Your fitness tracker is (probably) lying to you

We live in a golden age of health tracking. There are apps to track your steps, to input food and drink intake, plan your rise to become fully active from that spot on the couch, and lots more. If you're really serious about it, you can buy an accessory for your phone that helps track a whole bunch of different fitness activities. The inexpensive models can count your steps and tell you how far you've gone, the mid-range models will help you with segment break downs as you run or mile counters as you ride your bike, and the most expensive models are fully waterproof and will track your swimming and all sorts of other things.

Want to know what all of these fitness trackers have in common? They're all liars, because none of them are human-proof and most of them are missing key features to ensure accuracy.

If you're running outside, GPS makes a huge difference

I run 5K every morning by myself, and then my son walks 5K with me right after. Most mornings, I strap on my Fitbit Ionic and my son his Fitbit Ace 2. But occasionally I forget to charge my tracker after a couple of days and just take my phone instead. I have Google Fit, after all, and it's supposed to do live fitness tracking within the app even if I don't have a tracker on my wrist. In theory, this is great because it reduces the barrier to entry for fitness tracking to zero. You already own the phone, so you already have a way to track your activities and push yourself to do more.

Step counting without GPS is a guess, and frequently not a good one.

At the end of my 5K run, the same route I take every single morning, Google Fit said I'd only run a little over two miles instead of the 3.1 miles I know it was. I know this because my Fitbit Ionic is a GPS-enabled fitness tracker, so it gives me a more exact measurement of my movement. There is a way to have Google Fit track your activity with GPS, but I never realized the difference between having it and not was so significant. My phone wasn't the only fitness tracker lying to me that morning; when my son's Fitbit got to the end of the walk, it also said we'd only covered a little over two miles during this active time.

Step counting without GPS is a guess, and frequently not a good one. There's no way for the tracker to know how wide our gait is, because it's different for every person. Instead, you get an average based on the information you've provided. Google Fit asks for my height and weight, so that distance information was assembled based on Google's guess. Fitbit doesn't have any physical information for my son, so it's guessing based on the gait of a child. In both cases, these guesses were way off. There's every chance the same is happening for you, which is why you should have GPS with your fitness tracker.

Eliminating false positives with step counters is impossible

You know that thing you do when you're in a traffic jam and your car hasn't moved in over 25 minutes, so you've just got your music up loud and you're sitting there jamming out an epic drum solo in the driver's seat for everyone around you to enjoy? No? Just me? Fine, whatever.

I'm six minutes into my imaginary drum session, which in case you were wondering sounds way better than my real life drum sessions, and my Apple Watch starts buzzing on my wrist. Congratulations! You've completed your rings! While sitting down, for over an hour, the fitness tracker on my wrist was under the impression I was not only standing up but fully active and doing something worthy of being counted as physical activity. This isn't something exclusive to the Apple Watch by a long shot, my son loves laughing at his Fitbit Ace 2 as we drive, because he can look down and watch as the step count on his wrist climbs as I run over bumps. When he's trying to compete with his sisters to see who has the most activity that day, a 30-minute car ride in some areas is basically a free 800-1000 steps for him.

None of this is to say you shouldn't own a fitness tracker. On balance, your tracker can easily be a force for good in your day-to-day.

Step counters, or pedometers, typically count a single step as the feeling of impact. Old school pedometers had a physical piece that moved up and down, and when that movement happened a step was recorded. Most these days use digital accelerometers, measuring motion and impact from your wrist. But since very little is done to detect and eliminate things that aren't steps, these Total Step numbers or that large ring on the Apple Watch frequently means very little.

The only real solution here is to rely on the data from individual activities. When you tell your watch or your phone to capture a specific kind of activity, it's relying on very specific kinds of motion to give a more accurate representation of your movements. Those events are the most significant indicator of physical activity, especially when paired with a heart rate monitor to apply some additional context to your walk. This way, you're combining steps and environmental movement like vertical inclines with heart rate to paint a picture of how active you are and how that activity has impacted your body.

Fitness trackers are a small part of a bigger picture

None of this is to say you shouldn't own a fitness tracker. On balance, your tracker can easily be a force for good in your day-to-day. For individual things, they can be fantastic ways to see how you improve and give you a better understanding of how healthy you are. But the most popular fitness trackers are marketed as these whole day health monitors, and regardless of manufacturer, I find the notion disingenuous.

Fitbit's 10,000 step a day goal is based on junk science while still being a cool goal to set for yourself. None of these systems include or recommend a rest day after you've done something extremely physical like participate in a triathlon or biked a Century or run a full marathon, which is nuts. Google's "Heart Points" system in the updated Fit app is interesting, but still not something you should use as a health consultant.

Ultimately these things are great individual use tools, often with great extra features like pairing to your phone for calls or receiving notifications, and not really a way to monitor your whole self when it comes to health and wellness. And as long as you pick the right hardware for your needs, fitness trackers can still be a hugely important part of your health journey.

Russell Holly

Russell is a Contributing Editor at Android Central. He's a former server admin who has been using Android since the HTC G1, and quite literally wrote the book on Android tablets. You can usually find him chasing the next tech trend, much to the pain of his wallet. Find him on Facebook and Twitter