The Neuroscience Behind “Touching Grass”
By Kelsey Hurst
The phrase “Go touch some grass” has become integrated into today’s vocabulary, but it doesn’t mean to literally go touch grass—it means that you are out of touch with the world around you. There is research that shows that when we spend time in nature there are measurable changes in your brain. So when you are outside in nature you are not just getting a breath of fresh air. You are rewiring the circuits in your brain in ways that can reduce stress, help you focus better, and even boost creativity!
What happens inside your brain?
A 2015 study published in the Proceedings of the National Academy of Sciences found something remarkable. In this study, participants took a 90-minute walk either through a natural environment with trees and greenery or through an urban setting with traffic and buildings. Researchers used MRI scans before and after each walk to observe brain activity in an area of the brain responsible for rumination–the mechanism behind those repetitive negative thoughts and worries about past and future events. The results showed that those who walked in nature had less repetitive thinking.
There is something special about nature and the way that it alters brain function. While restorative environmental exposure yields cognitive and health benefits, the mechanisms driving these effects are poorly understood. Theta waves are associated with deep relaxation and meditation, while alpha waves occur during calm, wakeful states and support creative thinking. A study examining participants exposed to natural environments found stronger alpha-theta activity in the brain during these restorative experiences.
A comprehensive meta-analysis examining multiple studies found consistent evidence that nature exposure improves cognitive function through these neurological changes as well. Increased nature exposure is associated with reduction in stress markers, heart rate, blood pressure, and improved heart rate variability.
What this means for your daily life
Stress and anxiety can leave our brains in a state of constant worry and spiraling thoughts that will not stop. Nature exposure reduces rumination and anxiety dampens down. A genuine sense of mental quiet creating neurological conditions for better mood regulation and emotional stability. So when your mind won’t stop racing, sometimes the most scientifically sound advice really is to just go outside and touch some grass.
References
Bratman, G. N., Hamilton, J. P., Hahn, K. S., Daily, G. C., & Gross, J. J. (2015). Nature experience reduces rumination and subgenual prefrontal cortex activation. Proceedings of the National Academy of Sciences, 112(28), 8567-8572. https://doi.org/10.1073/pnas.1510459112
Chen, Z., He, Y., & Yu, Y. (2020). Attention restoration during environmental exposure via alpha-theta oscillations and synchronization. Journal of Environmental Psychology, 68, 101406. https://doi.org/10.1016/j.jenvp.2020.101406
Twohig-Bennett, C., & Jones, A. (2018). The health benefits of the great outdoors: A systematic review and meta-analysis of greenspace exposure and health outcomes. Environmental Research, 166, 628-637. https://doi.org/10.1016/j.envres.2018.06.030