The appeal of fitness-tracking smartwatches is that they have all the answers. They turn our squishy bodies’ inscrutable secrets into hard numbers we can plainly read and analyze. But we would be fooling ourselves if we believed that our smartwatches always tell the truth. According to a new scientific analysis, not only do wearables often get things wrong, it may not be possible to ever really know how accurate they are.
This isn’t going to be shocking news to longtime Lifehacker readers. We’ve discussed the fact that some smartwatch metrics are more reliable than others, and that calorie burn is one of the less accurate ones. On the other hand, heart rate variability shows different raw numbers from one device to another, but the major recovery-focused devices all manage to capture the same rough trend—if you trust my homebrew study with a sample size of one.
So what do we know about the accuracy of the smartwatches on the market, and why is it so hard to answer that question? That’s the problem that the recent analysis, from a group of sports scientists and data scientists in Ireland, set out to answer. It’s an umbrella review—a study of studies of studies—that aimed to collect all the relevant published data on consumer wearables.
I suppose, much like taking most vitamins, trackers can make us feel better about ourselves. It’s not to say they are useless, but they are not medical grade accuracy, and as I posted recently, there is also no absolute “maximum heart rate that works for everyone. So it is better to use these to keep track of changes, and look out for signs when you maybe need to go visit a doctor.
Steve Jobs would have been” right as well about especially wrist based trackers, as a lot depends on how you wear it. Too loose, too low on the wrist, etc can make a massive difference.
And also very true that models get replaced so quickly with new one’s, and good testing takes time to get done.
See https://lifehacker.com/health/how-accurate-fitness-tracker