Whether it’s hiking in the woods or camping under the stars, we’ve all experienced how time in the outdoors can clear your mind like no medication or even gym workout ever could. Recent research is now adding scientific weight to what nature writers like John Muir have known for centuries: According to a study from Stanford University, walking in a natural environment for just 90 minutes can ward off negative thought cycles and reduce your risk for developing mental illness.
The study builds on a solid body of research in psychology that suggests natural environments have a restorative, relaxing power on the brain — an effect not found in large, urban settings where mental health issues like anxiety or depression run so rampant.
“Our previous work, and that of others, has shown that mood and memory benefits can come as a result of nature experience,” says Greg Bratman, study author. To dig deeper into just how much nature can improve mental wellness, he and his colleagues asked 38 healthy city-dwellers from the San Francisco Bay area to take a 90-minute walk in either a lush greenspace populated with oak trees and shrubs, or a busy three-lane street with heavy traffic in the Palo Alto area. The participants had no history of mental illness but did have higher degrees of rumination — another word for the everyday pattern of worries and anxiety that get us stuck in our own heads. Less rumination means a lower risk for depression and often, a higher degree of cognitive function.
After comparing self-reports from the individuals and taking neuroimaging brain scans before and after the walks, Bratman’s team found those who walked in the greenspace exhibited not only lower levels of rumination, but also decreased activity in a part of the prefrontal cortex linked to how our brains process and feel sadness, remorse, guilt, rejection — and possibly denote our risk for mental illness.
“Our general, working hypothesis is that nature is providing a positive distraction for urban- and suburbanites,” says Bratman. Researchers have also suggested an evolutionary angle: Being in a natural environment taps into an unconscious part of our selves that are predisposed from ancient times to thrive in natural settings — a happy home we once knew, but now miss, given our urban lifestyles. Another theory posits that natural environments give our concentration and focus — or what we use to pay attention on the subway, street, or intersections — a much-needed break and chance to replenish itself. In other words, our brains can breathe.
Bratman says more work has to be done because of the experiment’s small sample size, and the findings still have to be replicated in other studies. He adds that an exact prescription of how long you have to spend in a nature setting to reap its rewards still remains to be answered. But you’d be hard-pressed to find a more natural way to clear your head. “Our results should not be casually generalized to a one-size-fits-all solution for all individuals — however, the collective body of findings in environmental psychology suggests that it may be important to ensure city and suburban residents get exposure to nature on a regular basis.”