Getting Outside May Change Your Brain in a Good Way

It's widely known that spending time outside can be good for your mental health—something that many people discovered they took for granted as they spent more time at home during the COVID-19 pandemic.

While the mental benefit of getting outdoors might be well-known anecdotally, researchers are still trying to understand what happens in the brain to create the effect. Now, a new study finds that this daily habit can alter your brain structure, in a positive way.

German researchers from the Max Planck Institute for Human Development and the Medical Center Hamburg-Eppendorf set out to see how spending time outside affects a person's brain on a day-to-day basis.

The small study, which was published in the World Journal of Biological Psychiatry in July, included six healthy individuals who lived in Berlin. The participants were all working in academia and did not consume excessive nicotine, alcohol, and or drug consumption.

Each participant reported how much they had spent outside in the past twenty-four hours. They also received brain MRIs about twice a week for six to eight months. This occurred between the summer of 2013 to early 2014, when the participants were between the ages of 24 and 32 years old.

Throughout the study, the participants also used a physical activity tracking device and answered questions about their fluid intake.

The researchers found that spending time outdoors was associated with an increase in grey matter volume in the right dorsolateral prefrontal cortex (DLPFC). They hypothesized that factors such as exposure to sunshine, amount of fluid intake, hours of free time, and physical activity, could all play a role in the increase. Researchers have previously associated various psychiatric disorders with a reduction in gray matter in this part of the brain.

"[The researchers] clarified in the results that the magnitude of change seemed to be about 3% for the day," David A. Merrill, MD, PhD, adult and geriatric psychiatrist and director of the Pacific Neuroscience Institute’s Pacific Brain Health Center at Providence Saint John’s Health Center, who was not involved in the study, tells Verywell. "You wouldn't notice the difference if you're just eyeballing the size of the brain, but if you do a quantification is significantly different in terms of the quantified side."

The rapid increase was surprising to researchers. While previous studies have found that physical exercise or cognitive training can lead to a 2-5% increase in grey matter volume, it usually happens over a longer time.

"It is common that longer periods of time spent outside would have a positive effect, so knowing that even short periods can be beneficial is a wonderful surprise," Ernesto Lira de la Rosa, PhD, a New York City-based licensed clinical psychologist and Hope for Depression Research Foundation media advisor, who was not involved in the study, tells Verywell.

More Research Is Needed

While the study's findings are intriguing, more studies need to be done with different populations to see spending time outside would affect their DLPFC. For example, Merrill would "be curious to know [whether the] benefit extends into older age, and individuals at risk for Alzheimer's."

It could also be useful to see if there are differences based on where people live. The researchers of the German study considered that there might be even greater benefits to spending time outdoors for people who live in cities due to air pollution.

In the study's discussion, the authors wrote that "it is well-known that air pollution is oftentimes worse indoors compared to outdoors, when the air is not well-ventilated, which can seriously affect the health of the inhabitant."

The Mental Health Benefits of Being Outside

Researchers have touted the benefits of getting outside for decades. For example, a January 2020 systematic review published in the Frontiers in Psychology journal found that spending time in nature could serve as a buffer for mental health and lower stress in college students.

"There's a lot of evidence that nature walks, time outdoors can actually decrease anxiety and improve mood," Merrill says.

What makes the German study especially compelling is that the evidence provided by the MRI came a short time after participants spent time outside. Merrill says that these findings are "in line with studies that have been done with a subjective report, and here they're showing an objective brain effect of the time outdoors."

Understanding the role that spending time in nature could play in brain structure could also be important for clinicians to consider when working with patients.

"When we can see the parts of the brain that are impacted, it gives us more information for how to tailor interventions that can target specific brain functions," Lira de la Rosa says. "If spending time outdoors positively impacts our mood and the DLPFC, then we can begin to make recommendations for individuals who are diagnosed with mental health conditions, such as depression."

Spending Time Outdoors During COVID

During the COVID-19 pandemic, many people found themselves staying inside to avoid exposure to the virus at the expense of missing out on the many health benefits of spending time outside.

"Since so many people experienced lockdowns, going outside felt like a luxury," Lira de la Rosa says. "I think it is important for people to break up their routines, especially if they spend a lot of time indoors or working from home."

One way that you can spend more time outside is committing to outdoor physical activity.

Ways that you can safely participate in outdoor activities while reducing your risk of COVID include:

• Run, walk, or bike through your neighborhood park
• Take your dog for a walk around the neighborhood
• Hike on local trails
• Participate in an outdoor yoga class
• Work in your backyard garden