Another HR accuracy observation

I run at a consistent pace, and my VO2 max runs around 45. The graphs that show average heart rate, max heart rate, pace, and so on over time are pretty flat.

Running at my normal pace my HR will get up to 145 -150, and my time in Zone 4 (80% to 90%) is about 30% of the run.

I ran for about a year with a Fenix 5, then about a year with a FR945. Same consistent results.

Last summer I changed to a Fenix 6, and things continue as normal until about 4 weeks ago, when my HR would be 10 BPM higher than usual, despite running at the same pace and feeling normal. I was spending twice as much time in Z4, and my VO2 dropped to 40 over several weeks. My status was unproductive and overreaching, and I was logging way more intensity minutes than before.

Today I went for a run with the F5 to see if the issue is the F6 HR accuracy after firmware 5.0, as I've ready plenty of people report this.

Sure enough, with the F5, my HR was back to normal - mid 140s instead of over 150.

This is all with the same HR strap. That's pretty annoying if I logged 4 weeks of crap data. I'm going to stay with the F5 until I read about something changing with the F5 HR. Makes it a waste of money for now.

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0 mcalista over 5 years ago

Actually, this is worth highlighting, as the OP is talking about differences using a chest strap, rather than using the OHR.

What would be interesting would be to record he same run on the Fenix 5 and the Fenix 6 from a single chest strap. This would eliminate this issue of measurement, and show that something weird is happenning in terms of how the watch is recording that data.

0 phoglund_ over 5 years ago in reply to mcalista

No problem at all for me with 5x and 6x connected to the same Polar H10 with ant and they match my H7 perfectly connected to v800.

https://analyze.dcrainmaker.com/#/public/889c86e6-286a-4fd7-664a-0a6fe07a338f

https://analyze.dcrainmaker.com/#/public/d27f1f97-effa-495e-5c43-fc81b3c3d4d1

(6x red v5.0 ,5x orange v15.1 both HrmH10, v800 green HrmH7,

other sensors, see setname, GPS config, see comments if there is any)

0 crt_hun over 5 years ago in reply to mcalista

If you have a Garmin HRM-Tri/HRM-Run strap, there is a way to compare the strap and the OHR measurements on the same watch without 3rd party app. At the end you will have 2 identical activities, the only difference is the HR data.

This is an example in my case:

0 Dr Phil over 5 years ago

My apologies to the OP. I overlooked that this was HR strap related.

In which case you really might need to talk to Garmin.

Are the heart rate zones set the same? Yes, I accept that does not change the measurements detected but it might help with the VO2max calculations.

You will be able to run with both the F6 and the F5 connected to the same strap at the same time. You can directly compare the recorded .fit files with a number of programs such as DCR Rainmakers online app - Analyzer/. I'd be happy to do that for you if there isn't a trial version.

0 DCeremuga over 5 years ago in reply to Dr Phil

Phil, what makes this interesting is that I had the exact same problem, which was the last straw for me and I got off the Fenix bandwagon. Even with an external strap, the Fenix was giving random data that made no sense for my HR. It was like it was flipping back and forth from the OHR to the strap. Nothing was accurate.

Something really wonky going on.

0 Dr Phil over 5 years ago

I've just recorded this run with a 5+ and a 6 Sapphire connected (ANT+) to the same strap an HRM-Run with the removable module. Nothing to tell really between the heart rate recordings.I know one swallow doesn't mean it's summer so I'll record another couple of these over the coming days. It is something you can do too and I'm happy to pop the files into the analyser for you if you're happy to share the files with me.

0 Dr Phil over 5 years ago in reply to DCeremuga

That's really unfortunate and nothing I've seen when using a strap, except when the battery's going flat. Hard to suggest changing the battery in the OP's case as it is the same strap being used. However, there is always the possibility that the battery might be a little weak and the F6 might need a stronger signal. I know, sketchy thinking but Occam's razor and all that.

0 Tangmu over 5 years ago in reply to Dr Phil

I'll try changing the battery in the HRM-TRI. Also based on a post above I'm going to put something under the F6 so the optical heart rate can't provide data.

0 Tangmu over 5 years ago in reply to Dr Phil

HR zones are the same on each. I'll try wearing both at the same time. Heck, I still have the FR945. Maybe I'll do all three.

0 Dr Phil over 5 years ago in reply to Tangmu

Probably easier just to turn off the wrist heart rate in Sensors and Accessories. Make sure you do the test with and without OHR active. FWIW, my test was with OHR still enabled.