Like all heart rate tracking technologies, accuracy is affected by physiology, the location of the device, and different movements.
When the sensor is placed on the forehead, the heart rate may not be accurate if the headband snugly fits. Either too tight or loose may result in a poor signal. Using the proper rubber band size is essential for generating the report. If the larger one is too loose and the smaller one is too tight, making one or two knots of the larger one works.
Besides, muscle movements like frowns may also affect the sensor's skin contact.
December 14, 2022 — FlowtimeTeam