phone as accurate as a fitbit

Study says: Don’t buy a fitness tracker, just use your phone

Pretty much every fitness tracker on the market does the same thing: Using an accelerometer, it tracks how many steps you’ve taken, and from that accelerometer data, usually can extrapolate distance traveled as well as calories burned. Of course, your smartphone has an accelerometer, so why do you need a Fitbit, or a Jawbone Up 24, or a Misfit Shine? According to a new research letter published in the Journal of the American Medical Association, you don’t — smartphones can track steps just as well as a dedicated fitness tracker.

The study looked at 10 different trackers — four smartphone apps and six fitness trackers, including the Moves app (now owned by Facebook) for iOS and Android, multiple Fitbit models and the Nike Fuelband. The researchers — some of whom are still medical students — strapped several trackers to the subjects, who then walked on a treadmill for 500 steps, and then 1,500 steps, twice. Ultimately, the 14 participants in the study ran 56 trials (four treadmill runs each) meaning that there were 560 gadget step-reading data points.

The study found that phones, either running the Moves app, Fitbit app, or the Health Mate app, were as accurate as the dedicated step tracking hardware, and most of the trackers were within 10 percent of each other — except for the now almost-discontinued Nike Fuelband, which recorded steps that were over 20 percent lower than the observed steps and other devices.

One interesting tidbit from the study: In eight of the 560 device trials, the gadget wasn’t properly configured to record steps, which lines up with my personal experience that your step tracker will not be working around one percent of the time. There’s also a chance that the study’s findings could be affected by configuration settings — for instance, Fitbit’s option to tell it that you’re wearing it on your dominant wrist.

This study’s not going to be the be-all and end-all for step tracking accuracy. In fact, this study observing 10 women and four men recruited at a college isn’t all that different from certain anecdotal evidence, like this informal experiment conducted last year by science journalist Rachel Feltman. In my experience, most wearable tracker manufacturers know there’s a roughly 10 percent difference between various step readings, which is more than accurate enough for early adopters and techies. But this study underscores the fact that as wearable devices and step trackers infiltrate the healthcare system, more academic research will be required.

12 Responses to “Study says: Don’t buy a fitness tracker, just use your phone”

  1. soumava

    From my understanding and online research, it’s pretty obvious that a pedometer has to be put in your jeans pockets or on your belt for accuracy. Wearing it on your wrist will track your hand movements, and that is very different among individuals and not likely to be configurable. Also, it’s very difficult to “wear” your phone on your wrist for accurate sleep tracking.

    For heart rate monitoring without a chest strap, tight contact with skin where capillaries are closer to the skin is highly recommended. No fashionable/fancy smart-watches provide that kind of grip, it’s much better to use a Mio or Scosche band for dedicated continuous pulse monitoring.

    You’ll sacrifice a lot on accuracy if you want a one-size-fits-all device for monitoring everything.

  2. Mike JOnes

    That isn’t entirely true. Phone can’t capture metrics like cadence, range of motion for running and cycling accurately. Also you can’t swim with your phone.

    However, for fitness wearables, Moov is the best wearable I’ve used for exercising compared to other wearables. It motivates you with a coach unlike the other wearables. It’s multiple sports which includes running, cycling, boxing, swimming, and body weight programs.

    Here’s the homepage since I didn’t see it above

  3. Yeah, that’s an idea. I’ll just start wearing my phone in the shower, take it swimming with me, like my Misfit can do. Heck, I really don’t obsessively check my phone enough, I think I should NEVER EVER PART WITH IT, making this a really viable plan!

    Duh. This is why we have wearables, so my clunky big phone can sit on the counter or whatever.

    Lots of flaws in this “helpful” article. But you go, team.

  4. Tom Raftery

    One problem with using your phone to track your walking is that it only works while in your pocket. Walk with your phone out in your hand, reading GigaOm articles, Tweeting, or whatever, and your steps are not counted.

  5. This assumes you are only using the fitness tracker for measuring steps. The one I have measures sleep and has an alarm that can wake you at the most advantageous time in your sleep cycle.

  6. Who wants a bulky phone swinging in their pocket while jogging? Phones don’t come built built in heart rate monitors, either. Wrist trackers have their limitations, too though. For example they won’t count steps when pushing a shopping cart because your arm isn’t swinging. I wonder in the future if the jawbone/fitbit/3rd party apps will use both phone and wrist straps counts and somehow reconcile the differences between the two. They both have their uses.

  7. Do you remember those combos that came with a small Black and White TV, radio, cassette player, clock, and perhaps some other things all in a nice portable “package”, well, you got a so-so quality TV, so-so radio and so-so cassette player. The dedicated health tracker has definitely its advantages IMO, and while perhaps not for everybody, the use of the Smartphone as a health track device is also not for everybody either.

  8. Josh Hoffman

    This is assuming that you are always going to pick up your phone every time you getup to move. So when you are walking around your house or office to count your steps are you plugging in an extension cord to ensure you are getting all your steps counted while you charge the phone? Are you strapping the phone to you while you sleep to see what your waking patterns are for?

    While a phone will work for some, there are reasons and advantages of a dedicated tracker. As someone with sleep apnea I like being able to see the night I wake more or am restless to help me figure out what I’m doing or not doing that correlates to my restlessness

    • Eric Benedetti

      This is exactly right, I don’t own any of the fitness trackers, but there are reasons you’d want to use one instead of your phone. Smartphones are large and when someone is out exercising they usually don’t carry their phones. It’s just easier to have a wrist-wearable fitness tracker in those situations. Plus a lot of women keep their phones in their purse and not on them at all times so there are many points during every day where they would be unable to track those steps. The fitness trackers you wear on your wrist are mostly for convenience, certainly not a necessity in most cases.

  9. Nicholas Paredes

    I have been conducting research in fitness tracking and have found major inaccuracies in the trackers. Oddly enough, some people do use more than one. They rarely provide the same information. Personally, I have found my phone to be more than sufficient. The problem is in tracking micro movements, particularly in the work place. Standing, sitting, walking indoors…

    Yes I will be getting an Apple Watch. It will be interesting to see how accurate they are. I’m certain Apple has seen the same issues.