So some background on my use with the HR built into my fenix 5x, training for a marathon I foound a lot of really weird anomalies using it.
For example, running my dogs at a Z2 pace, I would see averages in the 160-170bpm. Then I could go do a tempo run and see averages around 120bpm. Neither result where I expected. Yes, I tried every possible way of wearing the watch to get the results I should expect. Some days it seemed correct, more often then not, it was useless.
I moved to a chest strap for training last year and felt it was always correct with what the level of effort was. Great, except I don’t always wear it.
Which leads me to yesterday… mountain bike ride, Z2 effort. I mount my watch on my handle bar now with the Garmin bar mount. No chest strap. Start riding and the watch is reading a pulse🤔. It’s reading around 90-120… not far from where I would expect it, except I had nothing on me to detect it with.
Is the wrist based system “guessing” at my HR? How much can one take from HR data if the data is made up?