Walking In Nature for Mental Health?

We hear so much about the weight control and fitness benefits of physical activity, but we forget about the benefits of physical activity on mental health, mood, stress, and cognition. At the same time, we have similar support of the benefits of being out in nature on mental health.

So, what if we were physically active in nature? 

Some recent research sought to answer this question, especially since the urban sprawl continues to consume space and opportunities for people to take a walk in nature. Also, could the reduction in natural environments and increase in mental disorders be correlated? Well, the authors cite research that suggests such a link, with decreased exposure to nature causing changes in psychological functioning.²

The first study randomly assigned 60 participant to walk for 50-minutes, either in a natural or urban environment around the university (see image below).³ They found that those who walked in nature experienced a reduction in anxiety, negative feeling states, and rumination (prolonged and often maladaptive attentional focus on the causes and consequences of negative emotions), alongside an increase in positive feeling states - as compared to the urban walking group.

The second study randomly assigned 38 participants to walk for 90-minutes in natural or urban environments, similar to their other study.⁴ Again, the nature walk significantly reduced rumination, while the urban walk did not.

They also measured brain activity (via bloodflow) before and after the walk. Specifically, they were looking at an area of the brain called the subgenual prefrontal cortex (sgPFC), which has been shown to be more active during sadness, rumination, and depression. 

In other words, we want this area of the brain to be LESS ACTIVE after a walk. Well, as you would imagine, the nature walk caused a significant decrease in activity in the sgPFC region, while the urban group's activity stayed the same. These changes in the brain might help explain the mental benefits experienced during the nature walk.

Urban Walking Not as Good?

Interestingly, the urban group did not produce the normal, known cognitive benefits of walking (even walks not in nature). Rather, the urban walkers did NOT get the expected reductions in anxiety, rumination and negative feelings. They also experienced a reduction of positive feelings!

So, what gives?

Well, the urban walk, with its noise, traffic, and hubbub might counteract the common stress and mood benefits of going for a walk. Of course, it would depend on if you perceive the urban walk as stressful or relaxing.

But, you can see the potential importance of having green, natural space within city limits that allows people to enjoy a relaxing nature walk, maybe taking a break from the stress and anxiety of work or life. 

Conclusion

Physical activity, including walking, provides numerous mood, stress, and cognitive benefits. Being in nature has also shown similar improvements, so new research is seeking to illustrate the the combined benefits of walking in nature. This research is timely as urbanization is consuming space and opportunities to take walks in nature.

Walking 50- to 90-minutes in nature improved positive feelings, while decreasing negative feelings, rumination, and anxiety. Walking nearby in a busy, urban setting did not see these same improvements, and actually resulted in NO improvements in anxiety and negative feelings. Thus, the urban setting might not allow for the normal mood and stress-reducing benefits of walking and physical activity - especially in those that perceive such an environment as stressful.

Try your own nature walk, and see what you think.

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References

1. Berto, R. (2014). The role of nature in coping with psycho-physiological stress: a literature review on restorativeness. Behavioral Sciences, 4(4), 394-409.
2. Bratman, G. N., Hamilton, J. P., & Daily, G. C. (2012). The impacts of nature experience on human cognitive function and mental health. Annals of the New York Academy of Sciences, 1249, 118–136.
3. Bratman, G. N., Daily, G. C., Levy, B. J., & Gross, J. J. (2015). The benefits of nature experience: Improved affect and cognition. Landscape and Urban Planning, 138, 41-50.
4. 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.
5. Hillman, C. H., Erickson, K. I., & Kramer, A. F. (2008). Be smart, exercise your heart: exercise effects on brain and cognition. Nature Reviews Neuroscience, 9(1), 58-65.