This post is the second article in weekly five part series exploring the mental health benefits of hiking, from a scientific and a first-hand perspective. The author has asked to remain anonymous, but if you stay tuned for all five articles, you will be amazed and inspired by the ending.

Have you ever seen someone deep in thought pace back and forth? Or, have you ever gone on a walk to “clear your head”? The relationship between walking and thinking is another area of study that speaks to the therapeutic effects of hiking. It’s tempting to think of walking and thinking as two distinct processes. One is a motor function, and one is a cognitive function. Totally different, right? Not exactly.

The high-level structures that make our brains distinctly human evolved while our ape ancestors transitioned from a life on all fours to “bipedalism” – walking on two legs. Our ability to think co-evolved with our ability to walk. It’s not surprising, then, to learn that the processes of thinking and walking are deeply integrated. (1)

You’ve probably directly experienced the intimate relationship between your mind and your step. The cadence of your walk can influence the inner rhythm of your thoughts and emotions, and vice versa. Therefore, you tend to walk faster if you’re excited or angry. If you consciously slow down your step, your level of agitation will naturally fall. (2) In 2019, scientists were able to predict a person’s answers to a depression and anxiety questionnaire by measuring their gait, leading to the proposal that walking may become a valuable diagnostic tool for mental health professionals. (3)

Optic Flow

“Optic flow” provides another lens into the walking-thinking dynamic. As you walk, your eyes make constant lateral movements to continuously update your brain on where you are in space. The tree up ahead “moves” in relation to your gait and gets bigger as you walk towards it, letting you know that you’re getting closer. That’s optic flow in action. As your eyes move to engage with optic flow, the parts of your brain that process your response to threats become quiet. (4) This altered emotional state, in turn, can affect your thought patterns.

EMDR

One of the most popular treatments for PTSD and anxiety disorders is based on the science of walking. In 1987, a psychologist named Dr. Francine Shapiro went for a walk outside. She was preoccupied with “disturbing thoughts” and noticed that, as her eyes established optic flow, she felt less troubled by her thoughts. This became the basis for Eye Movement Desensitization and Reprocessing, or EMDR for short. In an EMDR therapy session, a patient moves their eyes back and forth, mimicking optic flow, while recalling a traumatic memory or fear-inducing situation. Coupling a low-stress state with the recall of a disturbing memory can “de-sensitize” the memory and help reduce its psychological impact. (5)

Even if you don’t have PTSD or an anxiety disorder, going for a walk can help you clear your head when you’re feeling particularly stressed or overwhelmed. Racing thoughts commonly come along with anxiety. If the cause of your stress or anxiety is a problem that can benefit from a calm and rational response, hitting the trail can be very helpful in reducing the pace of your thoughts, setting the stage for more effective solution-oriented thinking. These solutions will also likely be more creative than if you were mulling over that problem at home. A 2014 Stanford study established that walking produces a 60% increase in creative output, as compared to sitting. (6)

In addition to the links between walking and thinking that are presented here, a hiking trail offers the additional cognitive boosts that come with nature exposure. The next two articles will survey the restorative impacts of nature and discuss the science around nature-based exercise.

References

• G Leisman, AA Moustafa, & T Shafir. “Thinking, Walking, Talking: The Development of Integratory Brain Function.” Frontiers in Public Health. Apr 2016. 4(3).
• Jabr, Ferris. “Why Walking Helps Us Think.” The New Yorker. 3 Sept 2014. [https://bit.ly/3hYwgl7]
• N Zhao, Z Zhang, Y Wang, J Wang, B Li, T Zhu, & Y Xiang. “See your mental state from your walk: Recognizing anxiety and depression through Kinect-recorded gait data.” PLoS One. 22 May 2019. 14(5). [https://bit.ly/3AU9a80]
• “Change Your Brain: Neuroscientist Dr. Andrew Huberman.” Rich Roll (host) and Andrew Huberman (guest scientist). The Rich Roll Podcast. 20 July 2020 [https://www.richroll.com/podcast/andrew-huberman-533/]
• “History of EMDR.” EMDR Institute, Inc. [https://www.emdr.com/history-of-emdr/]
• Wong, May. “Stanford study finds walking improves creativity.” Stanford News. 24 April 2014. [https://news.stanford.edu/2014/04/24/walking-vs-sitting-042414/]