Thinking with Movement

This post is based on a new book by Annie Murphy Paul with some new ideas and data. The subtitle is The Power of Thinking Outside the Brain.

The author begins, “Dr. Jeff Fidler is a radiologist at the Mayo Clinic in Rochester, Minnesota. In the course of his professional duties, he regularly reviews fifteen thousand or more images a day that he used to do sitting down. Not anymore. These days Fidler walks as he looks, having set up a treadmill in front of the large screen that displays the radiological slides he is charged with examining. Within the first year of creating his ‘walking workstation,’ Fidler lost twenty-five pounds—and he felt convinced he was doing a better job of identifying the abnormalities hidden in the X-ray he scrutinized.

With a colleague, Fidler designed a study to test his hunch. Radiologists inspected a batch of images while seated, and while walking on a treadmill at one mile per hour. The participating physicians identified a total of 1,582 serious risks to the health of the patient. When they compared the ‘detection rates’ they achieved while sitting and while moving, the results were clear: radiologists who remained sitting spotted an average of 85% of the irregularities present in the images, while those who walked identified, on average, fully 99% of them.

A different set of research findings helps to explain the radiologists’ results. When we’re engaged in physical activity, our visual sense is sharpened, especially with regard to stimuli appearing in the periphery of our gaze. This shift, which is also found in non-human animals, makes evolutionary sense: the visual system becomes more sensitive when we are actively exploring our environment. When our bodies are at rest—that is, sitting still in a chair—this heightened acuity is dialed down.

Activity permissive settings are still the exception in schools and in workplaces, but we ought to make them the rule; we might even dispose with that apologetic-sounding name, since low-intensity physical clearly belongs in the places where we do our thinking. Meanwhile, medium-and high intensity activity each asserts its own distinct effect on cognition—as the psychologist Daniel Kahheman has discovered for himself.

Kahneman spends a few months each year in Berkeley, California, and on most days he takes a four-mile walk on a marked path in the hills, with a clear view of San Francisco Bay. Ever the scientist, Kahneman has subjected the experience to close analysis. ‘I usually keep track of my time and have learned a fair amount about effort from doing so,’ he writes. ‘I have found a speed, about 17 minutes for a mile, which I experience as a stroll. I certainly exert physical effort and burn more calories at that speed than if I sat in a recliner, but I experience no strain, no conflict, and no need to push myself. I am also able to think and work while walking at that rate. Indeed, I suspect the the mild physical arousal of the work may spill over into greater mental alertness.’

He noted, however, that ‘accelerating beyond my strolling speed completely changes the experience of walking, because the transition to a faster walk brings about a sharp deterioration in my ability to think coherently. As I speed up, my attention is drawn with increasing frequency to the experience of walking and to the maintenance of the faster pace. My ability to bring a train of thought to a conclusion is impaired accordingly. At the highest speed I can sustain on the hills, about 14 minutes, I do not try to think of anything else.’

Kahneman’s careful self-observations are backed up by empirical research. Moderate-intensity exercise practiced for a moderate length of time, improves our ability to think both during and immediately after the activity. The positive changes documented by scientists include an increase in the capacity to focus attention and resist distraction; greater verbal fluency and cognitive flexibility; enhanced problem-solving and decision-making abilities; and increased working memory, as well as more durable long-term memory for what is learned. The proposed mechanisms by which these changes occur include heightened arousal, increased blood flow to the brain, and the release of a number of neurochemicals which increase the efficiency of information transmission in the brain and which promote the growth of neurons, or brain cells. The beneficial mental effects of moderately intense activity have been shown to last for as long as two hours after exercise ends.

The encouraging implication of this research is that we have it within our power to induce ourselves a state that is ideal for learning, creating, and engaging in other kinds of complex cognition: by exercising briskly just before we do so. As things stand, however we don’t often take intentional advantage of this opportunity. Our culture conditions us to see mind and body as separate—and so we separate, in turn, our periods of thinking and our bouts of exercise. Consider how many of us make our visits to the gym only after work, for example, or on weekends. Instead, we should be figuring out how to incorporate bursts of physical activity into the work day and the school day—which means rethinking how we approach our breaks. Lunch breaks, coffee breaks, downtime between tasks or meetings: all become occasions to use exercise to maneuver our brains into an optimally functioning rate.”