Researchers and clinicians say regular morning light exposure can support circadian rhythm, serotonin and dopamine activity, while excessive indoor living may deprive people of biological signals important to mental and physical health.
By yourNEWS Media Newsroom
Americans spend the overwhelming majority of their lives away from natural outdoor light, a pattern researchers say may affect mood, sleep and overall health.
About 87% of life is spent inside buildings, while another 6% is spent in automobiles, according to Environmental Protection Agency estimates. Combined, those figures suggest Americans spend approximately 93% of their time indoors or inside vehicles, leaving only about 7% under the natural light human biology evolved to experience.
Growing research indicates that sunlight may function as a natural mood-supporting tool by influencing serotonin and dopamine activity and regulating the body’s circadian rhythm, the internal clock that governs sleep, alertness and other biological processes.
Dr. Katie Rodan, a former chief resident in dermatology at Stanford University School of Medicine, told The Epoch Times that sunlight helps increase serotonin and dopamine while setting the body’s internal clock for the day.
Morning exposure appears to be particularly important because light received soon after waking provides a strong signal to the brain that daytime has begun.
Many experts recommend spending 10 to 30 minutes outdoors on most days, preferably within an hour of waking, to receive the greatest circadian and mental health benefit.
Vaibhav Diwadkar, a professor of psychiatry and behavioral neurosciences at Wayne State University, said combining sunlight with physical activity may provide greater benefits than simply sitting outdoors.
“The best thing for our mental/physical well-being is a combination of getting sun and movement. That’s a win-win,” Diwadkar told The Epoch Times.
Walking outdoors in the morning can therefore combine natural light exposure with exercise, both of which have been associated with improved mood, better sleep and stronger physical health.
Phillip Lowe, a clinical psychologist at Kaiser Permanente, said public health guidance has begun to place greater emphasis on daylight rather than relying exclusively on artificial light devices.
“There is new evidence that natural daylight is preferred over artificial light therapy,” Lowe told The Epoch Times.
Researchers believe daylight’s broader color spectrum and its timing effects on the circadian system may provide advantages that artificial lamps cannot fully reproduce.
Sunlight also plays a central role in vitamin D production.
An indoor lifestyle can contribute to low vitamin D levels, which have been associated with depression. Researchers have not conclusively established that low vitamin D directly causes depressive disorders, but some clinicians now include vitamin D testing when evaluating patients with depression.
Dr. A. Gerson Schreiber, a former medical director and chair of psychiatry for Kaiser Permanente, said the relationship was not commonly considered earlier in his career.
“When I started practicing, there wasn’t any information about low vitamin D levels being a contributing factor for depressive disorders,” Schreiber told The Epoch Times.
Dr. Charles Garven of the Cleveland Clinic estimated that sunlight accounts for more than 90% of the body’s vitamin D production.
Vitamin D supplements, however, have not consistently produced the broad health benefits once expected.
Science writer Rowan Jacobsen, author of “In Defense of Sunlight: The Surprising Science of Sun Exposure,” told the Harvard Gazette that vitamin D supplements were once promoted as a potential solution for numerous health problems.
Large clinical trials later found little measurable benefit for most conditions, he said, except among people who began with severe vitamin D deficiency.
Sunlight may trigger the production of approximately two dozen compounds in the skin, including substances with possible anti-inflammatory effects, while a vitamin D supplement provides only one isolated compound. Jacobsen cautioned that research into those additional effects remains preliminary.
The timing of sunlight has also entered the national debate over whether the United States should adopt permanent standard time or permanent daylight saving time.
Health professionals have long warned that changing clocks twice each year can disrupt sleep and worsen symptoms among some people with depression, anxiety or seasonal affective disorder.
A Stanford Medicine analysis published in the Proceedings of the National Academy of Sciences modeled light exposure across individual counties and concluded that permanent standard time would provide the greatest health benefit because it preserves more morning light.
The analysis estimated that permanent standard time could be associated with approximately 300,000 fewer strokes and 2.6 million fewer cases of obesity.
Permanent daylight saving time, which has received support in Congress and from President Donald Trump, was projected to provide about two-thirds of that benefit, while shifting more daylight away from the morning hours considered especially important to circadian health.
Researchers and clinicians also emphasize that sunlight exposure should be approached with moderation.
Excessive ultraviolet exposure increases the risk of skin cancer and skin damage. Rodan recommends broad-spectrum, mineral-based sunscreen with an SPF of 50, along with hats or visors.
She said exposing approximately 25% of the body may be sufficient to receive sunlight-related benefits.
Jacobsen has argued that traditional sun-avoidance recommendations were often designed around people with the greatest sensitivity to sunlight and then broadly applied to the entire population.
“Studies have found that sun exposure reduces mortality from any cause by 10 to 30 percent,” Jacobsen told the Harvard Gazette.
That observation does not mean unlimited sun exposure is safe or that sunlight should replace medical treatment for depression.
People experiencing persistent depression, suicidal thoughts or serious sleep problems should seek qualified medical care. Sunlight may serve as a supportive lifestyle measure, but it is not a substitute for therapy, medication or other treatment when those are needed.
For many people, however, spending a short period outdoors in the morning may offer an inexpensive way to reinforce healthy sleep timing, encourage movement and support mood.
The evidence increasingly suggests that natural daylight is not merely part of the environment but an important biological signal that modern indoor life often fails to provide.
Source: Natural News
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