,” Zeman said. “Instead of keying down and relaxing and [tuning] everything down, we start keeping ourselves up when we're supposed to be getting into that positive sleep cycle and going into the REM sleep cycle.”

Additionally, Zeman said, along with ideally receiving blue light during the day to align with the sun being out, not getting enough light during the day can be problematic. She said that a typical office is like a “dull, cloudy, mid-winter day,” because office buildings’ light sources don’t cover the full range of the light spectrum — office lights are 100 times lower than the lumens needed during the day, she said. 

Lumens, the measure of light intensity, are what help elevate our serotonin levels in the “wakeful period” of the day, Zeman said. She said our lumen intake should mirror the sun outside: more light during the day and less at night. 

But sunlight absorption isn’t a one-size-fits-all ordeal, JMU graduate psychology professor and licensed professional counselor Debbie Sturm said.

The demarcation of too much versus too little sunlight can be ambiguous and changes from person to person, Sturm said. She said someone who’s of Mediterranean origin can likely handle the sun’s rays of a clear day at the beach better than someone of English or Irish origin. 

“It's good to pay attention to where your comfort is and listen to it,” Sturm said. “Be really knowledgeable and aware of your body and what it needs and what it can do.”

The sun isn’t the only aspect of being outside that can positively affect your well-being. Sturm said that regardless of weather, just being outside in nature for 20 minutes a day can alter your mood for the better. 

This comes as a result of a serotonin boost from “nature connectedness,” Sturm said. Serotonin levels are also increased by sunlight, but Sturm said that even when it’s gloomy, you should still find time to go outside — she said she believes a relationship exists between people retreating inside and the common trope of feeling more down in the dumps during the winter. For this reason, she said to “embrace every season fully.” 

“Nature's benefit isn't just on warm, sunny, sunny days,” Sturm said. “Nature's benefit is nature.”

A 20-minute walk in nature before an exam, Sturm said, increases oxygen flow to your brain and in turn increases recall. But when nature’s light source is shining, other studies have found, intense light therapy might be linked to reduced tissue damage during heart attacks.

“There's a ton of anecdotal evidence that people feel good being outside on a nice sunny day,” Sturm said. “You can see it just walking around on a nice sunny day; people are seeking the time outside.”

One group of people who usually aren’t outside on sunny days are night-shift workers — the job was classified as a possible carcinogen in 2019. Dyche said that because night-shift workers flip their natural circadian rhythms to be awake during the night but sleep when the sun’s shining, many experience gastrointestinal (GI) issues — “gut rot” as it’s called among Naval submariners, he said — because your digestive system also aligns with the rising and setting of the sun. This is in part because receptors in the eye demand we sleep at night and hunt during the day, he said. 

“You can't fool your brain,” Dyche said. “Your brain knows when it's daytime or when it's nighttime.”

As daylight saving time nears, Dyche said, it can also take your brain up to two weeks to get acclimated to less sunlight. He said there’s “not a sleep researcher in the world” who thinks falling back or springing forward the clocks is a good idea because of the jet-lagged effect it creates. 

A potential solution? Making the most of the limited daylight by grounding yourself in nature, Sturm said. 

“The natural world is everything,” Sturm said. “Any harm to the natural world is harm to ourselves.”

Contact Grant Johnson at breezecopy@gmail.com. For more health & wellness content, stay tuned for the “A Wealth of Health'' column every other Thursday, and follow the culture desk on Twitter and Instagram @Breeze_Culture.