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.

Top Replies

All Replies

0 Tangmu over 5 years ago in reply to Dr Phil

Dr Phil said:
Is all the four weeks data bad or just some of it? If it’s only some of it it is possible you had some underlying issue or your training might have changed?

Yes, 4 weeks of higher HR on every ride and run with over a year of data to compare, then my normal HR with 2 runs and one ride after switching back to the F5. All using HRM-TRI, no optical. My step rate and pace were the same as always, just the HR was higher. Bike rides vary, so I wouldn't be quick to attribute higher HR to the watch on rides, but my running is very consistent. My HR only gets higher if I speed up.

I lost 5 points on VO2 max in that time, after over a year of varying a point or two up and down, and of course plenty of stats to look at that says my workout load, intensity, pace, etc. didn't change, just the HR shot up. My status is back to Productive, beginning after switching back to the F5 and getting typical HR.

If I was sick or something it sure matched up well with which watch I used. Yeah, I'll keep them both on for now, in case I see abnormal data again.

0 Dr Phil over 5 years ago in reply to mcalista

Definitely strange. And no battery changes in the strap during/after that period? Any washing of the strap that you did perhaps? I throw mine in the washing machine about once a week when I'm wearing it but I know some people don't.

Sorry I can't be more helpful other than t suggest a couple more sessions with both then perhaps alternate with the same session repeated individually.