Take, for instance, proprioception, to begin simply. It’s a concept well within anyone’s grasp, quite literally, and it’s a good way to begin. Imagine yourself forced to navigate a dark room crowded with the usual obstacles, like furniture, tight turns, and a light switch across the room. First, you reach out and use proprioception to know where your hand is without seeing it, but you also use your sense of touch to gather information that feeds your brain, taps memories, and reconstructs a map of the room in order to steer your body toward the switch. Part of what is going on here is proprioception, the brain’s ability to use signals from your hand to tell you where you are in space and where you should go. Proprioception is your brain’s ability to know where your body parts are relative to one another at any given moment.
Also at work are the extraordinary abilities of the hands to gather information, the sense of touch and perception through touch that we rely on in activities like writing with a pencil, manipulating tools, playing the guitar, and foreplay. All of this feeds the brain in a sort of map, and not just of the hand. The surface of the brain contains almost literally a map of various points on our body, a diagram that the brain uses to build the sense of where we are in space. This map even speaks to priorities: our hands, our most important instruments for command of the sensory world, map out on the brain right next to our genitals, areas of maximum sensitivity staked out by evolution for good reason, and so the example of foreplay above is not nearly as frivolous as it might have seemed at first. Likewise, our feet are mapped next to our hands, signaling their importance in guiding us through space, in coordinating with the brain to maintain our sense of order, direction, and balance. The extraordinary sensitivity of our hands to guide us through a dark room ought to be equaled by the ability of our feet to guide us through the world—but, as with many of our evolutionary endowments, civilization has short-circuited the relationship, in this case with shoes. While it may not have been the intent, all that foam and gadgetry and those stiff soles robbed the feet of proprioception, and robbed our brains, our neural circuitry, of the refined information and information processing that directed us for millions of years.
With aging, we worry about matters such as cancer and heart disease or maybe even Alzheimer’s taking us out or leaving us debilitated in a nursing home, but gerontologists say that a far more prosaic problem is a bigger one. The simple act of falling often breaks hips and legs and robs people of independence and mobility prematurely. We fall because we have lost our sense of balance, literally lost our way in the world, or, more to the point, have given it up by allowing the neural circuitry that oriented us to atrophy.
This is not to argue that we will solve all our problems simply by getting rid of shoes, or by wearing minimalist shoes. Rather, we offer this as simply one more case study in unintentional damage done by insulating ourselves from the real world. But this is just the beginning. We didn’t tell you this, but we had you in minimalist shoes along that mountain trail, so at every twist and turn, your feet were playing a symphony of muscles and nerves to roll off rocks, bank off curves, accelerate, and brake. But this was about far more than feet. Each time you shifted gears from uphill to down or from straight to curve or to hop a rock, a new set of muscles came into play, or the same set of muscles shifted from push to pull, from expand to contract. Quads, calves, and hamstrings, sure enough, but also hips if your stride was right and the full girdle of muscles that wrap your abdomen—all engaged in not just the running but the breathing, the twisting and turning. And you didn’t just run. On the uphills you pushed your heart well beyond its aerobic rate, held this as long as you could, then you walked, and suddenly a whole new set of muscles came on line.
Simply by engaging the real, rocky, rolling world and its variety of stresses and varied challenges, you have engaged the full range of muscular and neurological activity that evolved in places just like this. And more than muscles and neurons. Take, for instance, that little giggle you had after that long uphill slog, the summit experience, that little triumph over adversity and challenge. What lay behind that rush of elation was a squirt of biochemistry stimulated by the muscle activity but crucial to your sense of well-being and your brain. Doubtless dopamine was a part of this little reward, the rush that we try to replace with drugs and stimulants or try to re-create with prescription antidepressants. Here it is free for the taking. But here we can see the evolutionary logic behind it: these little rewards are evolution’s way of keeping us going, of making us survive. Evolution has made provisions for our happiness, but to take advantage of them you’ve got to move.
DISCOVERING A NEW WAY TO MOVE
Matt O’Toole has always made his living on health and fitness, enjoying a twenty-five-year career that has, when we talked to him, taken him to the head of the international sports gear manufacturer Reebok. He is buff and tough, as you might expect, and he dresses in the athletic casual code common in the Reebok offices just outside Boston. Like Reebok itself, O’Toole has recently undergone something of a personal transformation.
“I had started a streak about nine years before [my transformation]. I was running every day and I decided to make that my form of exercise, because I was always finding that when I had a different routine I could easily break it. I would miss two or three days because of traveling. So I started this thing where I ran every day, so if I got a streak going, I would not break it. But what happened at the end of nine years, my body was actually a wreck. I had all kinds of back problems, knee problems. My back problem got so severe that my doctor told me I couldn’t run anymore.” It was an odd admission for a guy in the business of selling running shoes.
Running was probably not O’Toole’s problem as much as was the fact that he did it every day and did it in that flat, monotonous pattern of a street runner, a treadmill runner—but that’s not our point here. The point is where O’Toole and Reebok went. He joined CrossFit, a worldwide formalized form of exercise that stresses a variety of movements: weight training, jumping, running, throwing, push-ups, pull-ups—all designed to involve the entire body, recruit all muscles, just as it recruits heart, lungs, and mind. Further, it is done in groups of people and is competitive, but not in the sense of team against team. Rather, there is a group ethic. You compete against yourself first and the group cheers you along, marks progress, forms a sort of community. We’ll have lots more to say about the element of community in a later chapter, but for the moment, let’s be reductionist and stick with the physical.
O’Toole’s back problems simply went away with CrossFit. His new routine was so transforming that it has transformed Reebok itself. The corporation has consciously and explicitly moved away from the model that tied sales and promotion to professional athletic superstars in football, soccer, hockey, and basketball (sports in which most participation involves a couch and a flat-screen television). Instead, Reebok has specifically endorsed CrossFit and is basing its corporate direction on getting people off couches and into gyms.
But there needs to be a bit of disclosure here, especially because one of the authors’ direct involvement with Reebok is part of this story. John is a paid consultant to Reebok, hired to help shape this transition and to guide a comprehensive program of exercise based in schools. O’Toole says that reading John’s book Spark was every bit as important as CrossFit in shaping a new direction for Reebok.
Again, we’re not offering CrossFit here as a prescription so much as it is an illustration. We hope you hear in our brief description of CrossFit an echo of our earlier conversation with David Carrier, the University of Utah biologist who has spent a career looking at topics like persistence hunting and movement. Remember, Carrier’s ultimate point was that the human body is unique among the bodies of our close relatives, our fellow mammals, in not having a sweet spot, in having muscles and a supporting skeletal system designed for a whole variety of movements. We are, as we’ve said, the Swiss Army knives of movement, and CrossFit is one exercise program consciously designed
to reflect that fact. There are others, specifically some forms of martial arts and even dance that are evolving to grasp this awareness of the human body. Our prescription does not necessarily lock you into a gym. It certainly doesn’t lock you on a treadmill in front of a flat-screen.
In our conversation with O’Toole, another echo emerged in his description. Repeatedly, he cited the variety of activities as being among CrossFit’s greatest attraction. This word “variety,” if you recall, was also pivotal in our earlier discussions of food and nutrition, pivotal in our consideration of human evolution. A standout feature of humanity in evolutionary terms was the ability to adapt and thrive in a variety of environments facing a wide variety of challenges. Evolution tells us that this overarching condition of our deep ancestral past is also the foundation of our present well-being and happiness.
And, in fact, this idea can steer us toward a metric of sorts. Yes, we have shied away from a specific prescription in our arguments, preferring to lay out some general ideas like variety to guide you toward a personal program. We are not saying you must go to a gym and do so many reps of these and a half hour of those at this heart rate at that frequency wearing this brand of shoe and fueling on this sports drink and supplement. All well and good, but how do you know you’re on the right track? Weight loss? Tighter abs and butt? Posture? IQ test? None of these. We’ve got a better one, and, in fact, O’Toole brought it up on his own, unprompted, during our conversation.
“With CrossFit I realized right away the reason I wanted to keep coming back was it was a lot of fun to be around these people and do things that I hadn’t been doing and really challenge myself,” he said. “The experience became a lot more positive, where with running it was, check the box, I have to do it. CrossFit was, hey, I might actually want to do this.”
That’s it. That you actually begin to look forward to that point in the day when you get to cut loose and move, that you want to do this. That’s when you know you are on the right track, and don’t give up until you are. We’re telling you that whatever form of movement you do to stay healthy is not right until it gets to be fun. Enjoyable. Nor is this as squishy and nebulous as it might seem. Remember the pathways of biochemistry between muscles and brain. Much of that chemistry is wound up in building a better brain, but much of it is also wound up in rewards, in feeling better, in being attuned to your body’s signals that tell you that you are okay, on the right path, and moving forward.
And then one thing leads to another; for O’Toole, it leads to a mountaintop. Although he described himself as “not an outdoor person,” he nonetheless decided to mark his fiftieth birthday and the changes in his life by climbing Africa’s Mount Kilimanjaro.
DEEPER LAYERS
Our description of the mountain run was, we argued, information-rich, but now is where we admit to rigging the argument a bit more than you may have noticed. As we said, the information contained in the actual run was at least several orders of magnitude greater than would fit on a page, a flood of data to the runner’s brain. Nonetheless, there were a couple of simple facts embedded in our description that freighted far more meaning than you probably realized. Remember the dog? Remember how the dog almost knocked you off a cliff at a critical juncture and that this apparent conflict resolved itself by a quick movement instinctive to both dog and runner? In this nanosecond, the runner’s brain was presented with a whole set of information way outside the box of the usual exercise routine; at bottom, there was a calculation and evaluation of the well-being of something outside himself, an animal he cared about and even loved. He first faced a moment of peril and then shared that peril with another being in a burst of empathy. Do I kick the dog off the edge of this cliff, or do I go off myself? Then a decision, and then survival. How important was this moment in enriching the experience? This question deserves examination in detail, and we will do just that in a subsequent chapter about empathy and caring and our brains. But first, we need to point out a few more elements of this run that foreshadow larger considerations. It was a mountain run, an experience in the real world. It included ice, rock, mountains, wind, sun, and sweeping vistas of grassy slopes and valleys. It was grounded in nature, which is our ancestral home, the context of human evolution. How much of the value the runner gained from this experience derived from that context? This question deserves its own chapter and will get one.
But this context raises another idea, and we will turn to this idea next. Nature is a valuable setting for our challenges because it just doesn’t care about us and is all-powerful. The day that we described was relatively benign. There was sun and blue sky to soften the edges of ice and rock, but every mountain runner and trail runner knows that it could just as easily have been otherwise (and often is), that winds at ridges can summon blasts strong enough to knock you off your feet, or a weather front can blow in whiteout blizzards and temperatures plunging to subzero in a matter of minutes. What do you do about your run on such days? Do you gear up in the latest wonder fabric and press on? Some days, sure you do. There is value in facing a challenge that is real and has real consequences.
But think about our ancestors who faced such conditions routinely and without benefit of wonder fabric. Sometimes the right thing to do is press on, and sometimes it’s better to hunker down, to retreat downslope to the cave and the fire and a circle of family, friends, children, and dogs curled in the corner in tight, heat-holding balls. And then it is time to sleep. You’ve got to move, and then you’ve got to rest.
5
Bodies at Rest
Why Sleep Makes Us Better
The writer Elizabeth Marshall Thomas may have the most privileged window into the wild life. As a child in the early 1950s, she accompanied her eccentric, wealthy parents on an expedition into a then-unexplored and unroaded region of southwestern Africa, the Kalahari, in what was among the first contacts by civilized people with the hunter-gatherers she calls Ju/wasi, otherwise known as the !Kung or San. These are the guys in the photo we showed you in our introduction. She lived among them for long periods and in a 2006 book, The Old Way, recorded her memories in exquisite detail, some of it greatly illustrative of the case we make, some of it enigmatic, puzzling, and even contradictory, as any account of the human condition must be. But at the moment, we focus on this recollection because of what it tells of the subject we now turn to: sleep.
A further safety measure is that everyone sleeps lightly and not at the same time. In the Ju/wa camp at night, someone always seemed to be awake, getting warm by a fire or having a sip of water from an ostrich eggshell.… The arrangement was very informal, not like a soldier’s guard duty or a sailor’s watch. It just seemed to happen, part of the normal way of life.
Normal for them, maybe: they were guarding against lions. But what has this to do with us? Ultimately, this account steers us to the context of the wild life, and how the wild taught us how to sleep.
Probably the best place, though, to begin asking about sleep is in the noontime basement cafeteria of Boston’s Beth Israel Deaconess Medical Center. Lions are not an obvious presence in the lunchtime rumble and chatter of a research hospital cafeteria, crowded with mostly scrubs-clad medical stars and up-and-coming stars, as harried, caffeinated, and sleep-deprived as the rest of us. No one knows more about this than our host at this lunch, Robert Stickgold, one of the world’s leading researchers on sleep, who works out of a lab based at Beth Israel. Mostly people call him Bob, which fits his informality and directness. He is the sort of scientist who knows the data, and knows what the data can and can’t tell us, and what it can’t tell us is the answer to the most fundamental question: Why do we sleep?
“We understood the biological functions of the sex drive, hunger, and thirst two thousand years ago, and for sleep we didn’t know it a dozen years ago, so the first thing I would suggest is, it is subtle,” he says. Nonetheless: “If you don’t sleep, you die. The rat work is very clear, but after twenty years [of studying this], we don’t know why the rat
s die. Cause of death unknown.”
That’s not the same as saying we don’t know what will go wrong if we don’t sleep, just that it’s not at all clear what it is about this state of apparent mental and physical retreat, this little death each of us must go through each day that serves our well-being. And what can go wrong for the sleep-deprived—we’ll bet most of us are—ought to be front and center in the broader conversation. Here’s a snippet from our conversation.
Stickgold: If you don’t get enough sleep, you are going to end up fat, sick, and stupid.
Ratey: Which is the way the world is going anyway.
Stickgold: And that may be why.
Fat: Stickgold says the Iraq War, which consumed multitrillions of dollars across the decade of American involvement, really ran on Snickers bars. As wars go, Iraq was a standout for a variety of reasons, but mostly it was an air war and mostly it was fought at night when American technology granted complete command of the dark. As a result, a lot of sleep was lost, which has prompted a great deal of research, especially by the military. Now we understand that one of the consequences of sleep deprivation is craving the very dense carbohydrates and sugars that featured so prominently in our discussion of nutrition. Researchers have since duplicated the phenomenon with studies that deprived volunteers of sleep.
Go Wild Page 11