Sometimes when she’s running, Bender finds herself reflecting on her journey. “It’s usually at the end of a long run. I start thinking about where I was and where I came from,” she says. “Sometimes I cry when I run. I assume no one’s noticing because I’m super sweaty. I’m never really sure if it’s a runner’s high or I just can’t believe I’m able to do this. I’m so proud of myself. There was a time I couldn’t, and it wasn’t that long ago.” The park Bender runs in has a dirt path through the woods and a creek that is difficult to cross. The terrain is irregular, with rocks that are easy to stumble on and the occasional snake to avoid. “At some point along my run, I stop looking at the ground in front of me. I stop looking for uneven trail, acorns on the path, or a curb on the street. I start looking ahead, much farther ahead. I pick up my feet. I gain the confidence to hop over the uneven trail or jump off the curb. And that’s usually where the sweet spot for me is.”
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In the documentary The Great Dance: A Hunter’s Story, filmmakers captured a modern-day persistence hunt. A hunter named Karoha Langwane pursues an antelope for hours across the Kalahari Desert in 120-degree heat. Craig Foster, one of the film’s directors, expected that viewers would be disturbed by the scene where the antelope, chased to exhaustion, collapses in front of the hunter, who then drives his spear into the animal’s chest. But filmgoers were deeply moved by the scene and by the relief on Karoha’s face as his pursuit ends with the joy of knowing that he can feed his family and his tribe. As Foster told a reporter for ESPN, “People were overcome because they were seeing a deep, important part of themselves that they never knew existed.”
Witnessing this aspect of our human inheritance—the ability to persist so we can survive—can be an awe-inspiring experience. But it’s also something many runners and athletes glimpse directly when they choose to push past the inertia that makes it difficult to begin or the fatigue that tempts them to stop. Jody Bender told me about a recent hiking trip she and her husband had taken in Big Bend National Park in Texas. For three days, they carried the weight of their packs on their backs and covered fifteen miles through the mountains—something that would have seemed impossible back when Bender was in physical therapy, struggling to stay vertical on the balance machine painted to look like a mountain range. On that hiking trip, Bender fell a couple of times. “I was hot and I was uncomfortable, and everything hurt. I almost ran out of water,” she recalls. “But the second you finish, you don’t even really remember the uncomfortable parts. You remember that feeling at the end: Wow, I said I was going to do it, and it was hard, but I didn’t give up, and I did it, and that’s awesome.”
Persistence is key to experiencing a high while exercising, but maybe that’s not the best way to think about it. We don’t persist so we can get some neurochemical reward; the high is built into our biology so that we can persist. Natural selection has endowed us with a way to chase our goals and keep going even when it’s hard. The runner’s high is the temporary reward that carries us to our bigger goals. For many, the experience of persevering is part of what gives movement meaning and what makes the experience rewarding. This is the less heralded but perhaps most lasting side effect of the persistence high: You get to experience yourself as someone who digs in and keeps going when things get tough. This is how Jody Bender sees herself now, seven years after her stroke. She attributes much of the confidence she’s developed since then to running. “I know who I am,” she told me. “I don’t know that I did before.”
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Neuroscientists describe endocannabinoids as the “don’t worry, be happy” chemical, which gives us our first clue about what exactly an exercise high does to your brain. Areas of the brain that regulate the stress response, including the amygdala and prefrontal cortex, are rich in receptors for endocannabinoids. When endocannabinoid molecules lock into these receptors, they reduce anxiety and induce a state of contentment. Endocannabinoids also increase dopamine in the brain’s reward system, which further fuels feelings of optimism. As runner Adharanand Finn observes, “It may only be chemicals shooting around in your brain, but after a long run everything seems right in the world.”
Another way to understand what endocannabinoids do is to look at what happens when you inhibit them. The now-banned weight-loss drug Rimonabant blocks endocannabinoid receptors, an effective way to suppress appetite. In clinical trials, the drug led to alarming increases in anxiety and depression, as well as four suicides. The adverse effects on mood were so pervasive and severe that the drug was withdrawn from the European market and never approved in the United States. In a potentially unwise experiment, Vice reporter Hamilton Morris got his hands on Rimonabant to find out what the opposite of a cannabis high feels like. As Morris describes the effects of a sixty-milligram dose, “I have never felt so un-high in my life.” He is plagued by anxiety and nausea and finds himself on the verge of tears for no apparent reason. When Morris’s experiment ends, his recovery could be mistaken for a runner’s high. “The neurochemical floodgates have opened and there is unimaginable rebound euphoria,” Morris writes. “All night I walk down the street, peaceful and optimistic, ready to high-five strangers.”
Rimonabant can still be procured for scientific research, and if you give the drug to rodents who love to run, it dramatically decreases their wheel-running. (One such experiment gave some of the mice THC, the psychoactive ingredient of cannabis, instead of Rimonabant. THC didn’t have any effect on how much they ran, but it’s always possible it led to some interesting experiences on the wheel.) Blocking endocannabinoids also eliminates two benefits of the runner’s high: less anxiety and higher pain tolerance. Mice typically fear a new environment, but after running on a wheel, they are considerably braver when placed in an unfamiliar dark box. They also show less physical discomfort—jumping and licking their hind paws—when put on a hot plate. If mice are injected with a Rimonabant-like drug before they run, they don’t get these benefits. Instead, they act just as scared and hurt as mice who hadn’t exercised.
These findings provide further evidence that endocannabinoids make running rewarding. They also raise intriguing possibilities about the psychological effects of our own daily workouts. It’s easy to notice and savor the peak high, but we might not recognize how its underlying brain chemistry is preparing us for what comes next. The National Study of Daily Experiences tracked the physical activity and moods of over two thousand adults in the United States, age thirty-three to eighty-four, for eight days. Every night they called participants and asked them about the most stressful events of that day. On days when people were active, stressful events—such as conflict at work or taking care of a sick child—took less of a toll on their mental well-being.
In laboratory experiments, exercise can even make you immune to the panic attacks typically induced by CCK-4, a drug that triggers severe anxiety and physical symptoms like a racing heart and breathlessness. The effect of exercising for thirty minutes before being exposed to CCK-4 is equivalent to taking a benzodiazepine like Ativan, but without the sedating side effects. Think about that: Physical activity can counteract anxiety that has literally been injected into your bloodstream. I am not a morning person, but I have learned to drag myself out from under the covers, stumble to the kitchen for coffee, and exercise before I do anything else. For me, it’s a survival strategy. I want to face the day as the version of myself who takes over by the time I’m done with my workout: braver, more optimistic, and ready to face whatever challenges await me.
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Niki Flemmer, a thirty-seven-year-old nurse practitioner in Seattle, had gotten into a rut running a 5K on the treadmill at her gym every day. She was sick of doing the same workout by herself all the time when she heard about a local studio that offered group treadmill and rowing classes. “It sounded hard, and I didn’t know if I could keep up with the intensity,” she rememb
ers. But she was also at a time in her life when she was committed to doing things that scared her, so she decided to check the studio out.
During class, everyone works at a pace that is challenging for them. One person might be running a seven-minute mile while another walks a fifteen-minute mile. Flemmer was delighted to find that in the group setting, the same physical movement means something different than it does when she exercises alone. It feels like everyone in the class is pursuing a collective goal, putting in the effort not just for themselves but also to support one another. One of her favorite parts of the workout is when the coach calls for an all-out attack, and she looks at the person on the treadmill next to her and says, “Let’s kill it!” “When I see twelve people giving it their all, I often am so moved, I get tears in my eyes.”
The studio is lined with mirrors, and during a recent workout, Flemmer made eye contact with a man on the treadmill behind her. “We had that moment of absolute connection, with gestures to indicate we were cheering each other on. I felt grateful. Grateful for him and his ability to show up for himself, and grateful for the human capacity to connect.” This feeling lingers after class ends. “I feel more brave out in public, to make eye contact and engage people more,” she told me. “It’s helping me realize that everyone wants connection. Even though they might not admit it, people like it when you smile at them.”
Social confidence may seem like a surprising side effect of breaking a sweat, but the chemistry of a runner’s high primes us to connect. In a 2017 review of how the endocannabinoid system works in the brain, scientists identified three things that reliably amp it up: cannabis intoxication, exercise, and social connection. The three psychological states most strongly linked to low levels of endocannabinoids? Cannabis withdrawal, anxiety, and loneliness. Endocannabinoids aren’t just about not worrying and being happy; they are also about feeling close to others. Higher levels of these brain chemicals increase the pleasure you derive from being around other people. They also reduce the social anxiety that can get in the way of connecting. And just as inhibiting endocannabinoids eliminates the runner’s high, it also takes away the desire or ability to connect with others. Giving rats an endocannabinoid blocker makes them less interested in socializing with other rats. In mice, it makes new mothers neglect their pups.
A runner’s high does the opposite: It helps us bond. Many people have told me that they use running as an opportunity to connect with friends or loved ones. John Cary, a forty-one-year-old writer and father of two, fondly remembers taking his young daughter on runs. He would put her car seat in a jogging stroller and push her up the hills and along the outdoor trails of their hometown of Oakland, California. Sometimes they practiced making animal sounds, and other times he told her about all the people in the world who loved her. “Over the course of a run, I’m able to name fifty or sixty people in her life. Whether or not she’s processing it is another question, but I just love those times we have together.”
I’ve also heard from many people who rely on a daily workout to be more caring parents or partners. After exercising, they return to their families refreshed and ready to connect. As one runner notes, “My family will sometimes send me out running, as they know that I will come back a much better person.” One study found that on days when people exercise, they report more positive interactions with friends and family. Among married couples, when spouses exercise together, both partners report more closeness later that day, including feeling loved and supported.
When I came across the research linking endocannabinoids with social connection, I thought about something else anthropologist Herman Pontzer had told me about how early humans adapted to a changing landscape. He’s convinced that running is not the only factor that helped them survive. “If you had to pick one behavior that marks the beginning of hunting and gathering, that is the game changer,” he said. “It’s sharing.”
Hunting and gathering, both as it’s done among the Hadza today and as we imagine it was done hundreds of thousands of years ago, is a division of labor. Some members of the group go out hunting, while others do the more reliable work of foraging for plants. “You bring those together at the end of the day, and you share, and everyone has enough to eat,” Pontzer said. Groups who were better at sharing were more likely to survive, and natural selection started favoring not just traits that enhance physical endurance, like longer leg bones, but also traits that encourage within-group cooperation. That’s why humans have such big whites of the eyes; it helps us communicate through eye contact.
Another such adaptation is a neurobiological reward for sharing and cooperating, one that looks an awful lot like the runner’s high. Mutual cooperation activates brain regions linked to reward, releasing a feel-good chemical cocktail of dopamine, endorphins, and endocannabinoids. Call it a cooperation high: It feels good to work with others toward a shared goal. Brain-imaging studies show that when you see the face of someone with whom you previously cooperated, it reactivates your reward system. From an evolutionary point of view, this is the neurobiological foundation of trust. It’s also a kind of anticipatory high. No doubt this is part of why Niki Flemmer experiences so much joy in her group running and rowing classes. Her brain’s reward system kicks in as soon as she steps into the gym and sees the face of someone she high-fived or cheered on in a previous workout.
Sharing may also be a pleasure that that draws people to exercise in groups. A woman who practices jiujitsu told me that one of her favorite parts of training is the tradition of sharing gear. “Jiujitsu gyms are like a family, and shared gear is important. It’s how you’re welcomed.” Her first gi, the heavy cotton jacket that practitioners wear, was borrowed from a friend. Her mouth guard was a gift from another student at the gym. Taking what is offered is part of how you belong. “It’s okay if you don’t have something yet,” she said. That gives others a chance to let you know, “We’re here for you.”
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Evenings in Hadzaland are spent around campfires. It’s a time to unwind after a day of risk-taking hunts and focused foraging. Scientists will tell you that sitting around a fire encourages social bonding. The warmth, the flickering flames, and the crackling sounds lull us into a state more receptive to the pleasures of connecting with others. As I thought about the Hadza’s evening rituals, I began to wonder: What if the runner’s high does something similar? Could the afterglow of physical activity make you feel more warm and fuzzy about the people you share your life with? And make coming together at the end of the day, to share stories and a meal, even more satisfying?
It seemed to me that a runner’s high fueled by endocannabinoids wouldn’t just make hunting and foraging more enjoyable. By priming you to connect, the high should also make sharing the spoils with your tribe more rewarding. An experiment at the Sapienza University of Rome suggests that physical activity can have this effect. Participants played an economic game that required contributing money to a communal pool. The more they contributed, the more all parties would benefit. Participants who exercised for thirty minutes before playing the game shared more than when they played the same game without exercising first.
I ran my hypothesis—that the runner’s high encourages cooperation and bonding—by anthropologist David Raichlen. He thought it was plausible that exercise-induced endocannabinoids contribute to social cohesion. In fact, he had been itching to run a study looking at whether exercising with others would lead to a bigger increase in endocannabinoids than exercising alone. But I was even more interested in another possibility—that being physically active can enhance the cooperation high and help us extract even more joy from working as a team or helping others. As it turns out, I wasn’t the first to consider this proposition. When you bring together the runner’s high and the helper’s high, the rewards go beyond a more satisfying workout. Runners become family, communities get cared for, and humans find their tribe.
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sp; •••
Nykolette Wallace, a thirty-five-year-old administrator for the National Health Service, was running through the streets of Southeast London in a torrential downpour. Heavy rain hadn’t been expected until later that evening, and she was not dressed for the weather. Her hoodie and baseball cap were inadequate defense against the deluge, and soon she was soaked. Wallace was running with a pack of volunteers for GoodGym, a London-based organization that combines running and community projects. The group was running through Wallace’s own neighborhood of Lewisham to the Goldsmiths Community Centre, which provides locals with preschool, prayer groups, ballroom dance classes, chicken lunches with bingo, and sobriety support. On the way to the center, the group ran right by Wallace’s home, and she was tempted to abandon the pack, dry off, and get warm. But there was so much camaraderie, she didn’t want to leave. “Humans, we moan a lot: ‘It’s raining, I want to get inside.’ We were all out there, everyone still laughing and chatting,” she remembers. “We were going to do something good because we all wanted to. Nothing else mattered.”
The founder of GoodGym, Ivo Gormley, used to watch exercisers running to nowhere on treadmills in gyms, and think, What a waste of energy. He wondered if there was a way to harness that energy. As a first experiment, Gormley sent volunteer runners to visit socially isolated older adults in London. According to government data, half the older adults in the UK say that television and pets are their only companions, and many leave the house less than once a week. Two hundred thousand older adults in England and Wales have not spoken with a friend or family member in more than a month. As one person who requested visits from a GoodGym volunteer explained, “It would be very nice to see another human being. My only friends are people on the telly.” The older adults who receive visits are given the title of “coach.” Their role is to keep the runners motivated by giving them somewhere and someone to run to. The runners make regular social calls to their coaches and, when needed, help out around the house with things like changing lightbulbs. Over time, these visits turn into real friendships. More than once, when a coach has fallen ill, GoodGym runners have been their only visitors in the hospital—and at discharge, they are often the ones who take the coaches back home. Sometimes the tables are turned, and it’s the coach who shows up to support a GoodGym runner.
The Joy of Movement Page 3
