What happens to your brain in nature? The neuroscience explained

Yoho National Park, Field, Canada. (Unsplash/Hendrik Cornelissen) Have you ever felt calmer almost as soon as you step into the woods? Or maybe noticed your busy mind soften as you look out at the sea? We have known for some time, and many of us sense it intuitively, that spending time in nature is good for us. Neuroscience is now enabling us to understand why, and what the brain is actually doing in those moments. I was recently a co-author on a scoping review of the neuroscience of nature exposure, published in Neuroscience and Biobehavioral Reviews, together with colleagues from the Universidad Adolfo Ibañez, Chile, and Imperial College London, U.K. We reviewed 108 peer-reviewed neuroimaging studies on nature exposure and we found a consistent picture. When people spend time in natural settings (or even view pictures of the outdoors), the brain tends to show signs of reduced stress, lighter mental effort and better emotional regulation.
Increases in alpha and theta waves Many of us live in environments that keep the brain on alert through traffic, screens, noise, crowding and constant decision-making. And while cities are awesome human creations, they place heavy demands on our attention and stress systems. The noise, lights and movement on a city street can be exhausting for our brains. (Unsplash/Howei Wang), CC BY

Nature, by contrast, seems to offer a very different kind of input, and the brain responds accordingly. One of the strongest findings comes from electroencephalogram (EEG) studies, which measure electrical activity in the brain. Across many experiments that we reviewed, natural settings were linked to increases in alpha and theta waves. These are often associated with relaxed wakefulness. Studies also often found decreases in beta activity, which is more closely related to active effort or cognitive load. Put simply, the brain looks less “overworked” in nature. But that doesn’t mean that it becomes passive or sleepy. We could understand it more as shifting into a mode of attention that is gentler and less effortful. For example, watching leaves move, listening to water or noticing changes in light engages the mind in a different way that a crowded street or a stream of notifications does. Some studies suggest these effects can happen quickly. In several EEG experiments — both in the real world and virtual reality — changes showed up within a few minutes, sometimes even as little as three minutes. Longer exposure often produced stronger effects, especially once people spent around 15 minutes in a more immersive setting. Reduced activity in the amygdala We also reviewed studies using functional magnetic resonance imaging (fMRI). These measure changes in blood flow linked to neural activity, allowing us to see which regions become more or less active. One interesting finding was a reduced activity in brain regions involved in stress and rumination after time in nature. The amygdala, which helps detect threats and responds to stress, becomes less active after natural exposure. So does the subgenual prefrontal cortex, a region linked to repetitive negative thinking. Other fMRI work points to changes in networks involved in attention and self-related thought, including parts of the default mode network. These regions are involved in self reflection, mind wandering and what we could call “the background stream of inner experience.” In natural contexts, they reorganized in ways that supported a calmer and less scattered mental state. A cascade of natural effects Looking across the 108 studies, we found a broadly consistent pattern, which we summarize as a cascade of effects through which nature may influence the brain. First, natural settings are often easier for the brain to process. Their shapes and rhythms frequently follow fractal patterns, like those seen in coastlines, leaves and clouds, which the brain appears to process efficiently. This may reduce sensory and perceptual load. As that happens, stress-related systems begin to settle and the body can shift out of fight-or-flight mode. Attention may then become less effortful, and emotional processing more stable. We describe this as a pathway linking perception, stress regulation, attention and self-related processing. Could nature shape your brain anatomy? Beyond the immediate effects of exposure, there is also evidence that nature may shape the brain over longer timescales. Structural MRI studies suggest that living in greener areas is associated with differences in brain anatomy, including greater grey matter volume and better white matter integrity in some populations. These studies are mostly correlational, so caution is needed. They cannot prove that nature alone caused those differences. But they do raise the possibility that small restorative effects, repeated over months and years, may accumulate in ways that support cognition and resilience. So when time outdoors makes you feel lighter, clearer or less caught in your own head, know this feeling is worth trusting. Your brain seems to be changing state. And perhaps understanding a little more about how nature works on us, and how we in turn relate to it, can also help us protect it. Caring for nature is also a way of caring for ourselves and for each other.

Mar Estarellas does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.