Overview

• Researchers reviewed 56 studies comparing Apple Watch metrics against gold-standard clinical tools to assess accuracy across multiple device models.
• Heart rate tracking showed a mean absolute error of 4.43 percent and step counting erred by 8.17 percent, both within consumer-grade “excellent” thresholds.
• Energy expenditure estimates averaged a 27.96 percent error rate, far exceeding acceptable margins for reliable calorie tracking.
• Newer Apple Watch models demonstrated gradual improvements in both hardware and algorithms, yielding better accuracy over earlier generations.
• Investigators recommend using the device as a motivational aid rather than a clinical diagnostic tool given its measurement limitations.