Easing Brain Fatigue With a Walk in the Park

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 brain fatigue simply by strolling through a leafy park.

The idea that visiting green spaces like 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. Instead, 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 and reduce mental fatigue.

But this 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 brought volunteers into a lab, attached electrodes to their heads and shown them photographs of natural or urban scenes, and found that the brain wave readouts show that the volunteers are more calm and 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. Or it wasn’t, until the recent development of a lightweight, portable version of the electroencephalogram, a technology that studies brain wave patterns.

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

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

The first half mile or so took walkers through an older, historic shopping district, with fine, old buildings and plenty of pedestrians on the sidewalk, but only light vehicle traffic.

The walkers then moved onto a path that led through a park-like setting for another half mile.

Finally, they ended their walk strolling through a busy, commercial district, with heavy automobile traffic and concrete buildings.

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

Throughout that time, the portable EEGs on their heads continued to feed information about brain wave patterns to the laptops they carried.

Afterward, the researchers compared the read-outs, looking for wave patterns that 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 the urbanized, busy areas, particularly the heavily trafficked commercial district at the end of their walk, their brain wave patterns consistently showed that they were more aroused, attentive and frustrated than when they walked through 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 professor in the School of the Built Environment at Heriot-Watt University, 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.

But even so, she said, the findings were consistent and strong and, from the viewpoint of those of us over-engaged in attention-hogging urban lives, valuable. The study suggests that, right about now, you should consider “taking a break from work,” Dr. 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, Dr. Roe helpfully assured us. “It is likely to have a restorative effect and help with attention fatigue and stress recovery.”

-by Gretchen Reynolds, The New York Times

Don't stress about it, mon

This is just a powerpoint slide I plucked from a previous lecture - credit for the pic goes to Dr M.C.Pardon of the Uni. of Nottingham Medical School (QMC), who does research on stress & neurodegenerative disease.

Adaptive responses to stress are generally more short term and they are usually quite good for you. As a result, one can conclude that some stress is actually good for you. However, too much stress leads to pathological responses which are bad.

Stress responses of the body are mediated by the hypothalamus. The hypothalamus releases a hormone called CRH (corticotropin releasing hormone) into the median eminence, which transports the hormone via the blood to the anterior pituitary. Cells of the anterior pituitary then release ACTH (adrenocorticotrophin releasing hormone) into the blood supply which circulates to the Adrenal glands (which sit on your kidneys like little hats). The adrenals are responsible for releasing all kinds of steroid hormones, but in this context, it’s cortisol they’re releasing. If you want to be all savvy and smart about it, then you cansay that the stress hormone, cortisol, is released by the Zona Fasiculata of the Adrenal Cortex in response to ACTH. Cortisol is a derivative of cholesterol. All steroid hormones are derivatives of cholesterol, for that matter. Examples of steroid hormones are Oestrogens, Testosterone, Progesterone and Aldosterone. As we can see from that non-exhaustive list, cholesterol has a pretty important role to play in your sexuality, sex life, and reproduction.

Examples of Steroid hormones.

Cortisol is the hormone which causes the majority of the bodily changes associated with stress. Most of the effects described in that first picture are the results of cortisol. Stress, through the action of cortisol, leads to the breakdown of energy reserves. This is why prolonged stress leads to weight loss. Evolutionarily, this would have been advantageous as a typical stress response would have been something along the lines of a sabre-toothed cat or lion raiding the camp, and mobilising energy stores would have got you all alert and ready to take on the threat. To continue along this vein, stress downregulates the action of the amygdala (the fear centre), which gives a reason why you might be a little more fearless under stressful situations (such as lion attack). Stress also downregulates the Supraoptic Nucleus of the hypothalamus. This region of the hypothalamus is responsible for releasing Oxytocin. Oxytocin is an important neurohormone involved in social bonding and love. The decreased oxytocin release indicates as to why stressed out people tend to be less sensitive about other people, and more prone to lashing out.

Spongebob Stressedpants.

We must remember that stress doesn’t only arise from life threatening situations such as a lion attack or a Justin Bieber concert. Stress responses arise from many daily activities, and the body is aware of this. When you are sleeping, you are under less stress (or unaware of any stressful situations), so your cortisol levels are very low. But prior to waking (which is determined by your body clock and sleeping routine), your cortisol levels rise by a large amount (around 50%, if you’re interested). This is known as a rheostatic mechanism. The body is changing in anticipation of an event. The body is anticipating the stress of daily life, so is releasing cortisol in advance. The body can then adjust to the daily stresses as they come.

So we can see from the initial diagram that too much stress can lead to heart disease, impotence and possibly diabetes (through the insulin resistance). Cortisol also downregulates the immune system, by decreasing the mobility of white blood cells and stimulating less antibody release. It kind of explains why more people get ill at around exam time. Another reason for excessive illness around exam time is that students are getting less sleep (from all that hard studying, of course!), and sleep is important for giving the immune system a kick. Sleep states release melatonin (the sleep hormone), and melatonin upregulates the immune system.

Melatonin and the immune response. Diagram from ‘Melatonin - a pleiotropic molecule involved in pathophysiological processes following organ transplantation’, J. E. Fildes et al, Immunology.

And to cap off this post, some research done by a Professor of Neurology at the University of Minnesota, called Adnan Qureshi (he totally robbed my surname), indicates the cat owners are less likely to suffer from heart attacks. The reason for this is unclear but a couple of theories are that cat owners have personality traits which may protect them from heart attacks, or it may well be the soothing, stress relieving feeling of stroking and looking after the cat that reduces cortisol levels. I’m not sure, and neither is Prof. Qureshi (that name stealing fiend) - but as a cat lover, this news pleases me.