Easing brain fatigue? It’s a walk in the park

Gretchen Reynolds / New York Times News Service /

Published Apr 9, 2013 at 05:00AM

Scientists have known for some time that the human brain’s ability to stay calm and focused is limited and can be overwhelmed by the constant noise and hectic, jangling demands of city living, sometimes resulting in a condition informally known as brain fatigue.

With brain fatigue, you are easily distracted, forgetful and mentally flighty — or, in other words, me. But an innovative new study from Scotland suggests that you can ease it simply by strolling through a leafy park.

The idea that visiting parks or tree-filled plazas lessens stress and improves concentration is not new. Researchers have long theorized that green spaces are calming, requiring less of our so-called directed mental attention than busy, urban streets do. Natural settings invoke “soft fascination,” a beguiling term for quiet contemplation, during which directed attention is barely called upon and the brain can reset those overstretched resources.

The theory, while agreeable, has been difficult to put to the test. Previous studies have found that people who live near trees and parks have lower levels of cortisol, a stress hormone, in their saliva than those who live primarily amid concrete, and that children with attention deficits tend to concentrate and perform better on cognitive tests after walking through parks or arboretums. More directly, scientists have put volunteers into a lab, attached electrodes to their heads, shown them photos of natural or urban scenes, and found that the brain wave readouts show that the volunteers are calmer and more meditative when they view the natural scenes.

But it had not been possible to study the brains of people while they were actually outside, moving through the city and the parks. At least not until the recent development of a lightweight, portable version of the electroencephalogram, a technology that studies brain wave patterns.

For the new study, published last month in The British Journal of Sports Medicine, researchers at Heriot-Watt University in Edinburgh and the University of Edinburgh attached the portable EEGs to the scalps of 12 healthy young adults. The electrodes, hidden beneath a fabric cap, sent brain wave readings wirelessly to a laptop carried in a backpack by each volunteer.

The researchers, who had studied the cognitive impact of green spaces for some time, sent each volunteer out on a walk of about a mile and half that wound through three different sections of Edinburgh.

The first half-mile took them through a historic shopping district with fine, old buildings and plenty of pedestrians, but only light vehicle traffic. They then took a path that led through a parklike setting for another half-mile. Finally, they strolled through a busy, commercial district, with heavy traffic and concrete buildings.

The walkers had been told to move at their own speed, not to rush or dawdle. Most finished in about 25 minutes.

During that time, the portable EEGs continued to feed information about brain wave patterns to the laptops they carried.

Afterward, the researchers compared the readouts, looking for wave patterns they felt were related to measures of frustration, directed attention (which they called “engagement”), mental arousal and meditativeness or calm.

What they found confirmed the idea that green spaces lessen brain fatigue.

When the volunteers made their way through busy, urbanized areas, particularly the heavily trafficked district at the end of the walk, their brain wave patterns consistently showed they were more aroused and frustrated than when they walked in the parkland, where brain-wave readings became more meditative.

While traveling through the park, the walkers were mentally quieter.

Which is not to say that they weren’t paying attention, said Jenny Roe, a lecturer at Herriot-Watt’s School of the Built Environment, who oversaw the study. “Natural environments still engage” the brain, she said, but the attention demanded “is effortless. It’s called involuntary attention in psychology. It holds our attention while at the same time allowing scope for reflection” and providing a palliative to the nonstop attentional demands of typical, city streets.

Of course, her study was small, more of a pilot study of the nifty new, portable EEG technology than a definitive examination of the cognitive effects of seeing green.

Even so, she said, the findings were consistent, strong and, for attention-hogging urban lives, valuable. They suggest that, right about now, you should consider “taking a break from work,” Roe said, and “going for a walk in a green space or just sitting, or even viewing green spaces from your office window.”

This is not unproductive lollygagging, Roe assured: “It is likely to have a restorative effect and help with attention fatigue and stress recovery.”

Lowering your stress by visiting a green space is not a new idea, but until the development of a lightweight, portable electroencephalogram the idea couldn’t be put to the test. Now it has — with an innovative study from Scotland.

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