A study by scientists at the University of Mississippi found that Apple Watch accurately tracks heart rate and step count, but is off by nearly 30% in calculating calories burned. That level of inaccuracy, according to the study’s authors, makes this parameter unsuitable for real-world energy expenditure.
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The Apple Watch remains one of the most popular wearable health tracking devices. Researchers analyzed data from 56 scientific papers on its effectiveness compared to clinical standards and found that it had an error rate of just 4.43% in heart rate and 8.17% in step counting. These figures are considered to be within the acceptable margin of error for consumer gadgets.
At the same time, the error in calculating the energy burned was on average 27.96%, that is, more than three times higher than the acceptable level. This inaccuracy was observed regardless of the Apple Watch model or the type of physical activity of the user. Eric Shaff, one of the authors of the study, emphasized that wearable devices are useful as a motivational tool, but not all indicators should be taken as truth. This is especially true for calorie data. “They are best used as a guideline, not as medical data,” the study notes.
Similar results have been previously demonstrated by other independent studies, pointing to a systemic problem in consumer fitness gadgets. At the same time, it is noted that the accuracy of devices improves every year. For example, Apple, constantly working on improving algorithms, achieves increasingly accurate readings, although it does not position watches as medical devices. The company continues to add new health-related features and improve existing ones, including body temperature monitoring and sleep apnea detection.
The researchers stressed that their goal is not to discredit wearables, but to highlight their current limitations. According to Jennifer Ross, a co-author of the study, such data helps developers improve the technology, making the devices more useful for both regular users and medical professionals.