Validity of Wearable Trackers for Measuring Steps, Energy Expenditure and Heart Rate in Korean Elderly

PURPOSE: This study aimed to assess the validity of a physical activity tracking device by comparing physical activity data from older adults, including the number of steps, energy expenditure, and heart rate (HR), with data obtained from research accelerometers, wearable watches, and mobile apps.METHODS: A total of 24 healthy older adults (aged 65-79 years) wore a wearable tracking device and used a respiratory gas analyzer while walking and running on a treadmill at speeds of 3.8 km/h, 4.8 km/h, 5.6 km/h, 6.4 km/h, and 8.0 km/h, in a randomized order. This study evaluated seven wearable devices: one research accelerometer (ActiGraph GT3X+), five smartwatches/fitness trackers (Samsung Galaxy Watch Active 2, Fitbit Versa 2, Xiaomi Mi Band 4, Garmin Forerunner 945, and Apple Watch Series 2), and one mobile application. Step counts were measured directly, HR was compared using a Polar H7 HR Sensor, and energy expenditure was assessed using a Quarkb2 respiratory gas analyzer.RESULTS: Commercial wearable watches and mobile applications were more accurate than research-grade accelerometers for monitoring steps during walking and running in older adults. HR measurements from wearable watches were more accurate than those from reference devices. Although energy expenditure measurements from mobile applications and wearable watches were less accurate than measurements of steps and HRs their accuracy was comparable to that of research-grade accelerometers.CONCLUSIONS: This study provides insights into the strengths of using wearable devices in healthcare and fitness fields, which seek to monitor and actively manage the physical activity of older adults using wearable trackers.