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Fenix 6 Pro - Optical HR around 30 bpm higher than HRM strap

Pidge25
over 5 years ago

I have previously used Fenix 3 with chest strap for HR and have just upgraded to Fenix 6 Pro. (4.20, sensor hub 2.60)

The HR reading on the new Fenix 6 is much higher than the strap. I appreciate that the strap is always going to be more accurate, but surely such a large difference can't be right?

At the moment performance/recovery metrics, calories burnt etc are all wrong and stats the vo2max are all being impacted, which is annoying. I spoke to Garmin support yesterday who mentioned that the watch needed to 'learn me' (or words to that effect) and I would see improvements in the readings over the next few weeks. This didn't really make sense to me as surely it should just be much closer immediately and then it might make incremental improvements.

Anyways, I have seen numerous posts about optical HR accuracy, but I wonder if anyone has seen/been able to correct this generally high (by 25-30 bpm) issue?

Cheers

  • 0 over 5 years ago

    So I tried power cycling (turn off/turn on) last night before I ran and then tightened (slightly uncomfortable, but not ridiculously tight) the watch after about a mile (and my heart rate fell back to something a bit more normal), and the run on the left below, seemed to have a heart rate somewhere around normal (125 ish). I was quite happy with this, as it was either a power on/off and/or a tightening of the strap (although it was tighter than I would like to wear it).

    This morning (right hand run), I ran again, with the watch tight, but with no power on/off and annoyingly, despite a slower pace, my heart rate was up to the 150+ mark i.e. too high again...

    Conclusions at the moment are some kind of software bug that necessitates a restart/power on/off of the watch to ensure the HR isn't reading high, combined with very tight watch strap...

  • 0 over 5 years ago

    I don't know what Garmin have done, but this is by far and away the best result I've ever had from WHR when cycling. My scepticism about the utility of WHR is diminishing almost daily. I am hoping for consistency because too often, the next time out the WHR has been hopeless.

    Just in case you don't check the legend in the top right, F6 and Marq on WHR on the wrist, 945 on the handlebars on old version HRM-Run

  • 0 over 5 years ago

    If you are seeing OHR higher by 25-30 bpm, the chief suspect would be "cadence lock", where the watch moves on your wrist, and allows external light to enter the sensor in a rhythmic way with each step, and the watch tends to pick up your cadence rather than your heart rate.

    Wearing the watch band tighter helps prevent movement, and it sounds like you are getting better results from this already. The other thing you can do is to wear the watch band higher on the fleshy part of the wrist, well away from the wrist bone. This helps ensure a better seal against external light entering the sensor.

  • 0 over 5 years ago in reply to mcalista

    Guys, many thanks for the replies.

    I had read about the cadence related issue, but hadn't seen it called "cadence lock", which is a good way to describe it I guess. Based on this theory, I always try and target a cadence of 180+, so it would follow that this level of reading for cadence would drag up the HR readings... I will try the higher placement of the watch, although it feels on the face of it a bit unnatural wearing it higher up!

    @philipshambrook do you know if you have had a recent software update? did you do anything different on your succesful ride?