How accurate is your fitness tracker?

Table of Content

Table of Content

These days, fitness tracker is no longer a bizarre term comparing to the late 20th century when it first appeared.  From a newbie of fitness to an experienced athlete, fitness tracker is seen as a knowledgeable companion, which contributes to make clear the fitness journey that they did enter. It definitely takes you a bunch of time researching the best fit tracker on the ground of your demand.

However, in terms of accuracy, there is another question: can I believe all the data after the tracker recorded my activities? Ironically, this is an absurd question. Unless people believe in the accuracy of a tracker, in what case do fitness trackers become more and more popular under a numerous brand names?

Here are some additional figures of unexpected inaccuracy among typical brands. Lowa State University researchers did a test on 60 volunteers (30 males and 30 females). They had to wear 8 different fitness monitors in a 69-minutes workout while performing 13 different activity, such as typing, playing tennis, running, etc. This is the results: The BodyMedia FIT device was the most accurate and comparable to research models, with a 9.3-percent error rating. After that came the Fitbit Zip (10.1 percent), Fitbit One (10.4), Jawbone Up (12.2) Actigraph (12.6), Directlife (12.8), Nike Fuel Band (13.0), and Basis Band (23.5).

Just put aside what you have read and start finding the root of the problem. A plenty of researches suggested that displayed data might experience a slight disparity because of some reasons, mostly based on the monitor that the tracker is working with. Let’s find out the host factors affecting the trackers’ accuracy and 3 ways to restrict the state of inaccuracy.

Types of monitors

There are generally 2 types of monitor: accelerometers and heart rate monitors.

Accelerometer-based monitor

Accelerometers record the changes in motions, such as up-down, side to side, front to back, which are relative to the device. The software algorithms analyze these motion and count the steps that you have taken, then estimate how many calories you have burned and give data of how active you are in general. Remember that activity trackers also record your rest time – the period when you have been sitting around. Some well-known brand names using accelerometers include NikeFuel Bands, FitBug, Jawbone, etc. Accelerometer-based tracker just calibrates for step count and cannot tell much when you are cycling. Besides, this function cannot clearly understand the differences among your exercises. In this case, find an app that can perform those tasks for you, then sync the data to your smart phone. Tada!


Fitbit stands out to be useful during specific activities, like running and walking. As some researches revealed, Fitbit either underestimate or overestimate energy expenditure by 1 – 25 calories. This number varies gradually when you take more intense exercise.

Heart rate monitor

This is a favorite amongst athletes to use heart rate monitors as a means to keep track of their intensity levels during workout and their recovery as well. Unlike accelerometer-based monitors, heart rate monitors use equations based on users’ age, gender, physical activity level and resting heart rate to give the number of calories you burnt. However when it comes to heart rate monitoring function, the more intense exercise that you do, the little less precise the data is.

Mathew Lee, an exercise physiologist and professor at San Francisco State University, said “at a higher intensities of exercise, it went off a little bit, but it was still reasonable. As the technology continues to get better and better, it is just going to get more and more accurate.”


For the greatest accuracy, your tracker should be worn against the wrist, just above the wrist bone. The preciseness varies from person to person, mostly based on the size of their arm. For instance, a device may not fit as well with thinner arms. Less contact with the skin results in minor incorrection. Clinton Brawner, a clinical exercise physiologist at Henry Ford Hospital in Detroit recommends checking the pulse by counting the beats for approximately 15 seconds, then multiplying the number by four. You now have your data, then comparing it with your tracker to check whether there are any differences.

Heart-rate monitor is a great tool to ensure that you are reaching your expected intensity during your HIIT workout. Some specified monitors allow users to aid their own heart rate zones, and thanks to this personalized zones, it might result in more effective training sessions.


In general, no matter what algorithms is running your tracker, this device do pretty good job at recording a person’s overall activity level every day. The mode of exercise is the host of factor affecting the data collected. Although your fitness tracker may not be able to give the exact data, it can be still useful. Having a closer look at how it counts your steps, you will be amazingly surprised by the precise number it represents. This can be a means of motivation, which reminds you to sit less and move a little more. Any movement, even household chores, can be beneficial to physical activities.

Handful tips to make your fitness tracker more accurate

  • When deciding the tracker you are supposed to afford, add your personal information to the “criteria list”, including your age, gender, height and weight. These data help to estimate more accurately the number of the calorie you burn, the steps you take and the distance you travel.
  • Never unknot your tracker under most circumstances, except from charging. Make sure to wear it at the same position during your workout process.
  • When using heart rate monitors, be aware of caffeine or any kind of simulator because these substances may drastically affect your heart rate. A normal action of drinking a cup of coffee before working out (or during rest time) can easily affect monitor readings.
  • It may be a cliché but check out some reviews of previous users and compare the functionalities of the chosen trackers whenever you are staggering. The best fitness tracker is definitely out there for you.

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