Abbey Sharp used to check in to the dashboard of her Fitbit daily, measuring her progress against her peers. “I’m competitive. I’m the kind of person this was designed for,” says the registered dietician and food blogger. For a year, she kept upping her daily step goal by walking more and running longer on the treadmill. The recommended 10,000 was a cinch, so she tried 15,000, then 20,000. “I was getting shin splints because I was pushing myself for too long,” she says.
But she wasn’t pushing herself in other ways. With all that jogging, she had less time for strength-building exercises like yoga and lifting. One of the warning signs was a body-composition test at her gym. “I’d actually lost muscle mass,” she recalls. When her device went kaput, she didn’t buy another.
While health trackers such as Fitbits have helped many lose weight, exercise more or hit the sack earlier, they’re not working for everyone. The hype over activity trackers has worn off, exposing some of the issues with technology-driven fitness regimes.
Last year, the Journal of the American Medical Association published a study that followed almost 500 participants trying to lose weight, about a third of whom were given an activity tracker. Those who wore trackers lost an average of 3.6 percent of their weight after two years — compared to the 6.4 percent average of those who didn’t wear trackers. Many other small studies have been positive, however.
One reason a health tracker might hinder rather than help is that it can encourage cardio-heavy routines, as it did for Sharp. Tracking weightlifting requires manual entry, and the dashboard screen prioritizes steps and kilometres, so wearers might let strength training slide. That’s a problem, says Gregg Parris, a personal trainer and lifestyle coach in Toronto, given that strength building is “the biggest bang for your buck when it comes to weight loss.”
Then there’s the false security that seeing a high step count can bring. “Someone might have done 10,000 steps a day without realizing it,” he says. “Now they see the number, and they think, ‘I can reward myself,’” says Parris. Research shows that people overestimate how much they should eat after exercising, and that diets dictate weight loss far more than exercise.
A burger-type reward can be especially dangerous when you consider that “calories burned” can be notoriously wrong on wearables. A 2014 study found they were off by anywhere from 10 percent to 23 percent, depending on the tracking device. Other studies have shown that Fitbits and other trackers don’t always correctly measure heart rate as well as non-step activities like cycling.
For Sharp, the “breakup” with her Fitbit came down to a more fundamental issue. She was listening to her device, not her body. When her Fitbit told her she’d hit her step goal, she’d think, “I don’t need to do anything else today,” even when she had the energy for, say, a yoga class.
The experiment did, however, make Sharp more mindful about how long she was sitting over the course of a day. And Parris points out that the social sharing aspect of Fitbit can be highly motivating. So you can wear that tracker – just don’t go on autopilot.