It was when, on a dark, freezing Tuesday evening in November, I found myself walking laps around the block a few hundred metres from my flat that I began to wonder whether something might be wrong. I was on my way home from the gym, but my Garmin watch was telling me I was still a few hundred steps short of my daily goal.
Rationally, I know that what I should have done is simply carry on my walk home. I am aware that, as an active, young person, there is no material improvement to my health to be achieved by walking, relatively slowly, for three extra minutes at the end of the day. In fact, taking into account the film of pollution permanently lingering over my congested north London high street, it is likely a net negative for my overall wellbeing. And yet, in the lashing wind and rain, I walked.
It is hardly a particularly disturbing, nor uncommon, tale. But, I recognised in it, the inchoate rumblings of something far more unsettling – the potential for that harmless three minutes of walking to develop into something far more sinister.
According to a 2022 survey, more than a quarter of adults in the UK now own a fitness tracker. Of that population, one-third of us wear these watches daily – including me. The global smartwatch market is lucrative and growing, projected to reach $62 billion (£49 billion) by 2028. In September, Oura Health Oy, the Finnish company which owns Oura rings, a popular new fitness tracker, announced it would see its annual sales double this year to roughly $500 million (£396 million).
As the market has grown, so the insights offered by these watches have become ever more elaborate. From the number of steps you take and the speed your heart beats, to the number of hours you sleep and your maximal oxygen consumption, there is no end to the data offered by trackers from brands like Garmin, Fitbit, Apple and Oura.
These trackers can be powerful tools: they help people feel motivated to get out there and move their bodies. And the data they offer can aid those suffering from chronic conditions such as migraines, to track their sleep cycles, in order to monitor and manage their symptoms.
However, research has also shown that these devices can also reinforce body-image issues and unhealthy obsessions, ranging from symptoms of disordered eating to obsessive preoccupation with fitness goals. A 2019 study from the University of Copenhagen revealed that many people depend on fitness tracker data as if it were medical advice, often sparking unnecessary fear and anxiety. With smartwatches specifically, these dopamine hits can come from closing your activity rings or feeling your device vibrate to let you know you’ve stayed under your allotted calories.
“Fitness trackers tap into our brain's reward system by providing immediate feedback and quantifiable achievements,” says Dr Brendon Stubss. “The gamification elements – like closing rings, reaching streaks, or competing with friends – trigger reward processing, for example dopamine releases in our brain. They can create a powerful feedback loop where self-monitoring becomes increasingly compelling, and it’s difficult to get off the wheel.”
There was a time when this level of bodily literacy was afforded only to elite athletes. But over the last decade or so, fitness watches have steadily entered the mainstream.
Despite exercising regularly for the last six years, I had, until this year, resisted the temptation to succumb to the smartwatch craze. I felt no desire to know my heart rate – or God forbid, calories burned – on my runs, and the only data I felt I needed in my gym sessions was the weight of the plates. It was only in January, when I began training for the London marathon, and was growing increasingly frustrated with bringing my phone out on my long runs, that I decided that it was worth biting the bullet and seeing what the fuss was about.
And, for the purposes of a marathon, my Garmin proved exceedingly useful. No longer was I forced to pull out my phone to pause Strava at every traffic light, and I did benefit from the insights into my various heart rate zones, particularly during the shorter, stamina-building runs. When I suffered a sudden knee injury a few weeks out from race day, I was able to monitor my cadence to manage the pain and get me over the finish line.
But then, I began to notice the other data points my watch provided. My sleep score, my step count, my body battery, my VO2 max, my HRV (heart rate variability) status – I became fixated on things I had never considered before. And the need to be in a constant state of optimisation became compulsive – I depended on the dopamine hits from meeting the arbitrary and ever-changing targets set by my watch.
In 2007, Wired editors Gary Wolf and Kevin Kelly coined the term “quantified self”, to describe the concept of “self-knowledge through numbers”. Ironically, for me, that self-knowledge also became self-fulfilling – I might wake up feeling refreshed after what I felt was a decent night’s sleep, only for my watch to inform me that, in fact, my sleep score was only 72 and that I’d probably feel exhausted all day. Or I’d be gearing up for a run, and notice that my Garmin’s “training readiness” status was in the red.
“The constant monitoring can lead to excessive self-surveillance and anxiety about numbers rather than overall wellbeing,” says Dr Brendan. “Some users report feeling guilty or anxious when they don't meet their daily goals, which can impact their mental health. While these devices can be powerful tools for health improvement, they can indeed sometimes do more harm than good.”
In 2020, a study that asked university students to report on their experience with their fitness trackers, found that 70 per cent of the students reported engaging in certain compensatory behaviours to reach a step goal while 50 per cent reported doing compensatory behaviours to reach a caloric goal.
The greatest potential for harm is for those with a predisposition for disordered behaviours, who are more susceptible to becoming addicted to their devices and experiencing a relapse of maladaptive habits.
“The detailed tracking of steps, calories, and exercise can feed into existing patterns of control-seeking behaviour,” Dr Brendan says. “What starts as a health tool can transform into an obsessive focus on numbers and metrics, potentially reinforcing or triggering disordered patterns around exercise and eating.”
However, for Dr Joseph Hayes, professor of psychiatry at UCL, it is only those with pre-existing disordered eating behaviours who should be overly concerned about fitness trackers.
“The stats on long-term use of smartwatches would suggest they are not generally addictive: one-third of people use them for less than a year,” he says. “[The problems] are likely to be for only a subset of the population, who probably have other addictive personality traits. It’s a bit like public health programmes for healthy eating or physical activity – in general they are a positive thing for the majority of the population, but for a minority they can be harmful for similar reasons.”
For those who do want to use smart watches in a healthy, balanced manner, Dr Brendan has some tips. “Use them as one tool among many for health monitoring, not as the ultimate authority,” he says. “Set realistic, flexible goals that account for natural daily and weekly variations.”
He also encourages taking regular breaks from tracking, and prioritising how you feel over what your device says.
“The key is to remember that these devices should serve us, not control us,” he says. “They're tools for awareness, not rigid taskmasters.”
