SCIENCE SAYS FITNESS TRACKERS DON'T WORK. WEAR ONE ANYWAY

Personal Technology is getting a bad rap these days. It keeps getting more addictive: Notifications keep us glued to our phones. Autoplaying episodes lure us into Netflix binges. Social awareness cues—like the "seen-by" list on Instagram Stories—enslave us to obsessive, ouroboric usage patterns. (Blink twice if you've ever closed Instagram, only to re-open it reflexively.) Our devices, apps, and platforms, experts increasingly warn, have been engineered to capture our attention and ingrain habits that are (it seems self evident) less than healthy.

Unless, that is, you're talking about fitness trackers. For years, the problem with Fitbits, Garmins, Apple Watches, and their ilk has been that they aren't addictive enough. About one third of people who buy fitness trackers stop using them within six months, and more than half eventually abandon them altogether.

As for that guy at work whose Fitbit appears to be bionically integrated with his wrist, it's unclear whether wearing the thing actually makes him more fit. Most studies on the effectiveness of fitness trackers have produced weak or inconclusive findings (blame short investigation windows and small, homogenous sample sizes). In fact, two of the most well-designed studies to date have turned up less than stellar results.

The first, a randomized controlled trial involving 800 test subjects, was conducted between June, 2013 and August, 2014. The results, which were published lastyear in The Lancet Diabetes & Endocrinology, found that, after one year of use, a clip-on activity tracker had no effect on test subjects' overall health and fitness—even when it was combined with a financial incentive. (In a perverse twist, volunteers whose incentives were removed six months into the study fared worse, in the long run, than those who were never offered them at all.) The second, an RCT out of the University of Pittsburgh conducted between October 2010 and October 2012, examined whether combining a weight loss program with a fitness tracker, worn on the upper arm, could help test subjects lose more weight or improve their overall health. The results, published last year in the Journal of the American Medical Association, showed that subjects without fitness trackers lost more weight than their gadget-wearing counterparts—a difference of about eight pounds. And while it's true that weight is not a great proxy for health, the findings also showed that the test subjects with fitness trackers were no more active or fit than those without.

All of which is, frankly, pretty embarrassing for companies that manufacture fitness devices—not to mention disquieting for the people who wear them.

And yet, none of this means you should ditch your fancy new fitness tracker. Have companies like Fitbit and Garmin been slow to incorporate sticky features into their products? Yes. Unequivocally. By 2013—the year Apple brought attention-enslaving push notifications to its phones’ lock screens, and around the time the Lancet study was getting off the ground—fitness trackers and their accompanying apps had only just begun to leverage theories from psychology and behavioral economics. But today's products are different.

The fact is, most existing studies on fitness trackers—including the two I cited above—hinge on devices that are several years old. (Think glorified pedometers that don't connect seamlessly with the supercomputer in your pocket.) And while peer-reviewed research on the latest wave of workout gadgets is still sparse, signs suggest newer wearables are finally becoming more addictive.

For starters, wearable fitness trackers themselves have turned into wildly capable machines. It's no longer enough to measure steps and active minutes; features like sleep-tracking and 24/7 heart rate monitoring have also become table stakes. So, too, have the beefy batteries necessary to make features like continuous heart-rate detection worth a damn. Fitbit's newest "motivating timepiece," the Ionic, can go four days between charges. The Fenix 5, Garmin's flagship fitness watch, can last up to two weeks.

"If it's comfortable, it's waterproof, the display's always readable, and it's got a long battery life, there's less excuse for people to take it off," says Phil McClendon, Garmin's lead product manager. For technology companies, few metrics matter more than engagement. Application developers call it time in app.nging."