Haefele isn’t fast. “Typically in a race, the gun goes off, and I’m alone within five minutes, and I’m alone until the end of the race,” she says. She often crosses the finish line last, but she’s found that most people cheer even harder for runners at the end of the pack. “I don’t mind finishing last so someone else doesn’t have to.” She takes particular pride in persevering. At one half marathon in Harrisburg, it was raining so hard that the puddles were ankle deep and drivers were forced off the road. Haefele was the final runner to reach the finish line, but she earned first in her age group because everyone else in her category had backed out.
Haefele, a tax accountant, first started walking on a treadmill at work, but quickly realized that exercising indoors wasn’t for her. She looked for something that would get her farther from her cubicle and discovered volkssporting, German for “the people’s sports.” Volkssporting takes a noncompetitive approach to outdoor walking, hiking, cycling, swimming, and cross-country skiing. You can show up at an event any time within the start-to-finish window, participate at your own pace, and take in the scenery and the company. Haefele started participating in 10K walks throughout the United States, enjoying both the travel and the people she met. To challenge her fitness more, she registered for her first timed race, a 5K walk. “When I signed up, I was terrified,” she remembers. “I thought, It’s going to be all six-foot-tall twenty-year-olds, and they’re going to look at me and say, ‘What is that fat old woman doing here?’” To her relief, it wasn’t like that at all. She felt welcomed, finished the race, and realized, I can do this.
With more training under her belt, she signed up to walk a half marathon in Birmingham, Alabama, just “to see what it felt like.” She was surprised to find that she enjoyed that, too, and decided to try running. “There have been times when I’ve been out there at mile ten, thinking, Why did I think this is fun? This is horrible. Other times I’m on cloud nine. I feel strong. I feel powerful. I’m accomplishing something. When I approach the finish line, I feel great.” After Haefele passed the milestone of her seventy-fifth half marathon, she decided to aim for a hundred. “My races are a source of joy. At sixty-one, I feel privileged to feel that way.”
When I asked Haefele if the races reminded her of anything, she instantly said, “Church. It’s my way of celebrating the world. We’re all out there celebrating, and sort of worshiping what’s been given to us, and we’re all grateful. It reminds me of a church service.” After a pause, she added, “It’s also like going to a rave. After a race, I’m in love with everybody, and sometimes it lasts the whole day. The person who’s selling me a coffee at the convenience store on the way home, I’m like, ‘I love that guy.’ I’ve never done ecstasy, but that’s how I imagine it is: All’s well with the world, everybody’s wonderful. If all you have to do is run thirteen miles to get that, it’s so worth it.” Haefele is a recovering alcoholic, and she hasn’t had a drink since 1988. “This is now my drug of choice,” she told me. “It fills the same need, but it does it in such a good way.”
Haefele never expected to get hooked on racing. She was born in 1957 and went to school before Title IX, passed as part of the Education Amendments of 1972, which requires schools to offer the same athletic opportunities to girls and boys. “I always thought, ‘Sports aren’t for girls.’ If you had told me in high school that at some point I’d be doing races, I would have thought you were insane. I thought I wasn’t supposed to, that it wasn’t for me. I was fat, too, and that makes you sometimes think, that world isn’t for me, I’m not allowed to be there,” she says. “Somewhere along the way, I thought, Screw that. I’m going to go do stuff. Why am I limiting myself? When you turn fifty, you stop worrying about other people. I don’t know why I wasted my whole life thinking I wasn’t allowed to do athletics because I was a girl and I was fat.”
Now when Haefele hears that someone is thinking about trying a first 5K but is worried about finishing or belonging, she encourages them to take the risk. “I tell them the story about my first 5K, how afraid I was, and how it literally changed my life. If I can, I will offer to go with them,” she says. “I like to throw in John Bingham’s quote, ‘The miracle isn’t that I finished, it’s that I had the courage to start.’ I get weepy when I see that. If you can just find that little bit of courage that you need to start, it will change everything.”
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Whenever Nora Haefele drives past the exit for a race she has run, a warm and happy feeling floods her body. “I’ll remember the day I did it, the weather, the people I saw, and how I felt when I finished,” she told me. In 1976, marathon runner Ian Thompson told New York magazine, “I have only to think of putting on my running shoes and the kinesthetic pleasure of floating starts to come over me.” Both Haefele’s response to highway exits and Thompson’s anticipatory runner’s high point to one of the more curious similarities between addiction and exercise enthusiasm: the conditioned rush that scientists call the pleasure gloss. When you repeatedly experience a smell, sound, taste, sight, or touch in a context that is highly enjoyable, that sensation gets encoded in your memory of the pleasant experience. Eventually that sensation—even if it was originally neutral or unpleasant—becomes interpreted by the brain as highly pleasurable all by itself. Once this association is formed, ordinary sensory stimuli become pleasure bombs, setting off explosions of endorphins and dopamine. Consider, for example, the way NASCAR fans come to not just tolerate but savor the olfactory assault of burnt rubber. Or how a grown child whose parent baked still associates the whirring of a standing mixer with feeling safe and loved.
In the case of addiction, sensory cues can trigger powerful cravings or even withdrawal. The mere sight of drug paraphernalia or the smell of a place where someone has repeatedly gotten high can set off an intense desire to use. Psychiatrist Benjamin Kissin noted that when former heroin addicts returned to New York City after being incarcerated in Sing Sing for five years, they developed spontaneous withdrawal symptoms as soon as the train passed through their old neighborhoods.
Exercise enthusiasts report their own versions of the pleasure gloss and cue-dependent cravings. Sensations associated with exercise become highly pleasurable, and objects, places, or other cues related to a favorite activity can produce a strong desire to move. When I asked people I knew for their own examples, many offered odors: the chlorine of an indoor swimming pool, the scent of freshly cut grass on a soccer field, even the manure on a farm where one woman rides horses. A former student of mine said the smell of his yoga mat sets off his brain’s pleasure circuit. When I asked what his mat smelled like, he said, “Rubbery chemicals,” proof that the brain is willing to give anything a pleasure gloss. Other exercisers take satisfaction in sounds: the clank of heavy weights being dropped in the gym, the pop! of opening a can of tennis balls, or the click of cycling shoes locking into pedals. The source of pleasure could even be an object, such as the exercisers who recounted to me the gratification of a favorite running shirt (“When I put it on, I feel invigorated”), a yoga rug (“When I pack it into my bag the night before, I feel a sense of excitement for the next day . . . I definitely feel that happiness buzz when I touch the rug”), and a heart rate monitor (“When I plug it in to charge, I start to feel excited, in fact just thinking about it now is making my stomach have a few butterflies. When I have it in my hand, I feel a charge of empowerment”). How strange these statements must seem to the person who hasn’t yet gotten hooked on any physical activity. I myself was surprised by how easily exercisers identified their own pleasure glosses. And yet these examples demonstrate just how genuine the reward of physical activity is. A brain makes such leaps and forms such associations only when the pleasure runs deep.
My own most deeply ingrained exercise-related anticipatory pleasure is the feel and sound of putting a VHS cassette in the VCR. I first discovered what was then called aerobics in the third grade when my mom started bringing home exe
rcise videos she picked up at garage sales. At first she bought them for herself, imagining a future fitness kick that never materialized. I was the one who got hooked on the synthesized music and synchronized movements. In gym class and on the playground, I was uncoordinated, clumsy, and seemingly lacking in all athletic talent. But the workouts in these videos tapped into physical skills that no kickball game or shuttle run had ever called for: the ability to move to a musical beat and a knack for mirroring another person’s movements. Doing these videos, I discovered the thrill of physical competence, so different from the humiliation of being unable to catch a ball or do a flip on the jungle gym bars. Doing leg lifts, I felt like a Rockette in the glamorous Radio City Music Hall Christmas Spectacular my grandparents had taken my sister and me to in New York City.
Much later on, when I became a psychologist, I would learn that the capacities to keep a beat and mirror other people’s movements are both related to empathy. The workout videos tapped into the same personality trait that helped me lose myself in novels like Julie of the Wolves and kept me up at night worrying about the starving children we collected change for in UNICEF boxes. By doing so, calisthenics and dance aerobics gave me access to my body’s intelligence in a way that competitive playground sports never had.
Over the years, I amassed quite a collection of tapes, stacking them up in the corner of the television room. (The original Jazzercise was a favorite of mine, in part because the instructor encouraged us to sing along as we danced and stretched.) I kept up a daily routine well into high school. Before each workout, I’d scan the stack, select a video, and slide it out of its cardboard case. After I inserted the video into the VCR, there’d be a satisfying click as the machine accepted the cassette, then the sound of the machine lifting the cassette’s protective flap to expose the tape. By the time the TV screen came to life with the old FBI copyright infringement warning, my brain cells were awash in dopamine. I no longer have a VCR, but if you put one of my old aerobics videos in my hand, I’m sure my brain would remember the pleasure and my heart would beat faster in anticipation of step-touches to come.
Exercisers tend to experience these conditioned responses in a very different way than drug users who are trying to stay clean, perhaps because most feel no ambivalence about their habit. They welcome the cravings set off by a pleasure gloss and relish the way familiar sensations ignite their desire. These sensations are not triggers for an uncontrollable and self-destructive compulsion. Instead, for many exercisers, the pleasure gloss that coats ordinary sounds, smells, and objects serves to remind them of a long-standing and positive relationship they are grateful for. As one friend described his own pleasure gloss to me, “The martial arts academy where I’ve trained for fifteen years has a very unique smell—some combination of sweat, rubber from the mats, and Lord only knows what else. If I’ve been traveling for a bit and then return, my body reacts as if I’ve come home after being away a long time.” His comment reminded me of the research showing that seeing a friend’s face can set off the brain’s reward system. That burst of dopamine and the subsequent rush of pleasure help solidify the relationship. Perhaps the same is true for each of the beloved sensations that exercisers savor. The feel of a favorite T-shirt’s worn threads on your skin, the sound of a yoga mat unfurling and hitting hardwood floors, the mingling smells of sweat and wax as you step onto a basketball court—they deepen the pleasures inherent to movement and bond us more strongly to our activity of choice.
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When my husband decided to train for a triathlon a couple of years ago, he started reading books and listening to podcasts about endurance sports. As he shared his favorite stories, one thing that stood out was how many of these athletes were in recovery from drug or alcohol addiction. Perhaps for some of them—such as the runner who compared the high of long-distance running to heroin—exercise is a substitute addiction. But it occurred to me that something else might be going on; that perhaps exercise can repair the neurological havoc wreaked by previous addictions.
Drugs of abuse would be far less destructive if all they did was teach your brain to want them. Their actual effects are more devastating, in part because when a substance unleashes an unnatural flood of feel-good chemicals, it triggers the brain’s homeostatic mechanisms. Your brain will try to compensate for the drug’s effects to keep your neurochemistry in balance. One way it does this is by activating the brain’s anti-reward system, which works to dampen the effects of feel-good chemicals. The anti-reward system initially kicks in when the brain is flooded with abnormally high levels of dopamine or endorphins. The brain is attempting to reduce the extreme high, like pulling the plug in a bathtub so it doesn’t overflow. When you regularly trigger the anti-reward system through repeated drug use, you teach the system to stay activated even when you aren’t using. A brain that is used to being put in a state of extreme high will begin to kill your joy preemptively, producing a near-constant dysphoria. Chronic drug use also lowers the level of dopamine circulating in your brain and reduces the availability of dopamine receptors in the reward system. Both of these changes can leave you feeling unmotivated, depressed, antisocial, and unable to enjoy ordinary pleasures—a consequence neuroscientists have labeled the dark side of addiction.
Here’s where the long-term effects of physical activity and substance abuse most dramatically diverge. Exercise produces a less extreme spike in dopamine, endorphins, and other feel-good chemicals. Drugs like cocaine or heroin wallop the system, but exercise merely stimulates it, leading to very different long-term adaptations. The brain reacts to regular exercise not by suppressing activity in the reward system, but by facilitating it. In direct contrast to drugs of abuse, exercise leads to higher circulating levels of dopamine and more available dopamine receptors. Instead of annihilating your capacity for pleasure, exercise expands it. The sensitization of the reward system to nondrug rewards such as food, social connection, beauty, and any number of ordinary pleasures may explain why exercise helps people recover from substance abuse. In both animal and human studies, physical activity reduces cravings for and abuse of cannabis, nicotine, alcohol, and morphine. In one randomized trial, adults in treatment for methamphetamine abuse participated in an hour of walking, jogging, and strength training three times a week. After eight weeks, their brains showed an increase in dopamine receptor availability in the reward system.
Studies like this suggest that exercise can reverse the anti-reward system’s takeover of the brain and bring a numbed reward system back to life. In doing so, exercise resembles not so much a habit-forming drug of abuse as an antidepressant. The closest parallel I could find to how physical activity affects the reward system is not addiction, but continuous deep brain stimulation, one of the most promising medical treatments for depression. To prepare a patient for deep brain stimulation, a neurosurgeon drills a small hole into a patient’s skull and slides an electrode into the patient’s medial forebrain. The electrode is connected to a pulse generator surgically implanted in the patient’s chest wall. The generator delivers continuous low-level voltage to the brain’s reward system, much like a cardiac pacemaker regulates the beating of a patient’s heart. Over time, deep brain stimulation remodels the reward system to make it more responsive and has been shown to cure even long-standing, treatment-resistant depression.
A meta-analysis of twenty-five randomized clinical trials concluded that exercise has a large and significant antidepressant effect among people diagnosed with major depressive disorder. Another review of thirteen studies—conducted in the U.S., the UK, Brazil, Germany, Norway, Denmark, Portugal, Italy, Spain, and Iran—found that adding exercise to treatment with antidepressant medication leads to larger improvements than medication only. While there are many ways physical activity can affect mood, its impact on the reward system almost certainly contributes to its antidepressant effects. One way to think about exercise is that it is a kind of do-it-yourself deep brai
n stimulation. When you exercise, you provide a low-dose jolt to the brain’s reward centers.
Jump-starting the brain’s reward system benefits not just those who suffer from depression or those who have struggled with drug abuse. Our brains change as we age, and adults lose up to 13 percent of the dopamine receptors in the reward system with each passing decade. This loss leads to less enjoyment of everyday pleasures, but physical activity can prevent the decline. Compared to their inactive peers, active older adults have reward systems that more closely resemble those of individuals who are decades younger. This may be one reason exercise is so strongly linked to happiness and a reduced risk of depression as we get older. It may also explain why people who eschewed exercise earlier in life find themselves drawn to it as they age. The same mind-altering properties that make the “drug” of movement an addictive pleasure to some makes it powerful medicine for others.
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In 1993, Theodore Garland Jr.—the biologist who would, twenty-five years later, tell The New Yorker that he dreamed of a drug that could motivate people to exercise—started a selective breeding experiment with mice. Given access to wheels, mice will happily run, but Garland wanted to produce a genetic line that would run even more than the typical mouse. The earliest generations ran an average of four kilometers a day. By breeding only those mice who ran more than that, Garland’s lab was able to select for and strengthen whatever genetic factors compelled them to run. By the fifteenth generation, Garland’s mice were running fifteen kilometers a day. (A six-foot-tall man would have to run 168 miles a day to cover an equivalent distance for his body length.) Twenty-nine generations later, these selectively bred mice—known as “super-runners”—not only ran farther but also ran faster, ran more frequently, and took fewer breaks. If a lab assistant locked the running wheel so it would not rotate, the frustrated mice would climb the inside of the wheel in an attempt to run.
The Joy of Movement Page 5
