In this Study of the Week, Chris dives into “Accuracy in Wrist-Worn, Sensor-Based Measurements of Heart Rate and Energy Expenditure in a Diverse Cohort” https://pubmed.ncbi.nlm.nih.gov/28538708/ The ultimate takeaways? Fitness trackers are very accurate in some measurements, and wildly inaccurate in others. As with everything, it should simply be another tool in your toolbox, not something that dictates anything to you.
