Outside Magazine

Thirty-five years ago, a young researcher at the University of Delaware conducted a remarkable study. Having spent his childhood sick with kidney disease, in and out of “gloomy, sometimes brutal” hospitals, Roger Ulrich was interested in finding ways to improve “the environments where patients are treated.” So he sought to test the potential influence of an old friend that had brought him comfort as a child: a solitary pine that he could view through the window by his sickbed. “I think seeing that tree helped my emotional state,” he recalled in an interview decades later.

That small study would give birth to thousands of replications and expansions—and an entire movement in architecture. Ulrich managed to find a hospital ward where, for years, patients had recovered from gallbladder surgery in identical rooms that overlooked either a small stand of deciduous trees or a brick wall. After pouring through nearly ten years’ worth of ward records, Ulrich found that patients with a view of the trees fared far better than the miserable patients with nothing but a wall to look at, even if their cases were identical. Those with a view took fewer painkillers, were rated by their nurses as being in better spirits, and, on average, left the hospital nearly a day earlier than those without a view. What was going on? 

We’ve learned a lot about nature and the brain since then. After Ulrich’s foundational work, more than 100 studies have investigated the potential mental-health benefits of exposure to natural stimuli. From these studies—many of them small, observational, and imperfect—we believe that nonthreatening natural stimuli (as opposed to, say, a nearby lightning strike) can play a profound role in the regulation of our autonomic, or involuntary, nervous system. Natural settings that, to quote Ulrich, are “favorable to ongoing well-being or survival” appear to signal our brains that it is time to take a breather, allowing us to turn down our fight-or-flight system, restore our resources, and approach things that are good for us, like finding food or socializing. Specifically, we have learned that nature tends to result in reduced circulating levels of the stress hormones adrenaline and cortisol and the inflammatory marker immunoglobulin A. It is also associated with lowered blood pressure, improved “affect” (or short-term emotional experience), blunted “perceived stress” after stressful life events, and lower short-term levels of anxiety and depression. We also appear to ruminate less after we’ve spent time in nature, a phenomenon distinct enough to appear as differences in neural activity during brain scans.