When we exercise, our heart rate quickens and increases blood flow to the brain. The effect is immediate: the brain pumps out a series of chemical messengers – serotonin, dopamine, among others – that enhance vigilance, block pain signals, bring pleasure. A flood of endorphins, the body’s natural opiates, might induce a state of euphoria: discomfort dissipates and peace sets in.
Exercise is medicine, for the brain and body. Its absence is the reverse. Even in pre-Covid times, illness from physical inactivity was responsible for around one in six UK deaths, about 100,000 a year; post-pandemic, we are even more aware of the dangers of sedentary lifestyles, with obesity increasing the risk of death from Covid by 48 per cent. We need exercise, for all its physiological benefits and the ones we can’t scan or weigh: for me, fitness is about self-regulation; for others, it’s about mental toughness, community, competition.
But like anything else that makes us feel good, exercise can be addictive. It’s not for nothing we refer to the rush of happy brain chemicals after strenuous physical activity as “runner’s high”. For some, this high is desperately and dangerously pursued. Physical activity becomes, as one specialist puts it, life’s “main organising principle”, a pathological pursuit of movement to which everything else – work, relationships, recovery – is subordinated.
Exercise addicts suffer deep psychological and physical distress: marriages break down, menstruation ceases, disks are herniated and bones are weakened and snapped; the prospect of a day without fitness seems like a fate worse than death, certainly worse than chronic injury.
And although exercise addiction is rare – affecting 3 to 7 per cent of the exercising population (rising to 25 per cent of runners and 50 per cent of marathon runners and triathletes) – research suggests around half of people with an eating disorder engage in compulsive exercise, and are four times more likely to become addicted to it than others. Together, the disorders can be life-threatening.
It is a curious thing to be addicted to something that is good for you. No one tells a gambling addict they should place bets every day to be healthy, and no one praises them for the hours they spend making them. Since exercise is not naturally incorporated into the structure of a white-collar workday, those rare bursts of activity should, we’re told, be hard and fast, the better to offset all the desk-time. Over-exercise is not only socially acceptable – it is actively encouraged by our “more is better” culture; more exertion, more minutes, more lifting, sweating, slimming. Fitness instructors tell us to push harder and past the pain; adverts glamourise addiction in the hope that we will buy stuff.
Compulsive exercisers live in a bind in which their addiction is both positively reinforced and treated as non-existent. Exercise addiction isn’t officially classed as a clinical disorder; indeed, the only behavioural addictions recognised by the World Health Organisation’s International Classification of Diseases (ICD) and the US’s Diagnostic and Statistical Manual – the handbook for psychiatric professionals – are gambling and internet gaming disorders, with clinicians still debating whether, for example, compulsive sex or shopping can be labelled “addictions” and therefore pathologised.
But there is also an argument that “natural” compulsions, stemming from needs such as sex and food, hijack our brain’s reward circuit in much the same way substance addictions do, with similar mood-altering neurochemical effects. And excessive exercise fits the pattern in more ways that one.
According to the authors of The Truth about Exercise Addiction, aspects of compulsive exercise bear other hallmarks of addiction beyond the neurochemical changes in the brain: tolerance (the initial effect wears off, so doses are upped to try and regain it); withdrawal (headaches, fatigue, irritability); continuance (exercising through injury, thereby disconnecting from the body’s needs), among others.
In the book, Heather Hausenblas, a professor of kinesiology (the study of body movement), and writer Katherine Schreiber describe the harms of exercise addiction, from the destruction of social and professional lives to the extreme restlessness of withdrawal and physical injury. “Joints and muscles are the first physical victims,” they write, followed by bones – fractures, breaks, osteoporosis – and other health problems linked to overuse and overzealous activity, from tendinitis to cardiovascular problems. Indeed, research suggests there’s a U-shaped relationship between exercise and cardiac morbidity: according to one study, running between one and 20 miles a week can significantly reduce mortality rates, but regularly doing 25-plus miles weekly carries a similar risk of death as not exercising at all.
Despite this evidence, the seriousness of exercise addiction is often doubted or downplayed. I think it matters – I’ve done the reading – but I would be tempted to shrug and say, well, aren’t there worse things? Compared to other addictions, its impact seems mild: over-exercise won’t give you cirrhosis of the liver, make your teeth fall out, induce psychosis; it’s unlikely to mean patients inflict harm on others, lose their life savings or turn to crime. Its toll on society is limited.
Yet, it is precisely for this reason that we should pay attention to compulsive exercise, and to all the other disputed pathological behaviours: they reveal something about the way we hierarchise, politicise and validate addiction, and the way we invalidate it too.
Schreiber and Hausenblas set out two types of exercise addiction: primary, which is not motivated by weight or calorie control; and secondary, which is in the service of an eating disorder.
Schreiber, 32, a social worker assisting adults with severe mental illness, is still recovering from her own exercise addiction. A few months ago she underwent shoulder surgery following years of obsessive yoga (“Yoga!” she says, “Like, how do you get addicted to yoga?!”) – the latest in a string of injuries she refused to let heal.
Her addiction was tied up with disordered eating and body image issues dating back to childhood. She struggled behaviourally and, at 13, was sent to a residential facility for “troubled girls”, where eating disorders, she says, were like a social contagion.
“I saw self-driven exercise as a way to control my body,” she tells me. Two workouts a week became two or more hours in the gym a day; she’d cancel social plans for extra sessions, or else she’d sneak out of the cinema to do push-ups in a public bathroom.
Schreiber had no desire or energy for friendship: anyone close enough to notice she had a problem became a threat to her exercise schedule, so she would distance herself from them. Over-exercise, which in men can lead to lowered libido, can also cause exhausted addicts to shun romantic partners and physical intimacy. Schreiber believes one way to understand what drives exercise addicts is “this terror of vulnerability and intimacy”. “When you’re that addicted to something it doesn’t let anything in,” she says. “And that’s kind of the point.”
There are other things at play. Whereas most theories of addiction tend to assume it involves a loss of control, Schreiber was “addicted to the rigidity” of exercise. Workouts took place at a certain time in a certain way – cardio before weights, weights in the same order – all of which built methodically towards the promised high: psychological pain soothed, even as physical pain was aggravated.
“The real driver for me was the reduction of anxiety,” she says. “From the moment I woke up, I’d be stressed, and I’d have to do my workout. It was like I was in flight or fight mode, and was seeking relief from it.”
Fight or flight, strength and speed – exercise, on an evolutionary level, is the natural manifestation of a biological stress response designed to make the body move. But the process can become self-perpetuating: if the exercise response is built into the flight-flight response, how do you begin to separate the means, the cause and the object of addiction?
“I have a trauma history and most of the people I interviewed for the book had a trauma history,” Schreiber says. “Most people with addiction have a trauma history. So we’re talking about people who have a heightened fight-flight response, people who are in survival mode.”
Exercise acts on and reduces this feeling, Schreiber says. “We’re out of fight-flight mode, we’re OK for five minutes. Then we have to do it again.”
Lisa Fouweather ran half marathons before breakfast. She ran six times a week, and on her “rest day” did two hours of strength training. There were two-hour daily ab workouts, plus 70,000 steps, and Fouweather did every one of them, in spite of sickness, fatigue, or stress fractures in her feet.
Fouweather, now 19, used to be among the UK’s top 50 runners for the 3,000m event. Understanding lighter meant faster, she started restricting her diet, developing orthorexia and became severely underweight. But the running didn’t stop. At the age of 16 Fouweather was sectioned; in hospital, her heart rate dropped to near-fatal levels.
Many people look at the extraordinary achievements of endurance athletes and wonder what drives them. For Fouweather, it was a pathology. This is clear now, but at the time it wasn’t; at school and her athletics club, she was simply “the runner”, someone who took her sport seriously.
“I definitely think, had I not been a competitive athlete, but more of a recreational runner, my exercise levels would’ve been questioned a lot earlier than they were,” she says.
“Unfortunately, as is the case with most clubs, eating disorders and exercise addiction are very rarely talked about, so people don’t know how to react. I was never made to stop participating in club races. In fact, I was encouraged to by the club chairman.”
Fouweather’s compulsion was encouraged away from the track, too – on social media, where she found an opportunity for comparison and obsession. “If I went on Instagram and saw someone I followed had just gone for a ten-mile run, when I’d only done three, I’d feel an urge to go back out to do more than they’d done,” she says.
Instagram is dominated by fitness accounts – there are more than 70 million posts under the #fitspo hashtag – and influencers, many of whom have spoken about their own exercise addictions and eating disorders, have discovered a lucrative market promoting jump squats and gym leggings to thousands of aspirational users. Meanwhile, research shows fitness apps and trackers such as Strava and Garmin increase the risk of exercise addiction among athletes; gamification makes the tech “sticky”, and divorces users from “real-life” goals. What begins to matter most is the data, the mileage on the screen. What the body wants quite literally doesn’t register.
[See also: The dark side of our age of fitness]
Stigma is a key barrier to successful treatment engagement for excessive exercise – both Fouweather and Schreiber talk about the embarrassment they felt, how sufferers are put off seeking help for fear they won’t be taken seriously. Some argue officially recognising compulsive behaviours such as exercise addiction as pathologies might help prevent this, encouraging self-labelling and reducing self-stigma by presenting the disorder as an involuntary illness, rather than a failure of character which the individual feels blamed for.
However, Stuart Sadler, a clinical psychologist based in Newcastle, thinks it is more useful to view excessive exercise as a habit or compulsion. “Labelling it as an addiction creates a lack of control and a ‘me versus it’ mentality which can lead to more stress, and we know that fighting our brain doesn’t work,” he says. “A more helpful therapeutic approach is to see over-exercise as a coping strategy that has gone into overdrive or is being used as the wrong tool for the job.”
He recommends cognitive behavioural therapy (CBT) as well as treatment focusing on underlying drivers. Schreiber found 12-step programmes and dialectical behavioural therapy, designed for people with borderline personality disorder, useful in her recovery. DBT teaches mindfulness and distress tolerance, and shows patients ways, other than exercise, to help regulate the nervous system: interventions such as holding ice cubes to one’s temples or snapping a rubber band “regulate the human who is dysregulated so they can engage in something like CBT”, she says.
Where treatment for other addicts might involve total abstinence, the necessity of physical activity, when it’s not being abused, means going “cold turkey” is neither desirable nor feasible; instead, treatment taps into motives, working out ways to help patients exercise responsibly.
What everyone I spoke to agreed on is the unhelpfulness of the “more is better” message, which features in the UK government’s official “tackling obesity” guidance. “Everything in moderation” is true for exercise too, and while a risk/reward calculation is necessarily built into public health strategy, so too should sensitivity be. Schreiber would like to see a nod to the risks of obsessive over-exercise written, even in small print, into guidelines, an awareness that could also instruct the institutions that facilitate our practice of exercise: gyms and athletics clubs could, for example, stress the importance of rest days and have clear guidelines on how to respond to eating disorders and exercise dependence.
“I wish scientifically we could have a broader discussion about what an upper limit to exercise would look like,” Schreiber says. With more research, she hopes we might start to talk about an optimal range of exercise, from the recommended 150 minutes of moderate intensity activity a week to the number of hours at which “physical exertion has negative effects”.
Schreiber still exercises every day. “I can’t lift weights any more because of my shoulder injury,” she says, “but I don’t feel as obsessive or controlled by my exercise schedule as I used to.” Despite the constraints on her body resulting from years of overexertion and obsessive yoga, Schreiber concludes: “I’m more flexible now.”
[See also: The dark side of the wellness industry]