Why Sunlight Is Nature’s Antidepressant

Experts are finding that strict sun avoidance is counterproductive.

Illustration by Sunny Lo/The Epoch Times

People are often surprised to discover that Dr. Katie Rodan—a dermatologist—is an avid sun seeker.

“My little secret is I love the sun!” Rodan told The Epoch Times. The former chief resident in dermatology at Stanford University School of Medicine swears by sunscreen but loves the sun because it boosts her mood and helps her sleep better.

“The sun increases feel-good chemicals, like serotonin and dopamine, and helps regulate the body’s internal clock, known as the circadian rhythm,” she said.

For decades, public health messaging urged people to avoid the sun. Now, experts like Rodan are finding that strict sun avoidance is counterproductive, not only to our physical health but also to our mental well-being.

Nature’s Antidepressant

A powerful star and Earth’s largest source of energy, the sun is not our enemy. Sunlight has been called a “natural antidepressant” because it influences neurotransmitters, via the brain and eyes, to elevate mood.

Sunlight boosts your brain’s serotonin levels by cueing cells in the retina, a thin, light-sensitive layer of tissue at the back of the eye. It also helps regulate body temperature. When we don’t get enough of it, the body has to work harder to compensate, which can come at the cost of mood-stabilizing brain chemicals.

There has been a noticeable shift in public health messaging about the sun, according to Phillip Lowe, a clinical psychologist at Kaiser Permanente.

“There is new evidence that natural daylight is preferred over artificial light therapy,” he told The Epoch Times. Natural light is believed to be superior to artificial light because it provides a more accurate and balanced color spectrum and naturally regulates the circadian rhythm.

Research now links daylight exposure to lower risks of depression, better mood, and improved sleep. A study published in the Journal of Affective Disorders linked greater time in outdoor light with a lowered likelihood of major depressive disorder.

Vaibhav Diwadkar, a professor of psychiatry and behavioral neurosciences at Wayne State University in Michigan, takes it a step further: He advocates combining sunlight with movement rather than passive sunbathing. “The best thing for our mental/physical well-being is a combination of getting sun and movement. That’s a win-win,” Diwadkar, who makes a daily dog walk part of his routine year-round, said. “The key is to make it a habit.”

Vitamin D and Sleep

Modern screen-heavy, sedentary lifestyles work against our bodies’ biological need to be outdoors.

“Humans are not meant to spend the majority of their day inside under artificial lights,” Lowe said.

Before the Industrial Revolution, people spent the majority of their lives outdoors, often working the fields from sunrise to sunset. Today, we have become an indoor generation. According to data from the Environmental Protection Agency, Americans now spend about 87 percent of their lives inside buildings, and another six percent inside automobiles.

An indoor lifestyle can lead to a deficiency in vitamin D, as vitamin D is produced by ultraviolet B (UVB) radiation. Nicknamed the “sunshine vitamin,” it plays a direct role in brain function and mood. Low levels have been linked to depression.

Dr. A. Gerson Schreiber, a longtime psychiatrist and former medical director and chair of psychiatry for Kaiser Permanente, has watched this understanding evolve over his career. “When  I started practicing, there wasn’t any information about low vitamin D levels being a contributing factor for depressive disorders,” he told The Epoch Times. “Now, treatment for depression includes testing vitamin D levels.”

The body naturally makes vitamin D when the skin is directly exposed to the sun. Most people get at least some of it this way. Vitamin D is created when UVB rays from sunlight convert cholesterol into an inactive form, which travels to the liver and kidneys, where it is further converted into vitamin D.

Sunlight does double duty for sleep, too.

Schreiber recommends 30 minutes of exposure daily, ideally in the morning: It signals the brain to stop producing melatonin and triggers a rise in cortisol, anchoring the sleep-wake cycle. That natural timer supports the deep, restorative sleep essential to mental health.

Early morning sun exposure will also start an internal timer that prompts your body to release the suppressed melatonin roughly 10 to 14 hours later. That’s why many sleep experts agree that natural sunlight is one of the most effective tools for regulating your sleep.

Like low levels of vitamin D, lack of sleep is a contributing factor to depression. Roughly 40 percent of people diagnosed with insomnia also have clinical depression.

The Drawback of Daylight Saving Time

The importance of light to mental well-being is especially apparent when our normal exposure patterns are disrupted.

In fact, mental health experts believe that daylight saving time clock changes can exacerbate conditions such as depression, anxiety, and mood disorders.

This is especially true for people with seasonal affective disorder, a type of depression triggered by changing seasons. Symptoms typically start in the late fall or winter and resolve in the spring.

An analysis by Stanford Medicine published in the Proceedings of the National Academy of Sciences linked daylight saving to higher rates of psychiatric instability. This is attributed to disrupted sleep patterns, which can cause existing mental health issues to worsen.

Even for those without mental health issues, changes in time disrupt circadian rhythms—especially when clocks are set back an hour, which causes the sun to set earlier. The loss of afternoon sunlight leaves people with less time to spend outdoors, making them more likely to be sedentary.

How to Sun Safely

Even brief exposure to nature has clear protective effects.

Experts such as Lowe recommend spending 10 to 30 minutes outdoors in natural sunlight most days of the week to support mental health and regulate our internal clocks, with morning sun—within the first hour of waking—being optimal.

However, it’s still important to stay protected for skin health, Rodan said.

“You can safely love the sun, and not look weather-beaten,” she said. “You can have it all—if you wear sunscreen, cloudy or not.”

Since overexposure to the sun can increase the risk of skin aging and skin cancer, she recommends applying sunscreen, especially to the face. Just 25 percent of your body exposed to the sun can provide the health benefits, she said.

She recommends using SPF 50, mineral-based, broad-spectrum sunscreen and wearing hats or visors.

Rodan also pointed out a regulatory quirk worth knowing: The United States regulates sunscreen as an over-the-counter drug, whereas Europe classifies it as a cosmetic. This is why more European sunscreens have access to advanced UV-filtering ingredients.

A Little Ray of Sunshine

Sometimes the best things in life really are free, including mental health benefits simply from spending time in the sun. Or, as singer John Denver so famously put it: “Sunshine on my shoulders makes me happy.”

The good news is that the mood-lifting rays from the 4.5 billion-year-old yellow dwarf star are readily available this time of year.

The changes that matter most don’t have to be complicated, Lowe said. “Simple low-cost practices like getting morning sunlight, daily walks in green spaces, and screen curfews can make a noticeable difference to our mental health.”