Scientists recently studied the physical effects that nature has on your brain.
You know that being outside makes you feel good. You know that walking through the woods does something to you. You know that swimming in the ocean puts you in a better mood. But do you know exactly why? Well, according to a study from last year, being in nature has real, measurable effects your brain.
Recent studies have found links between city living and anxiety and depression, while those living outside urban centers have a much lower risk. This seems to me to be a pretty obvious conclusion to draw–that being in nature is better for your mental well-being than living in a bustling concrete jungle–but science felt the need to prove it.
“Various studies have found that urban dwellers with little access to green spaces have a higher incidence of psychological problems than people living near parks,” wrote Gretchen Reynolds in the New York Times. “City dwellers who visit natural environments have lower levels of stress hormones immediately afterward than people who have not recently been outside.”
So they made the connection and proved it. But the exact reason why spending time outside alters one’s mood for the better was still a little blurry. That’s why Gregory Bratman decided to look into it a little more. Bratman, a grad student at Stanford, previously published a study looking at volunteers who simply walked through a green part of the Stanford campus. He found that “were more attentive and happier afterward than volunteers who strolled for the same amount of time near heavy traffic.” Again, this seems like an obvious conclusion. But his newest study honed in on one particular aspect: brooding. Increased brooding is a good indication of depression.
Because scientists need to make up smarter sounding words, brooding is known as “morbid rumination.” We all do it, and it’s not helpful. Basically, it’s thinking about everything shitty in your life and everything shitty about yourself over and over again. According to Bratman, people who live in cities brood a hell of a lot more than, say, a farm hand. Bratman and his other study buddies (or, since they are scientists, his collegues) looked at the increased amount of activity in the subgenual prefrontal cortex when brooding. When you’re sitting around telling yourself that you suck and your life sucks and everything sucks, your subgenual prefrontal cortex is absolutely firing.
Bratman took 38 people, gave them a questionnaire to find out exactly how much they sat around brooding, then looked at each of their brains. Since more blood means more activity, researchers looked for blood flow in the subgenual prefrontal cortex. Armed with that data, they were able to measure what went on before and after literal a walk in the park, and exactly what it did to the brain.
Half of the volunteers took an hour-and-a-half walk through nature, while the other half walked next to a freeway in Palo Alto. They did their walks alone, with no music or any sort of accompaniment. Afterward, they did the brain scan again and took the questionnaire over.
The results were telling: the highway walkers were stressed and frazzled. Their subgenual prefrontal cortex was still full of blood, and they still had the same score on the quiz. The ones who walked through the tree-lined path had considerably less blood flow to the broody part of the brain and scored much higher on the questionairre–meaning that they felt more relaxed and more at peace with themselves.
So in a nutshell, here’s what scientists figured out: a walk in the park makes you feel better. You already knew that… but now you know exactly why.
