HR accuracy

What is the general opinion on HR accuracy? During runs, bike rides and just general casual activities? This is my first time with an optical sensor and found the following:

Useless for cycling - somewhat correlated but the F5 missed all peaks
Running seems somewhat ok - poor tracking within the first 5-7 minutes; much better after that. At times regular and optical track extremely well but the F5 is missing a lot of peaks
Average HR on a run has an absolute difference of around 2-3 beats. Not much but the max is off by ten beats
Recovery HR after activities is completely off as compared to my F3 paired with the HRM run. Example: F3 read a 30 beat drop, the F5 recorded a 5 beat drop
Casual activities seem a bit random - one moment my HR is at 45 reading a book, then 70

I have tried various positions on my wrist. Does not seem to make a huge difference. Just want to get a feeling for how much can be expected from the optical sensor.

0 drbignose over 7 years ago

Thanks the posts on this thread. It conforms my decision to use the old HR band from my older garmin device after only my first run.

0 Former Member over 7 years ago

My optical HRM was working really well initially (at least well enough for me to train using HR zones while getting back into running post-recovery), but since using my chest strap on a couple of runs it's significantly off i.e. well below my actual heart rate - by up to 40 bpm. Has anyone else had this problem and/or does anyone know of any possible fixes? This totally diminishes my experience with the Fenix 5s as this was one of my main motivations for getting it.

0 webvan over 7 years ago

OHR has been very unreliable for me on the FR935 since the 5.10 update after working well for months. I tried a hard reset and it seemed to help for a couple of runs but it's give ridiculous values again for the first 5/10 minutes of my runs.

I've wasted enough time as it is being aggravated by that and trying to troubleshoot so I just slap on the red HRM4 now,

0 Former Member over 7 years ago

Hmm... maybe it was the recent upgrade that did it then, which just happened to coincide with using my chest strap...

0 wcsummer over 7 years ago

My Fenix 5X works well when at rest & for easy, short runs. But anything over ~45 mins, or at higher intensity and it seems to hit a ceiling and not register HR above 145. I've worn it with my Fenix 3 and chest strap (both watches set up with exact same profile), ofter seeing the F3 in the 170s but the F5 "stuck" at 145. This doesn't always happen, at times the F5 will show higher HRs. But I can't get close to recording a max HR with the F5.

I've tried wearing it as tight as possible, different positions on my wrist, and changing wrist (and adjusting the setting) but all with the same result. I only bought the F5 because I hate wearing a chest strap. If I could I would return the F5 and continue to use the F3. I do not recommend this watch IF reliable HR measurements are important to you. It is a good watch 90% of the time, but it's the 10% failure when I really need it that is frustrating.

0 Ante over 7 years ago

I did a test yesterday at a high intense group training activity at the gym. Workout with barrel, military press, squats, burpies, all kind of exercises where arms move and potentially shake the watch. On one arm Fenix 5 optical HR on the other my old Vivosmart connected to garmin chest strap. The two watches seldom showed the same bpm, BUT interesting after the workout the showed exactly the same average bpm and almost the same max bpm. Studying details you can see chesty strap give a more "smooth" curve. Conclusions, I was positive surprised i got the same avarage bpm. Im happy with my fenix 5 regarding HR accuracy.

0 Ante over 7 years ago

Did a new test today during a Pulse indoor Cykling /spinning activity at the gym. F5 on the arm followed the chest strap displayed on large screen by +-1 bpm, very satisfied!