As fitness tech gets smarter, gadgets like Garmin, Fitbit, WHOOP and Apple Watches have become little health coaches on our wrists. They promise to keep an eye on our health metrics, including how many calories we burn. But how precise are they when it comes to calorie tracking?
What Wearables Promise
These devices have skyrocketed in popularity because they offer a peek into our daily health and fitness habits. They track everything from our steps and heart rates to how well we sleep and the calories we burn.
But Are They Accurate?
Despite all the tech packed into these watches, they might not always hit the mark with calorie counts. Here’s why:
1. One-Size-Fits-All Algorithms
Most of these gadgets use basic formulas that consider things like age, weight, height, and gender. Sure, these details are important, but they don’t capture everything about someone’s metabolism or body composition. Everyone’s metabolism is unique, shaped by factors like genetics and muscle mass. Wearables often don’t account for these personal quirks, which can vary a lot even among people who look similar.
2. Sensor or Hardware Shortcomings
The sensors are meant to guess how intense your activities are based on your movements and heart rate. But they can get it wrong sometimes. If your watch isn’t strapped on correctly, for instance, the heart rate sensor might miss the mark, messing up the calorie count.
What Research Says
Studies, including a notable one from Stanford University in 2017, reveal that while wearables are pretty good at measuring heart rate, they’re not always so hot when it comes to calories. The errors in calorie tracking can range from 20% to a whopping 93%.
My Own Experience with Myself and Clients
In my own experience for cardio based activities, if you assume 80% to 90% of what is tracked is probably correct, you will roughly be OK. For gym based activities, I find they can sometimes confuse rest between sets as exercise, which can lead to some overestimation of your calorie burn at times.
For clients who cycle or run, and they want to maintain their weight for example, we will look to eat back 80% of the calorie figure from the device at first. The scale when they weigh themselves will then tell us if we need to increase or decrease this over time – as long as food is being tracked accurately as well.
Using a heart rate strap around your chest, along with your device, seems to make them more accurate, but you don’t have to use one.
So, should I use a tracker?
I use an Apple Watch and a Garmin Cycling Computer with a Heart Rate Monitor, and they are incredibly useful tools that I use most days to monitor calories and other useful training metrics.
As I often say to clients, sometimes being “consistently inconsistent” is enough if you are using the same baseline measure or device each time. For example, if you went for a run today and you burnt 200 more calories than yesterday, whether the calorie figure is 100% accurate or not, you still know you worked harder.
Again, if you weigh yourself often, the scale will help you work out how accurate your device is – especially if you are tracking your food as well.
So, while wearables like Garmin and Apple Watches might not offer 100% accuracy in calorie tracking, they still offer real value. These gadgets provide a rough estimate of calories burned, which can be particularly helpful still for maintaining an awareness of your activity levels throughout the day for either weight loss, sports performance, or for fuelling training.
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