How Accurate are Fitness Trackers?

Fitbit, Apple Watch, Whoop and Garmin. Chances are, you wear one or have a friend who does.

These fitness wearables can track your steps, sleep, calories, heart rate and even detect heart irregularities.

With all of these amazing features, it’s no surprise that millions of people wear them each day and are worth a pretty penny.

But how accurate are these wearables? Let’s take a look!

“The short answer is: It depends,” Assistant Professor of Kinesiology and Epidemiology at the University of Wisconsin-Madison, Lisa Cadmus-Bertram reports. “The long answer is that they are accurate enough to be useful for most people for most purposes. But it also varies by what it is you’re trying to measure.”

In essence, the features could be accurate enough to motivate you to exercise and move each day, but should not be taken as the gold standard.

Step Count

If we look at counting steps, this is probably the most accurate feature of all wearables however it does come with its share of limitations. For those with an altered gait pattern, or walk very slowly, wearables tend to underestimate the step count.

It also appears that the wrist is the most inaccurate position for the wearable, because it will detect certain movements of the hand, not just when walking. Research shows that the hip is the most effective place to detect steps.

Heart Rate and Rhythm

Research shows that heart rate detection can to be quite accurate during rest, however less accurate during more intense exercise.

If you are completing a marathon, a chest strap and heart rate monitor would be the way to go, but for the general population a wearable can give you a general idea.

It is also important to remember that they are ‘consistently inconsistent’, so you will start get a general trend of your heart rate over a period of time.

If we look at the new ECG feature on the Apple Watch, these aren’t as accurate as a 12-lead ECG in hospital (obviously), but can still offer some insight. For somebody with a heart condition, just be aware of its limitations.

Burning Calories

The least accurate feature of all.

To determine calories burnt over a day, the watch assumes many different factors such as: weight, height, gender, age, muscle mass and fat mass. It cannot take into account other factors such as food consumed, hormone function, stress, sleep, and weight fluctuations.

In saying that, it doesn’t mean this function is useless. Despite its inaccuracy, the fitness tracker may still play a part in motivating someone to hit a certain calorie goal for the day and remain active.

To Summarise

Despite its inaccuracy, fitness trackers certainly have their place in the health and fitness world. A fitness tracker can provide daily motivation, ‘game-ify’ step count and increase exercise intensity and intent. If we understand that the tracking features are not the gold standard, they can certainly help us achieve our goals!