An experimental study found that exercising in the presence of nature — even virtual nature — provides psychological benefits over exercising without. The study, published in the International Journal of Psychophysiology, further identified areas of the brain that may be responsible for these effects.
Physical activity is a known stress reducer that may even be able to reduce a person’s mental health risk. Research suggests that exercising in natural environments, called “green exercise,” is particularly beneficial because it is experienced as more enjoyable, relaxing, and easier to follow compared to indoor exercise. Some evidence suggests that even the virtual presence of nature can produce these types of benefits.
Although these findings suggest something special about the way our brains process nature, the neural mechanisms are unclear. The authors of the new study aimed to better understand these underlying mechanisms by exploring what happens in the brain when people walk in nature.
“The reasons we are so interested in making exercise a more enjoyable experience are primarily due to the stress levels that most of us are currently experiencing,” said study author Marcelo Bigliassi, Professor associate professor of psychophysiology and neuroscience at Florida International University.
“We are aware of the benefits of green exercise, but the reality is that we don’t know much about what happens in the brain when we exercise in the presence of nature. Most of the psychological and perceptual responses reported in our study were expected to some degree, but we were also trying to unravel the brain mechanisms underlying these emotional states.
The study participants were 17 women and 13 men with an average age of 24 years. Subjects were randomly assigned to three different conditions in a counterbalanced order. During each condition, participants had to walk ¼ mile at their own pace.
In the green exercise condition, participants walked on a campus path surrounded by trees, greenery and natural sounds. In the virtual green exercise condition, participants walked indoors on a treadmill while watching and listening to a video of the campus trail route. In the control condition, participants walked indoors on a treadmill in front of a white wall.
Throughout the walks, brain activity was monitored via an electroencephalography (EEG) hood fitted to the participant’s head, and heart rate variability was monitored via a heart rate monitor attached to the chest. At the start, mid-point, and end of each walk, participants rated their attentional focus (internal to external), feeling (very bad to very good), and arousal (low to high).
For the most part, green exercise and virtual green exercise had significant effects on the study measures. However, the effects tend to be strongest for green exercise.
Compared to the control condition, the green exercise condition elicited more positive affect and greater emotional awareness. The green exercise condition, and to a lesser extent the virtual green exercise condition, also helped participants redirect their attention outward. This is notable because focusing on the present moment tends to be helpful in reducing anxiety symptoms. Both the green exercise and the virtual green exercise were found to be more enjoyable compared to the control condition.
Interestingly, in the green exercise condition, participants completed the walk faster compared to the other two conditions. This could be because participants were more focused on the present moment, and focusing on thoughts of the past and future was found to compromise movement execution. Additionally, being in nature leads to a sense of calm which can help improve automatic movement control.
In addition to the faster pace, green exercise caused higher physiological stress, as indicated by increased heart rate and heart rate variability. Notably, although physiological stress increased, participants in the green exercise condition experienced the most affective benefits. This suggests that the presence of nature may have counteracted the added stress of green exercise.
“The main takeaway from this study is that if you have a few minutes to spare in your day to relax, spending that time outdoors will maximize those results,” Bigliassi told PsyPost. “Your brain will react positively to this experience, although you may not be fully aware of it. Walking at light intensity for just 5 or 6 minutes in the presence of nature can really upregulate these low frequency waves. in the brain and improve the connectivity of several regions which will make you feel more relaxed.
The findings further shed light on the potential brain mechanisms responsible for these effects. The green exercise condition was associated with greater connectivity in the frontal and parietal regions of the brain. There was also an upregulation of low-frequency waves throughout the cerebral cortex, which the study authors say is associated with the “default mode network and a state of relaxation, in which individuals are more aware of their surroundings and emotional states.
The results suggest that exercising in the presence of nature provides greater psychological and physiological benefits than exercising without it. Moreover, virtual nature can produce some of these benefits, although to a lesser degree than real natural environments.
“We were really surprised at the size of the effect we saw with such a short intervention,” Bigliassi said. “Changes in electrical activity and functional brain connectivity were substantial, even though participants only spent about 5 minutes walking outside. This could have very serious implications for the mental well-being of people working in high-stress environments (meaning all of us?).
But the study, like all research, has some caveats.
“We are still trying to understand if we can achieve similar results with virtual reality, although this technology can only elicit partial environmental sensory stimulation (i.e. visual and auditory),” Bigliassi told PsyPost. “In addition, being away from your work environment, even for a few minutes, can induce a feeling of tranquility. We now have sufficient reason to believe that the effects of augmented reality and virtual reality will almost always be less pronounced than “real” interventions.
“I would like to thank my graduate student, Ms. Angeliki M. Mavrantza and my research collaborator, Dr. Giovanna Calogiuri for their assistance throughout the process,” added Bigliassi. “This was a very complex study in terms of data collection, signal processing and interpretation, which was only successful because we worked as a cohesive team from start to finish. “
The study, “Psychophysiological Mechanisms Underlying the Effects of Outdoor Green and Virtual Green Exercise During Self-Paced Walking,” was authored by Angeliki M. Mavrantza, Marcelo Bigliassi, and Giovanna Calogiuri.