It turns out that Mom was right after all. It takes some growing up, humility, and open-mindedness—even if grudgingly achieved—to quit the eye-rolling at things our parents said. For my brothers and me, it was “you need to go outside and play.” What? Why do we “need” to do that?

Whether she was parroting folk wisdom, going on gut instinct, or exercising some mysterious mom super-power, she knew that time outside worked wonders. It could reverse a foul mood, restore energy to a listless pre-teen, or create some serendipitous moment that saved the day. Many of us feel intuitively that time outdoors is, well, good. But now medical professionals and researchers are proving our intuition has merit, pointing to specific health benefits. Moving steadily from the fringe toward the mainstream, “nature Rx” is quickly gaining credibility. Professionals and lay people alike are beginning to understand the profoundly positive impacts of exposure to the natural world.

More than 300 peer-reviewed studies have identified a strong correlation between time in nature and health benefits. Specifically, these studies show that time outside results in lower heart rates, reduced stress, enhanced intestinal and gland activity, and more. Research is revealing time in nature is a factor in lowering hostility and depression while enhancing memory and feelings of awe. Data are also documenting how time in forests boosts “natural killer” (NK) cells in humans. NK cells are a type of lymphocyte that help ward off tumors and fight virally infected cells.

Dr. Robert Zarr, from Washington DC, is converting the research into active patient treatment by “prescribing” parks, literally. He and colleagues have mapped and rated 350 parks for access, cleanliness, level of activity and safety, linking these places to their patients’ Electronic Medical Records (EMR). Zarr can thus quickly connect a patient with a natural place near home, school, or work where they can fulfill his nature prescription.

Importantly, Zarr and others aren’t especially focused on the activities that draw typical outdoor recreationists to trailheads like jogging, bicycling or hiking. Rather, they promote simply being outside in nature.

Dr. Robert Zarr, from Washington DC, is converting the research into active patient treatment by “prescribing” parks, literally. He and colleagues have mapped and rated 350 parks for access, cleanliness, level of activity and safety, linking these places to their patients’ Electronic Medical Records (EMR). Zarr can thus quickly connect a patient with a natural place near home, school, or work where they can fulfill his nature prescription.

He is also the founder and medical director of the nonprofit Park Rx America whose mission is to “decrease the burden of chronic disease, increase health and happiness, and foster environmental stewardship, by virtue of prescribing Nature during the routine delivery of healthcare by a diverse group of health care professionals.” To date, Zarr has provided hundreds of nature prescriptions, and his work is being mirrored by a growing number of health professionals nationwide and internationally.

Importantly, Zarr and others aren’t especially focused on the activities that draw typical outdoor recreationists to trailheads like jogging, bicycling or hiking. Rather, they promote simply being outside in nature. Yes, exercise (whether done inside at a gym or outside in a forest) has proven health benefits, but the nature RX movement makes space for more passive experiences in natural settings.

For example, Shinrin-Yoku¸ Japanese for “forest bathing,” holds that simply spending quiet time in the woods restores balance and feelings of wellness. Studies are backing up the claims, pointing to reduced blood pressure levels, higher endorphin levels, and self-reported feelings of calm and well-being.

The principles behind Shinrin-Yoku originated from observations during Japan’s broad economic shift from agrarian to industrial work. The government began noticing a rise in chronic disease (especially cardiovascular) and began studying whether being divorced from the outdoors was contributing to the trends.

Shinrin-Yoku has inspired a field of “forest therapy” in the United States, actively promoted by the Association of Nature and Forest Therapy (ANFT). The association provides “standards based training and certification for forest therapy guides.” Guides offer individuals opportunities to experience “guided walks” to learn greater mindfulness and openness to nature’s healing powers.

“It seems somewhat universal that people feel good after spending a warm, sunny day in nature, and you don’t have to look very far to get corroboration on those anecdotal indicators,” says Toby Bloom, a national program manager for the U.S. Forest Service and a guide certified by ANFT. “I’d say the thing that most excites me is the fact that stories about nature being good for your health are totally mainstream now.” She emphasizes greater productivity and a general sense of well-being.

Bloom acknowledges many may be skeptical of such health claims. “I think the best way to sway a skeptic is to get them on the forest for a few hours or a full day and see how they feel afterward.” For those who need more scientific proof, she points to a raft of studies.

One of the persistent challenges in broadening access to forest therapy is similar to one that conservation and environmental organizations grapple with daily, namely including disadvantaged or marginalized communities. Barriers abound. For example, National Forests can be notoriously difficult to access for city dwellers. Disadvantaged populations may have a significant awareness gap about the health benefits of simply being outdoors, raising a communications challenge. But none of those are insurmountable.

In Oakland, CA the Center for Nature and Health blends diversity and natural health effects through weekly community walks. I spoke with Mona Koh last fall in Wyoming (where, not surprisingly, she was leading a walk on the Bridger-Teton National Forest). Koh said she helps convene “anyone who wants to come” every Saturday morning in Oakland for restorative time outdoors. “We walk together. We talk. We say ‘good morning’ in every language we know. Our activity stretches across generations, races, languages.”

As Tamberly Conway notes, “From an environmental justice perspective, it’s great to have tools that can show how trees can improve the health conditions in disadvantaged communities.” Conway is a Partnerships, Diversity, and Inclusion Specialist at the Forest Service. She explains that any time in any natural setting is beneficial relative to an indoor-focused lifestyle. This means even small local parks—an important part of Zarr’s approach— provide health-improving opportunities. In other words, one doesn’t need to camp in wilderness to get a therapeutic boost.

Motivated in part by a desire to help historically marginalized communities embrace nature Rx, Conway is training to become a forest therapy guide. She notes, “This work has been life changing. I went on a walk and realized I had never seen anything so powerful. Forest therapy opens you up and increases your intuition. The guide opens the door, but the forest is the therapist.” Today, there are approximately 350 certified guides in the U.S. and ANFT is focused on bringing in more participants from underserved and underrepresented communities.

The recent embrace of the outdoors as a health resource reinforces the role of and rationale for public lands in the U.S. Partnerships are emerging, and the trend appears strong. But there is more work to be done. Public land managers need to ensure the lands they manage are welcoming and accessible to diverse constituencies, and all of us need to broaden our notion of what constitutes a beneficial outdoor experience and what we “need” to access one.

“There is the ‘tyranny of the polar fleece,’” Bloom says. “People think they need the best gear, shoes, equipment or whatever to really appreciate nature, or that they need to be an avid mountain climber or biker or whatever. That is absolutely not the case. Any time you spend in nature, or just lying on your back in the grass looking at trees and plants, that’s time well spent.”

Just ask mom.

National Forest Foundation