The researchers found that most wrist-worn devices could measure heart rate accurately; however, the calories burned had a considerable error. Regardless of the brand, the devices were 20% off their predicted calories on average
This article examines the accuracy of Smart Band Watches and other Fitness Trackers in measuring calories burned, specifically focusing on their reliability as calorie counting devices and wrist-worn devices. The goal is to thoroughly explore the realm of health and fitness technology and provide detailed insights into the concerns surrounding these popular devices
HOW ACCURATE ARE SMART BAND WATCHES FOR MEASURING CALORIES BURNED SUMMARY
- Regardless of the brand, the devices were 20% off their predicted calories on average.
- Apple was the best of all the watches examined, and Samsung Gear 2 was the worst.
- As a general rule, don’t rely on wristwatches to accurately measure calories burned if you use them for weight loss purposes.
Today, every new wristwatch has an integrated fitness component that allows users to track heart rate, metabolism, etc. You may feel some sense of pride looking down and seeing that your wristwatch said you burned 800 calories after your workout, but how accurate are these devices? A new study was released in the Journal of Personalized Medicine with some eye awakening results.
SMART BAND WATCHES FOR MEASURING CALORIES BURNED STUDY
The Stanford research team measured fitness trackers accuracy of heart rate and calories burned and Wrist-Worn Devices Accuracy eight devices: Apple Watch; Basis Peak; ePulse2; Fitbit Surge; Microsoft Band; MIO Alpha 2; PulseOn; and Samsung Gear S2. The researchers compared the heart rate against ECG and gas exchange indirect calorimetry (FDA-approved equipment for measuring calories burned). The subjects were tested in a wide variety of settings, such as sitting at rest, walking, running, and cycling.
The researchers found that most wrist-worn devices could measure heart rate accurately; however, the calories burned had a considerable error. Regardless of the brand, smart band watches accuracy were 20% off their predicted calories on average. Median error rates across tasks varied from 27.4% for the Fitbit Surge to 92.6% for the PulseOn.
To calculate calories burned accurately, walking (31.8%) and running (31.0%) tasks demonstrated the lowest relative error rates across devices, while sitting tasks exhibited the highest at 52.4%. Among the watches examined, Apple outperformed the rest, securing the top spot, whereas Samsung Gear 2 lagged behind as the least accurate.(1) Earlier studies have revealed discrepancies in calories burned estimates, with variations reaching up to 43% compared to the reference standard.(2) The devices displayed a range of error from -266.7 to 65.7 kcals. Both Apple and Polar watches have been identified to overestimate calories burned, with overestimations by 58% and 69%, respectively.
Fitbit devices overestimated calories burned by 39.5% of the time and underestimated calories burned by 48.4% of the time.(3) As a general rule, don’t rely on wristwatches to accurately measure calories burned if you use them for weight loss purposes. They generally have an error rate of 20% or greater. If your watch says that you burned 500 calories, it’s at least 100 calories less or more, depending on the brand.
1. Shcherbina A, Mattsson CM, Waggott D, Salisbury H, Christle JW, Hastie T, et al. Accuracy in Wrist-Worn, Sensor-Based Measurements of Heart Rate and Energy Expenditure in a Diverse Cohort. J Pers Med. 2017;7(2).
2. Wallen MP, Gomersall SR, Keating SE, Wisløff U, Coombes JS. Accuracy of Heart Rate Watches: Implications for Weight Management. PLoS One. 2016;11(5):e0154420.
3. Fuller D, Colwell E, Low J, Orychock K, Tobin MA, Simango B, et al. Reliability and Validity of Commercially Available Wearable Devices for Measuring Steps, Energy Expenditure, and Heart Rate: Systematic Review. JMIR mHealth and uHealth. 2020;8(9):e18694-e.