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Walk This Way: Steps to a Better Brain
Movement Improves Your Smarts, Mood, More. Reviewing Caroline Williams’s ‘Move!’
After retrieving my copy of Bloomberg Businessweek from the mailbox, the first article to catch my eye concerned commuting to work—something I mostly avoid these days. I work a mile from my house. I walk it as often as time and weather permit, and when I drive it takes two minutes. But I’m an outlier; others have farther to go. A research team at Dartmouth equipped information workers with fitness trackers and monitored them for a full year. They found time in the car before work negatively affected performance on the job the rest of the day.
Researchers said routinizing the commute—following the same schedule, same route, and so on—mitigated the downsides. Same with walking or biking. “The researchers found that commutes involving more physical activity, such as walking or bicycling, correlated with less stress and better performance at work,” said Arianne Cohen, who penned the story. But I suspect there’s more going here than a simple tradeoff of less stress on foot than behind the wheel.
There’s good reason to believe, according to science writer Caroline Williams’s book, Move! The New Science of Body over Mind, that walking has positive effects on everything from emotional well being to cognition. What’s more, these effects outstrip any gains from mere stress reduction.
‘Cognitively Engaged Endurance Athletes’
At the risk of oversimplification, physical activity—like commuting to work on foot or hitting the gym beforehand—improves mental function. The effect is bound to show up at work, or anywhere else for that matter. “Our biological baseline is to be on our feet, moving and thinking at the same time. If we don’t do it, our brains make the sensible decision to save energy by cutting brain capacity,” says Williams. “In better news, when we get on our feet and move, it primes the brain to be alert and to learn.”
This priming happens at the neurological level. Movement triggers the release of brain-derived neurotrophic factor, BDNF, a molecule that boosts memory and neural connectivity. Psychiatrist John Ratey famously called it Miracle-Gro for the brain. To assist the process, the body actually sends more blood to the brain. “Any form of aerobic exercise will increase blood flow to the brain by around 20–25 percent, at least in the short term,” says Williams. Gravity optimizes the effect. Putting your full weight on your feet actually increases blood flow to the brain an additional 10–15 percent.
Another factor at play is a molecule called osteocalcin, which is produced by the bones. As bone tissues regenerate during and after exercise, they release osteocalcin which then crosses the blood-brain barrier and has noticeable effect on memory function. Williams notes the research here is in its early stages, but the evidence so far suggests staying on our feet helps preserve our memories as we age.
How much should we walk? I listened to Move on audiobook as I—what else?—walked. I am a pretty serious walker; I average about seven miles a day, 16,000 steps or so. We’re all familiar with the 10,000-step target; it was cooked up as part of a marketing gimmick, but it was remarkably accurate. Assuming the lifestyles of primitive peoples indicate something of an evolutionary baseline, Tanzania’s Hadza tribe presents an interesting case study. The Hadza, modern-day hunter-gatherers, are on their feet quite a lot. Hadza men log between 8,000 and 15,000 steps a day. Humans are, as Williams quotes a USC professor saying, “Cognitively engaged endurance athletes.”
Stand, Stretch, Dance, Breathe
Walking also activates our core muscles, which turn out to matter far more than I’d ever imagined. The core is—pardon me—core. Good posture is correlated with good mood and reduced stress, anxiety, and fatigue. Activating your core lowers mental and emotional stress. And a good belly laugh works as well as sit-ups; maybe that’s one of comedy’s secret mechanisms on our moods.
Williams covers several other aspects of movement and its effect on the brain. Stretching? Yes, do it. Dance? Rhythm is the killer app. Strength training? The whole brain vs. brawn dichotomy is bogus. In fact, Williams points out,
Evidence from psychology studies has been accumulating for some time that having the physical skills to get out of sticky situations makes a big difference to how mentally capable and emotionally resilient we feel as we battle our way through life.
And the psychological studies find support in the observable features of the brain itself. Says Williams,
There is also a link between bodily strength and a healthy brain. A ten-year study of twins showed that greater strength in middle age is linked not only to more grey matter but also to a better functioning memory and a quicker brain a decade later, while grip strength (an overall indicator of muscle power) is associated with a healthier hippocampus [a key brain structure for memory].
The problem is that we’re getting weaker. A recent study compared the grip strength of modern men to twenty- to thirty-five-year-old students in 1985. “The men of the 1980s could exert 117 lb. of force,” says Williams, “compared to millennial man’s measly 98 lb.”
One muscle easy to overlook while we talk about strength is the diaphragm. Williams spends an entire chapter on breathing. As humans, we use breathing to regulate mood. We not only involuntarily sigh every now and then to increase oxygen in our bloodstream, but we can manipulate our breathing to produce particular effects. Breathing help us regulate mood because it’s correlated with brain states. Particular brain waves move at particular speeds, and oxygenating our blood in keeping with ideal speeds can elevate our mental state.
Williams recommends six breaths per minute as a perfect way to foster a more relaxed mindset. “Breathing in and out over the space of ten seconds hits a physiological sweet spot that connects the breathing-related movements of the body to blood flow, blood pressure and the concentration of oxygen in the blood,” she says. “Plus, it tips the balance of the autonomic nervous system from ‘rev up’ to ‘calm down.’” She calls this strategy “a short-cut to a sense of calm and contentment.” And it turns out you can do this pretty easily while walking. It’s basically five steps while inhaling and five steps while exhaling.
Incidentally, for anyone interested in Christian mysticism this might shed some light on the traditional practice of reciting the Jesus Prayer while breathing slowly. “The breathing is to be made slower and at the same time co-ordinated with the rhythm of the Prayer,” explains Metropolitan Kallistos Ware. “Often the first part, ‘Lord Jesus Christ, Son of God’, is said while drawing in the breath, and the second part, ‘have mercy on me a sinner’, while breathing out.” That pattern pretty much amounts to six-breaths per minute, at least when I do it. I sometimes do so walking.
Praying or not, the point here is movement. Williams offers a manifesto and several helpful tips on incorporating more movement into the day, including how to rest for better refreshment and mental revitalization. There’s far more than stress or even physical health to factor when we think about movement. Improved mental performance is a few pushups, a jog, or stroll away.
By the way, if you want to go deeper on the topic of movement, here are some additional suggestions:
Daniel Lieberman, Exercised: Why Something We Never Evolved to Do Is Healthy and Rewarding
Bill Hayes, Sweat: The History of Exercise
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