Comparison of consumer-grade wearable devices with a research-grade instrument for measuring physical activity in a free-living setting

Step counts were largely consistent with the ActiGraph for most devices; however, the Fitbit showed a notable overestimation. However, the ability of those devices to accurately measure MVPA and PAEE appeared to be more limited, particularly at higher activity levels. These findings underscore that the selection of a consumer-grade wearable for research or clinical use must be carefully guided by the specific metric of interest. However, the findings for the Oura Ring should be interpreted with caution due to the small sample size.