Research: Wearables, including the Apple Watch, are poor at tracking calories

In a paper published in January this year, researchers try to evaluate the usefulness of smart devices worn on the wrist for monitoring energy expenditure and heart rate. Apple Watch Series 6, Polar Vantage V, and Fitbit Sense were used by 30 healthy male and female participants engaged in weight training, cycling, running, walking and even sitting. As reference devices, the team used the Polar H10 chest strap and the MetaMax 3B.

Now, we won’t bore you with the details of the study or the methods used as they look pretty solid and talk about the results instead. The boys of Stronger by science summarized in a simple table that evaluates the accuracy, variability and reliability of each device.

As it turns out, all of the devices were pretty poor at tracking calories in almost any activity. Not only that, but the average deviation from actual daily spending was unpredictable and varied wildly, making clocks useless in tracking calories. This is because you can’t reliably track progress even if absolute values ​​are turned off. It appears that wearables are even more inconsistent with individuals having below-average and above-average energy expenditure.

The research also appears to be in line with previous ones attempting to evaluate the same capabilities but with different wrist-worn devices.

The good news is that the Apple Watch Series 6 was quite reliable at tracking heart rate in all activities. Polar Vantage V and Fitbit Sense wearables vary by exercise. The step count also appears to be perfect for all devices involved in the search.

The bottom line? Despite its limitations, such as the small sample size of devices and individuals, research appears to be in line with previous ones suggesting that commercially available smartwatches and wrist-worn fitness trackers do not provide reliable measurements of daily energy expenditure. Furthermore, they are highly unpredictable.

However, heart rate monitoring and step counting are usually quite useful and reliable functions. In fact, some research suggests that smart wearables alone can have a positive impact on one’s fitness life. People who use smart wearables tend to increase overall activity and step count.