As GoodGym grew, the organization expanded its reach, connecting runners with other volunteers in their neighborhoods and sending them to all sorts of projects in their communities. Every group run starts with a warm-up, where they learn more about that day’s mission. Then they run for a mile or two to the project location, maintaining a pace that lets them talk and share stories. A designated backmarker trails the pack to make sure no one gets left behind. GoodGym has also added walking groups, for those who need or prefer a slower pace. Once on site, they might sort donations, pull weeds, organize the neighborhood toy library, or, as one recent group did, cook spaghetti Bolognese and prepare beds for locals who are homeless. The day Wallace’s local group got soaked in the rain en route to the Goldsmiths Community Centre, the volunteers sanded down doors and frames to prepare them for fresh paint. Busy scrubbing wood with sandpaper, Wallace forgot her cold, damp clothes and soggy sneakers. When the rain let up, the runners distributed flyers around the neighborhood for the center’s upcoming Christmas Fair, where locals could enjoy mulled wine and mince pie and do some holiday shopping. After their return trek, the GoodGym volunteers cooled down with a stretch and made plans for their own Christmas get-together at a neighborhood pub.
Before GoodGym, Wallace ran for fitness only once every couple of months. Now she runs weekly with her group. “Every time I go to catch a train, I can see something I did,” Wallace says. One of her favorite group tasks was planting tulips, daffodils, and pansies in new flowerpots outside the neighborhood’s main shopping center. When she visited her grandmother soon after, her grandmother asked, “Did you see those giant plant pots at the Lewisham shopping center?” Wallace also has a coach in the neighborhood, a seventy-five-year-old man who lives alone. On her first visit, she was nervous, wondering, What if he doesn’t like me? What if we have nothing to talk about? She anticipated spending fifteen minutes, but ended up staying an hour, talking about life, books, martial arts movies, and the Blue Planet documentary series. “I didn’t think we’d have so much in common,” she told me. “One day I said to him, ‘I’m really happy we get on,’ and he said the same thing.”
Wallace is surprised by how strong her bonds have become with her local running group. She calls them her GoodGym family. When Wallace first heard about GoodGym, she was at a point in her life where she felt stuck in her daily routine. A single mom to a teenage daughter, she didn’t have many friends outside her coworkers, and she longed for a greater sense of community. On the one-year anniversary of her first run with GoodGym, she got emotional just thinking about how much her fellow runners had come to mean to her. “I know I could go to these people for anything,” she told me. “I’ve never really had that.” One of Wallace’s fellow Lewisham runners says that the original mission of the organization may have been to end social isolation in the elderly, but many of the volunteers feel just as isolated before they join. GoodGym has become a way to turn strangers who happen to live near one another into a tight-knit community.
Recently, GoodGym Hounslow runner Remy Maisel, who was recovering from strep throat, tweeted, “Tonight @goodgym came to MY rescue! I’m home sick, and was really sad to be missing my group run, until @GGHounslow came to me with my favourite treats to get through another day of bedrest. Thanks, guys.” The accompanying photo showed crispy mac ’n’ cheese bites, a white chocolate raspberry muffin, and a get-well card. Her tweet reminded me that sharing food is such a deep and primal part of how we know we belong to a tribe. Her tribe was making sure she was fed. How strange and lovely that the evolution of the runner’s high might have something to do with this part of human nature. How marvelous it is that by exercising or volunteering in packs, we can forge friendships that nourish us.
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REFLECTING ON THE RUNNER’S HIGH, ultra-distance runner Amit Sheth wrote, “Helen Keller said, ‘The best and the most beautiful things in the world cannot be seen or even touched. They must be felt with the heart.’ The experience of bliss while running is one of them.” When I read this, I thought he could just as easily have been describing the joy of belonging.
It’s a puzzling marriage, running and belonging. Why do our brains so readily link physical activity and social connection? And why does the biology of the runner’s high coincide so closely with the neurochemistry of cooperation? Whatever the reason, this is how we evolved. We are able to persist, for ourselves and for one another. Whether chasing down dinner, pushing a stroller up a hill, or running errands for a neighbor, we can take joy in the effort. And the more physically active you are, the more rewarding these experiences become. That’s because one of the ways that regular exercise changes your brain is by increasing the density of binding sites for endocannabinoids. Your brain becomes more sensitive to any pleasure that activates the endocannabinoid system; it can take in more joy. This includes the runner’s high, which helps explain why people find exercise more enjoyable the more they do it. But it also includes social pleasures, like sharing, cooperating, playing, and bonding. In this way, regular exercise may lower your threshold for feeling connected to others—allowing for more spontaneous feelings of closeness, companionship, and belonging, whether with family, friends, or strangers.
At first glance, the runner’s high seems an unlikely antidote to social isolation. And yet the neurobiological reward that kept our ancestors from starving may now save us from a more pressing hunger in modern society—loneliness. The link between physical activity and social connection offers a compelling reason to be active. It also serves as an important reminder that we humans need one another to thrive.
Chapter 2
GETTING HOOKED
In the late 1960s, Brooklyn-based psychiatrist Frederick Baekeland was trying to recruit exercisers for a sleep study. His last experiment had shown that exercise helps people sleep more soundly, and he wanted to test whether ceasing exercise would interfere with deep sleep. All he needed was to find regular exercisers who were willing to stop for thirty days. The problem was, nobody would sign up for the study.
Baekeland tried offering more money—significantly more than he had paid participants in the past. As he later wrote, “Many prospective subjects, especially those who exercised daily, asserted that they would not stop exercising for any amount of money.” Those who were eventually enticed to enroll complained not only of worse sleep but also of serious psychological distress induced by what they viewed as exercise deprivation.
This study, published in 1970, is widely considered the first scientific report of exercise dependence. Since then, numerous studies have shown that for regular exercisers, missing a single workout can lead to anxiety and irritability. Three days without exercise induces symptoms of depression, and one week of abstinence can produce severe mood disturbances and insomnia. Hungarian exercise scientist Attila Szabo declared longer experiments in exercise deprivation “hopeless.” Even if you could recruit participants, he argued, dedicated exercisers would, like addicts, cheat and lie about it.
Addiction is a popular analogy among both exercise enthusiasts and researchers. This analogy holds up in some ways. Physical activity can be mind-altering, affecting the same neurotransmitter systems as drugs like cannabis and cocaine. When exercisers claim to be junkies needing a fix, this high is surely part of what they’re chasing. Exercise enthusiasts also display certain quirks more commonly associated with chemical dependence. Just as alcoholics are easily distracted by the presence of wine or liquor, people who exercise regularly show an attentional bias toward anything related to working out. This phenomenon—known as attention capture—reveals a brain always looking for an opportunity to indulge a favored habit. Even more compelling parallels can be seen in neuroimaging studies. For example, when self-proclaimed exercise addicts view images of people working out, their brains’ craving circuitry fires up in a manner identical to what happens when you show cigarettes to a smoker. A small percentage of exercisers also sho
w symptoms of psychological dependence, agreeing with statements such as “Exercise is the most important thing in my life” and “Conflicts have arisen between me and my family and/or my partner about the amount of exercise I do.” One forty-six-year-old long-distance runner told researchers that she ran on a broken ankle for two years rather than take the rest needed to let the bones heal. Asked if anything could keep her from running, she said, “I suppose I could stop if somebody put shackles on me.”
These studies suggest that physical activity taps into the same capacity to get hooked as the most powerfully habit-forming substances. Considering the similarities between exercise and addiction can help us understand how physical activity changes the brain. It also helps explain why physical activity becomes more rewarding the more you do it. However, there are limits to the exercise-addiction analogy. Most exercise enthusiasts are not suffering from a dependence that interferes with their health or the rest of their lives. What they have, instead, is a relationship with exercise that involves desire, need, and commitment. When it comes to the passion people profess for their favorite physical activity, there may be better comparisons than substance abuse. The fact that people get hooked on exercise is not, in the end, a classic story of addiction. If exercise is a drug, the one it most closely resembles is an antidepressant. And for many of us—myself included—getting hooked on exercise points not to its inherently addictive nature, but to our brain’s capacity to latch onto a relationship that is good for us.
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For more than a decade, scientists have been trying to develop a pill that mimics the physiological benefits of exercise. Instead of working out, you would ingest a drug that produces many of the same molecular changes in your body as strenuous training. Not everyone is convinced this is a worthwhile pursuit; biologist Theodore Garland Jr. told a New Yorker journalist, “Personally, I’ve been more interested in the possibility of drugs that would make us more motivated to exercise.” Garland isn’t the only scientist to raise this idea. Exercise physiologist Samuele Marcora has proposed the use of psychoactive drugs to encourage people to be more active. The most promising candidates, he argues, would be caffeine, followed by modafinil, a tablet that keeps people with narcolepsy awake, and methylphenidate, an amphetamine-like stimulant. Notably, these three drugs act primarily on dopamine and noradrenaline, two neurotransmitters who levels naturally rise during physical activity and contribute to its mood-boosting effects. Marcora has even suggested that drugs that target the opioid system could be useful if they enhanced an exercise high. (“I still remember the first horrified reaction of an exercise psychologist when I told him about this idea,” Marcora writes.)
Whether this approach horrifies or intrigues you, it strikes me as overkill. It assumes that the human brain lacks the ability to find physical activity sufficiently rewarding and that it takes some other mind-altering substance to trick or tempt a person into liking exercise. But the research on this matter is clear: You don’t need a psychoactive drug to make exercise habit-forming. In many ways, exercise is the drug. Like highly addictive substances, regular exposure to exercise will over time teach the brain to like, want, and need it.
All addictions start in the brain’s reward system, and every drug of abuse—alcohol, cocaine, heroin, nicotine—acts on this system in a similar way. On first use, the drug triggers a flood of dopamine, the neurotransmitter that signals the presence of a reward. Dopamine grabs your attention and commands you to approach, consume, or do whatever set off the surge. Most drugs of abuse also increase other feel-good brain chemicals, like endorphins, serotonin, or noradrenaline. This powerful neurochemical combination is what makes a substance addicting.
Chronic use of such a drug eventually flips what researchers call the molecular switch for addiction. After repeated exposure to any habit-forming drug, a protein that helps the brain learn from experience accumulates inside neurons in the reward system. These proteins trigger long-lasting changes in dopaminergic brain cells that make them even more responsive to the substance that originally set off this process. In a regular cocaine user, the opportunity to use cocaine (and only cocaine) will trigger a tsunami of dopamine. For a heroin user, the possibility of taking heroin will set off a similar surge. In this way, consuming a drug teaches your brain to want it more.
Brains cells that have been sensitized in this way also become less responsive to other rewards; they have chosen their master. Try to tempt them with anything else and they will hold out. A cocaine-exposed reward system wants cocaine, not a home-cooked meal or a beautiful sunset. Once this molecular switch flips, all the signs of addiction set in. You will desire that reward over all others, become willing to sacrifice to obtain it, and suffer withdrawal if you cannot get it. This is the neurological path by which a short-lived pleasure (“This feels good!”) becomes a stable desire (“I want this!”) and eventually dependence (“I need this!”).
Scientists have observed these changes in brains that have learned, through regular indulgence, to crave cocaine, alcohol, and sugar. But what about exercise? The answer is complicated. In some—but not all—ways, physical activity clearly resembles a habit-forming drug. Exercise causes the brain to release many of the same neurochemicals as addictive substances, including dopamine, noradrenaline, endocannabinoids, and endorphins. With repeat exposure, running also flips the molecular switch of addiction. In laboratory studies with rats, running ten kilometers a day for one month had an effect on dopaminergic neurons similar to that of a daily dose of cocaine or morphine. Wheel-running rats also demonstrate behaviors similar to those of addicted humans; if they are blocked from their wheels for twenty-four hours, they go on running binges when access is restored.
There are, however, important differences between exercise and drugs like cocaine. One has to do with timing. Although you see similar changes in the brain’s reward system after exposure to exercise and drugs like cocaine, it takes longer to get hooked on exercise. Two weeks of wheel-running is insufficient to flip the molecular switch in laboratory rats, but after six weeks, rats run more each night and their brains show the neural signature of being hooked. Similarly, sedentary adults who begin high-intensity training show an increase in enjoyment over time, with pleasure peaking at six weeks. One study of new members at a gym found that the minimum “exposure” required to establish a new exercise habit was four sessions per week for six weeks. This delay in habit formation suggests that something different is happening, at a molecular level, than what occurs when a drug user becomes addicted. Drugs of abuse hijack the reward system and quickly take it over. Exercise seems instead to harness the reward system’s ability to learn from experience in a more gradual way. As one woman who had avoided physical activity all her life, then surprised herself by becoming a runner and cyclist in her forties, told me, “Things change slowly. Sometimes you don’t even recognize yourself as you’re changing. Now I’m most happy when I’m in sneakers.”
How you feel the first time you try a new form of exercise is not necessarily how you’ll feel after you gain more experience. For many, exercise is an acquired pleasure. The joys of an activity reveal themselves slowly as the body and brain adapt. One man, who his entire life had believed that he hated to exercise, told me that at age fifty-three, he decided to work with a personal trainer to improve his health and support his recovery in a twelve-step program. He started with one workout a week, and within three weeks, decided that he could tolerate a second weekly session. One day he left a training session and noticed that he was smiling, something he describes as shocking. “I realized that not only was I happy, I had found actual pleasure in my training session. I hadn’t believed that kind of pleasure was possible outside of addiction.”
For some people, it’s a matter of finding the right activity at the right time—such as the young single mother who felt isolated and “like nothing more than a mum” until she joined a recreational netball league
, found a network of friends, and discovered a new identity as an athlete. For others, it’s about finding the movement their bodies were made for. One woman who started rowing in her forties told me, “So many of the women I row with thought they weren’t athletes, but as soon as they got in the boat, their bodies said yes, and they found their home.” Humans are also more psychologically complex than laboratory animals running in wheels. We get rewarded not just by how exercise feels, but also by what the activity means. One woman started going to the gym after leaving an abusive marriage. After thirty-eight years of having her movements constrained by her husband, she found being out in public and walking on a treadmill incredibly liberating. As she puts it, “I know I’m in freedom when I move.”
Many people believe they don’t enjoy exercise in any form, but I’d bet that most of them aren’t immune to its rewards. It’s possible that they just haven’t exposed themselves to the dose, type, or community that would transform them into an “exercise person.” When the right dose, type, place, and time come together, even lifelong abstainers can get hooked. Nora Haefele of Stowe, Pennsylvania, didn’t start racing until her midfifties. Now sixty-two years old, she has completed more than two hundred events, including eighty-five half marathons. At her seventy-fifth half marathon, a race in Waterbury, Connecticut, the event director surprised her with a trophy, a golden sneaker with wings perched on a marble base with Haefele’s name inscribed on it. That trophy now sits on a table in her living room, close to the rack that holds her finisher medals.
The Joy of Movement Page 4
