I can't believe I'm typing this having ditched a Vivoactive 3 because the sensor hub crashing but it appears that after a week of solid performance it appears my F5's hub has just crashed, doing cardio at around 160bpm and the HR monitor just plunged down to 90 and stopped there for a couple of minutes, could it be the F5 is prone to the same sensor hub crash?
Static rowing machine, no change in arm elevation, dropout occurred during a steady 35 reps per min then climbed back rapidly towards the end of the set. Oddly, there is a sensor hub crash file in the F5 debug folder, dated 18 april 18 ( I got the watch new from John lewis last week)
I'm not convinced this is a defect or crash in the sensor hub.
Rather, the wrist flexing and movement associated with the rowing motion makes it tough for a wrist-based OHR sensor to accurately pick up your pulse.
You could try wearing the watch higher on your arm, well away from the wrist bone. This gives it a larger blood supply to measure, and is less prone to movement.
Alternatively, try a chest strap, or something like a Sosche Rhythm (OHR sensor worn on the upper arm)
Try to look to hidden folder in the root of your fenix... there is a log file with all the list of sensor activities.... mine has a lot of error during night ... my OHR is prone to loose data for hours during the night.... even if the clock is well fitted to the wrist
