Fitness trackers, either worn on the wrist or enclosed in your phone, are ubiquitous. They are pushed as essential for measuring individual activity, almost always expressed as “steps” over the course of the day. Striving to be healthy is great, but are fitness trackers actually dangerous? And how accurate or useful are they really?
The Problem with Accuracy
It’s been 10 years since the first tracker, the FitBit, was released. Currently, one in four people wears one, tracking at least part of their habits daily.
The goal for most fitness tracking devices is to hit 10,000 steps per day. That’s easier to attain in Manhattan, a walking city, and a bit harder in rural areas or a city like Los Angeles where a car is essential on most days. In those cases, reaching that step goal might mean an additional trip to the gym.
Unfortunately, most fitness trackers aren’t even accurate about those crucial step measurements.
In 2016, a reporter at CNBC wore 10 different trackers at once. He then worked out and compared the step totals on each. They varied by quite a lot; up to 20% in some cases, which will seriously throw off your step count. The heart rate monitoring varied as well, with most devices undershooting the rate. For distance, it was the same story. Accuracy, in this completely unscientific study sample of one man, was out the window.
In a much more academic example, a 2017 Stanford study published in the Journal of Personalized Medicine ran 60 people through their workout paces while wearing various fitness trackers. They were measured while sitting, walking, running, and biking, looking at heart rate (HR) and energy expenditure (EE). The accuracy was best for the biking, and worst for, ironically, walking.
“In conclusion, most wrist-worn devices adequately measure HR in laboratory-based activities, but poorly estimate EE, suggesting caution in the use of EE measurements as part of health improvement programs,” the study states.
Fitness Trackers: An Expert Opinion
Researcher Daniel Epstein, assistant professor of Informatics at UC Irvine, has made tracking devices a specialty. He admits they’re problematic.
“Though fitness trackers have been getting better, accuracy is an issue for a couple of reasons. The biggest is people want credit for the activity they do. A tracker which misses activity can’t help people keep a record, get badges or other rewards, or compete with their friends,” Epstein tells Parentology.
And, if the tracker is inaccurate for some activities, that could end up driving workouts.
“Another challenge is people often change their exercise to match what a tracker can record accurately, such as giving up on swimming because only walking or running is supported by their tracker,” Epstein says. “This is problematic for a number of reasons, such as people changing their exercise to work fewer different parts of their body.”
Thus, if you’re looking for a fitness tracker to give you totally accurate step and calorie counts, you might be out of luck. It’ll give you a ballpark figure, but if you’re a meticulous person, the lack of accuracy will be frustrating. This is where fitness trackers can prove dangerous to some people.
The Problem with Obsessives & Fitness Trackers
In writer and humorist David Sedaris’s latest essay collection, Calypso, he writes about his FitBit. In the essay “Stepping Out,” he documents his introduction to the tracker and his escalation from 10,000 steps per day to over 65,000. As a sober alcoholic and an obsessive personality, his healthy habit spiraled into self-destruction. It took him around nine hours per day of walking, listening to podcasts and cleaning up trash on the British roadways.
“At the end of my first 65,000-step day, I staggered home with my flashlight knowing that now I’d advance to 65,000 and that there’d be no end to it until my feet snapped off at the ankles,” Sedaris writes. “Then it’d just be my jagged bones stabbing into the soft ground. Why is it some people can manage a thing like a Fitbit, while others go off the rails and allow it to rule, and perhaps even ruin, their lives?”
Humor aside, the idea of fitness addiction is pretty dark. The most dedicated of athletes can actually be harboring rather dangerous, self-destructive tendencies.
In a 2018 study in Research in Sports Medicine called Ultra-Obligatory Running Among Ultramarathon Runners, researchers discovered exercise addiction overrides common sense.
“Despite a high health orientation, most ultramarathon runners would not stop running if they learned it was bad for their health as it appears to serve their psychological and personal achievement motivations and their task orientation such that they must perceive enhanced benefits that are worth retaining at the risk of their health,” the study authors write.
Add on a fitness tracker to already obsessive exercise tendencies, like that of people with eating disorders, and it’s a recipe for disaster. In 2017, an Eating Behaviors study entitled Calorie Counting and Fitness Tracking Technology: Associations with Eating Disorder Symptomatology concluded that:
“Individuals who reported using calorie trackers manifested higher levels of eating concern and dietary restraint, controlling for BMI. Additionally, fitness tracking was uniquely associated with ED symptomatology after adjusting for gender and bingeing and purging behavior within the past month. Findings highlight associations between use of calorie and fitness trackers and eating disorder symptomatology. Although preliminary, overall results suggest that for some individuals, these devices might do more harm than good.”
If you have a child looking to get more fit with who also struggles to fit in, you might want to think twice before either getting her a fitness tracker or encouraging her to use one. If she does have one, it’s important to monitor their use and talk to them frequently about self-image and why they’re using these trackers.
Fitness Trackers Don’t Just Track Fitness
These trackers don’t just track steps. Some will monitor your sleep (mostly through auditory feedback). The Sleep Number bed even has a built-in sleep monitor.
Of course, if you can be overly obsessive and neurotic about tracking your steps, you can also become obsessive about sleep stats. It’s enough to drive one to insomnia, and in some cases it actually does. Sleep specialists are now noticing an uptick in patients who have self-diagnosed nonexistent sleep disorders, all by following, believing, and perhaps misinterpreting their sleep tracker feature. Sleeplessness caused by data overload now has its own term: orthosomnia.
Some new trackers will also track your blood pressure. That might seem like a great idea for people with hypertension, except that it might trigger what’s called “white coat syndrome,” where the medical presence actually creates stress which — bingo! — raises blood pressure. That’s not a favorable outcome.
Do You Really Need the Approval of a Machine?
We’ve all caught ourselves talking back to Alexa or cursing Siri. While AI isn’t quite perfect, it’s getting pretty close to feeling kind of human. The problem is when these devices and technologies, intended to make our lives easier, interfere with actual benefits.
Listen to the siren call of your fitness tracker, hurt yourself by walking too far and too long, like Sedaris did, and soon you’ll be visiting a podiatrist and not walking at all. On top of the potential for overuse and abuse, there’s also the idea of having to answer to one more entity. A tracker, if taken too seriously, becomes a taskmaster.