Comparison of physical activity and sedentary time measured with the ActiGraph GT3X-BT and Actical accelerometers

Accurate and ongoing assessments of physical activity (PA) and sedentary time (SED) are needed to support public health surveillance, evaluate interventions, and advance the understanding of how movement behaviours relate to health. After six cycles of data collection (2007 to 2019) using the Actical (AC) accelerometer, the Canadian Health Measures Survey (CHMS) transitioned to the ActiGraph wGT3X-BT (AG). The AC and AG accelerometers differ technically and mechanically in how they measure movement behaviour outcomes such as SED, light PA, moderate-to-vigorous PA, and step counts. This study compares AC and AG accelerometer estimates of these movement behaviour outcomes, to determine whether these data are comparable across CHMS cycles.