Chances are pretty good that you own one. And if you don't, look around and you will see them everywhere. What I am referring to are those stylish little gadgets of various different brands that call themselves "fitness trackers". These devices, such as Fitbit, Jawbone and Garmin versions claim to record daily steps, calories burned, heart rate and even sleep patterns of its users. Many of my clients own them and boast about how many steps they have gotten that day or inversely complain that they haven't hit their daily goal of burned calories. I actually had one myself for about 6 months until I chose to stop using it. Why? Because I discovered on my own that it was significantly inaccurate. For example, pretty much every time I went on a run it was over a mile off on my distance. Sure it didn't know my exact stride length, but I feel that over a mile is quite a big error of margin.

Now let me first start off with a few points about why trackers can be helpful in certain ways. If these devices help to prompt behavior and activity in general, particularly if it is more than without it, then it is doing one of its intended jobs. The accountability factor is definitely worth noting, as it is nudging the user to move more, and maybe eat more healthfully. So this is a good thing!

However, unfortunately, and in my opinion more importantly, the fact that these "helpers" can be significantly inaccurate is not only frustrating but could be downright dangerous. Let me cite some examples to explain why:

• Currently Fitbit is facing a lawsuit alleging that its heart rate monitoring technology is inaccurate. One participant in the suit had her trainer test her heart rate to be 160 bpm, while her Fitbit recorded 82 bpm. So, if one was truly relying on the Fitbit heart rate, it would be perceived as not working that hard at all, which could entice the user to push to levels above safe zones. This is scary!!
• A study out of Iowa State found the calories burned were inaccurate ranging from 9.3 to a whopping 40 percent! This could lead people to think they burned a lot more calories than in reality and could give "permission" to consume more calories than they should.
• Certain activities such as resistance training are hard for the device to "record" since you may be exercising quite vigorously without taking many steps. Conversely, certain movements such as typing can be recorded as steps since most of these devices are worn on the wrist. Both scenarios lend to inaccurate steps/calories burned.
• If one "truly" wants to measure their heart rate, distance, and a good estimation of calories burned he/she should wear a real heart rate monitor with a GPS system. Not everyone is interested in such great detail, but I assure you that this is a much more accurate form of information (i.e. NOT a mile off).

One article I read states "Consumers generally let fitness tracker makers off the hook by setting low expectations for these devices. This likely corresponds with our willingness to stash them in a drawer after mere weeks or months of use." Therefore the tracker makers have collected our money without much improvement of their inaccurate products.

In summary, if you use a fitness tracker and have had a good experience, have seen results, and feel it motivates you to keep active/eat better/sleep more, then great. However, if you have a fitness tracker and hang your hat on every number it spits out at you then, BEWARE!