Validation of Wearable Devices to Measure Energy Consumption
The Asian Journal of Kinesiology
OBJECTIVES The purpose of this study is to verify how accurately wearable devices measure energy expenditure while walking outdoors. METHODS A total of 20 people, 10 healthy males and 10 females, participated in the study. After approval by the Institutional Review Board of Pusan National University, the experiment was conducted with the consent of the subject. All subjects wore four wearable devices (Fitbit Surge, Android Phone, iPhone, pedometer) and a portable gas analyzer simultaneously and
... walked on flat, downhill and uphill road respectively. All subjects repeated these experiments on each slope three times. The validity was verified through correlation analyses and paired t-test between the energy expenditure measured by the wearable devices and by a portable gas analyzer. RESULTS Under all three road slopes (flat, downhill, uphill road), the energy expenditure as measured by iPhone, Android phones, and pedometer significantly correlated with the portable gas analyzer. However, all three devices were significantly overestimated or underestimated the energy expenditure as compared to the gas analyzer under all three road slopes. Fitbit Surge did not correlate with the gas analyzer for measuring energy expenditure under any conditions, and significantly overestimated energy expenditure. CONCLUSION The validity of energy expenditure measurement during outdoor activities using wearable devices is still low, and more valid motion detection sensors and algorithms need to be developed. Conclusions The most popular wearable devices, such as Android phones, iPhones, Fitbit Surges, and pedometers, do not accurately measure energy expenditure outdoors on flat, downhill and uphill walks.