Numerous studies have shown that spending time in nature reduces stress, improves thinking and boosts one’s mood.

“We know nature plays an important role in human health, but behavioral health and health care providers often neglect to think about it as an intervention,” said Joanna Bettmann, a professor at the University of Utah College of Social Work and lead author on the study. “We set out to distill some evidence-based guidance for those providers.”

From 14,168 studies that met their initial search criteria, Bettmann and her multidisciplinary research team carefully narrowed their analysis to focus on 45 studies, which included a total of 1,492 adult participants with a diagnosed mental illness. Some of the examined experiences included structured therapeutic interventions, while some involved nature experiences alone. Eighteen of the studies were randomized, meaning the research subjects receiving the interventions/experiences were randomly selected.

The amount of time study participants spent in nature varied from study to study; some participants spent as little as 10 minutes in a city park, while others spent multiple days in immersive wilderness experiences. Some of the included studies utilized interval exposure to nature; shorter time periods, several times a week or a month. Others used longer periods of continuous, immersive nature exposure. Yet, different durations and patterns of nature exposure all produced positive results.

“Ten minutes in urban nature is far less intimidating, expensive and time-consuming for people who do not have the time, resources, interest, community support or equipment to venture into wilderness for days or weeks,” wrote the authors.

Bettmann’s coauthors include Scott Couch and Dorothy Schmalz with the university’s College of Health. Funding for the research came in part from Nature and Human Health Utah, a nonprofit established by Schmalz and other Utah faculty to explore ways to bridge the gap between nature and health.

“The relationship between nature and mental health is all over the place. The interventions vary from study to study, and the outcomes therefore are also all over the place,” said Schmalz, a professor who chairs the Department of Parks, Recreation & Tourism. “The work that Joanna did here in bringing it all together and culling through it and really figuring out what the overall message seems to be is an incredibly valuable contribution to understanding what this connection is.”

And what better place than Utah to put this knowledge to work, figuring out how the natural environment affects human health and wellbeing.

“Here we are surrounded by all these extraordinary natural resources,” Schmalz said, “and having this kind of knowledge to work nature into behavioral and mental health can help make Utah a place that’s known for taking advantage of the outdoors to be healthy mentally, physically and emotionally.”

The analysis indicated that water-based outdoor spaces — rivers, lakes, oceans — and camping, farming, and gardening activities had the greatest positive effect. Urban nature, mountains and forests also offered significant effects.

“All of these different types of outdoor spaces delivered positive results, which underscores the importance of preserving green spaces in our natural and built environments,” Bettmann said.

Additionally, regardless of the type of diagnosed mental illness, nature exposure showed statistically significant short-term improvements on mental health symptoms. The positive effects of nature appeared even greater for those participants diagnosed with mood disorders, such as depression or bipolar disorder.

According to the World Health Organization, one in eight people has some form of mental illness, notes the analysis. The cost of mental illness on overall quality of life, as well as its economic impact, makes it important to identify and promote affordable and accessible mental health supports outside of conventional facilities.

“Going for a short walk or taking a camping trip should not necessarily be thought of as a replacement for other therapeutic or clinical interventions,” Bettmann cautioned. “Rather, we should consider time in nature as an inexpensive, widely-available resource to support adults’ mental health and overall well-being.”