What's the sampling rate of Fitbit Charge 3 during training session, off-training and sleep? Fitbit seems not like to disclose it but others like Whoop and Biostrap (slightly) does : r/fitbit
Fitbit Charge 3 Fitness Activity Tracker, Graphite/Black, one Size (no fitbit Warranty Support), 0.06 Pound (Renewed) - Walmart.com