How Well Do Wearable Activity Monitors Estimate Energy Expenditure?
An interesting study, looking at various wearable devices, wrist, and arm-worn activity monitors, and how well they perform at measuring energy expenditure.
Their findings showed that:
The accuracy in energy expenditure estimates from activity monitors varies depending on the activity.
Larger error is observed from devices employing accelerometry alone; the addition of heart rate sensing improves estimates of energy expenditure in most activities.
In some activity types, research-grade devices are not superior to commercial wearable devices.
Overall, devices demonstrate a significant error relative to criterion measures (established standard measure). These include Garmin, Fitbit, Jawbone, and Bodymedia products. The error of the estimates of mean energy expenditure for these devices is so large that they should not be considered sufficiently accurate. A 10% ‘equivalence/error zone’ has been suggested, and except for the Nike FuelBand, for which three studies reported a mean error <10%, no device consistently met this criterion. The SenseWear Armband Mini was the most accurate device overall but still reported an error ranging from −21.27% to 14.76%.
Different activity types also resulted in errors, i.e. biking versus running versus walking. This may be due to the current algorithms not taking the physical activity type or bodily posture into account. Activity recognition for wearable technology and has been used to improve estimates of energy expenditure, and accelerometers worn on the wrists and thigh can be used to predict activity type. The SenseWear software employs complex pattern-recognition algorithms to determine activity type, which likely contributes to the smaller error observed for the SenseWear Armband Mini in all comparisons.
British Journal of Sports Medicine (BMJ)
O’Driscoll R, Turicchi J, Beaulieu K, et al. How well do activity monitors estimate energy expenditure? A systematic review and meta-analysis of the validity of current technologies. British Journal of Sports Medicine 2020;54:332-340.