A new study evaluating the accuracy of Apple Watch sensors found that while the device excels at measuring heart rate and step counts, its calorie expenditure estimates can be significantly off. The research, conducted by a team from the University of Mississippi, analyzed data from 56 studies comparing Apple Watch readings against clinical-grade monitoring tools.
The results showed strong performance in heart rate monitoring (4.43% error rate) and step counting (8.17% error rate). However, calorie burn calculations averaged a substantial 28% discrepancy across various activities including walking, running, cycling, and mixed-intensity workouts. This pattern persisted regardless of user age, health status, or watch model.
Experts Recommend Cautious Interpretation
Lead researcher Dr. Minsoo Kang acknowledged the device’s utility despite its limitations. “These wearables are excellent for tracking habits and motivating physical activity,” he told Eureka Alert. “However, users shouldn’t treat every metric as medical-grade data, particularly calorie estimates.”
The study noted progressive accuracy improvements in newer Apple Watch models. Doctoral researcher Ju-Pil Choe observed consistent technological refinements across generations, though cautioned that updates represent incremental rather than revolutionary changes.
Apple has not publicly commented on the findings. Industry analysts suggest the research may prompt wearable manufacturers to enhance energy expenditure algorithms while reinforcing the importance of understanding device limitations.
