How Accurate Are Fitness Trackers? by Grace Griffin

How Accurate Are Fitness Trackers?


With gyms being closed and our daily routines have changed, we’re all questioning a little more if we're being active enough. If you’re anything like me I’ve been paying a lot more attention to my activity on my Apple Watch and really trying to close all my rings! But each day when I look at the number of calories I’ve burned, my steps, and stand time I get a little suspicious. Just how accurate are fitness trackers?


Before really diving into comparing fitness trackers and their accuracy, it’s important to understand how they work. Most fitness trackers like the Apple Watch, FitBit, and Whoop have both accelerometers, which measure your body’s acceleration to estimate energy expenditure, and heart rate monitors, which use equations based upon age, height, gender, weight and activity level to estimate energy expenditure. Most trackers also include GPS and gyroscope to help keep track of your distance and if you’re sitting or standing. So then how accurate are each of the components and is it even worth it to wear them?


Overall, most fitness trackers do a decent job of measuring what they should, but they’re definitely not perfect, especially when it comes to measuring calories. One Stanford University study found that even the most accurate fitness trackers are off by 27% with caloric estimates. The same study found that overall most devices, especially the Apple Watch do pretty well at measuring heart rate. There’s a ton of research being conducted right now on fitness trackers and as technology improves then hopefully so will their accuracy.


Fitness trackers do a great job at helping remind us and encourage users to move more which is always a good thing, but we all need to be aware of how well they work and not rely on them too strictly.



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