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.
  • Former Member
    0 Former Member over 8 years ago
    For casual activity it seems to be quite bad currently. My Fitbit Charge 2 appears to be more accurate. One of the reasons for this is that the Garmin optical HR recognition is much more sensitive to vibrations due to train/car rides etc. Also, the watch needs to be worn significantly tighter than the Fitbit to give a usable heartrate reading. I will hopefully make a more rigorous test using an auxiliary chest monitor throughout the day.
  • For casual activity it seems to be quite bad currently. My Fitbit Charge 2 appears to be more accurate. One of the reasons for this is that the Garmin optical HR recognition is much more sensitive to vibrations due to train/car rides etc. Also, the watch needs to be worn significantly tighter than the Fitbit to give a usable heartrate reading. I will hopefully make a more rigorous test using an auxiliary chest monitor throughout the day.


    I wore my Fenix 5 while mowing the lawn today and even started an activity to see if there were any drops in HR tracking since it way quite bumpy and there were lots of vibrations from the lawn mower. Below you can find a link to a short video I made while mowing, the HR graph from GC and an attempt to show how loose I wore the Fenix (I can easily fit one finger between the watch and my wrist).

    https://streamable.com/h7yjr
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    All in all I am very pleased since there were no drops at all, although I can't say anything about the accuracy (which also doesn't look too bad though).

    You do have to keep in mind that optical HR tracking can be a bit of a hit and miss for different people though (skin color, how tight you have to wear the watch, left or right arm, inside or outside wrist etc.).
  • Former Member
    0 Former Member over 8 years ago
    Heartrate recordings comparision


    First picture:
    Garmin HRM vs Scosche (paired with 910xt on right wrist)

    Red: Scosche
    Blue: Garmin HRM




    Second picture:
    F5-OHR vs Scosche

    Blue: F5-OHR
    Red: Scosche

    Absolutely perfect!
  • Here's a summary of the "general consensus".
    This ties is with my observations across a range of optical HRM devices from a number of brands as well - so it's not specific to just the F5.

    For running it is "good enough". Any running activity where you a trying to run intervals or hit a lot of hills it will sometimes lag behind. I've never seen anyone complain about the dreaded "cadence lock" with the Fenix devices but I've experienced it in the past with Fitbit/Tomtom and the Forerunner 235.

    All wrist based OHRMs are iffy for cycling because your wrist flexes a lot while holding the handle-bars which throws the optical sensor off.

    You run into similar issues with any sort of activity that either requires rapid changes in heart-rate (interval training, HiiT training etc) or anything where your arms are heavily involved (weights, cross-fit, callisthenics etc).

    The all day heart rate is really only useful as a guideline to what your resting heart-rate is on a day to day basis and what your overall average is for the day. It might be wildly off in the odd moments that you check it, but it should get a good read each day on how you're tracking.

    For myself personally - I use a chest strap HRM for most activities because of it's accuracy, but I'm happy to use the OHRM for those times when I've misplaced my chest monitor.
    But I use the optical readings for the resting heart rate/day to day trend information. That's where it is of most use to me.
  • What heart rate monitors do y'all recommend?

    I have an older garmin hrm, but with it I got a series of drops in my Body Combat class. From the pattern, I really think it was that my arm got too far away from the chest strap during punches... even though my arms aren't THAT long. How much range should this watch have, anyway?


    I decided to purchase the rhythm scosche, but that band can't keep up with Body Combat. The first time, I was getting ratings of 208 beats a minute, and the second time the darn thing froze up. I'm not sure why it was blinking red most of the time either. When I walked with it the day before, the light on the scosche stayed blue.
  • What heart rate monitors do y'all recommend?

    I have an older garmin hrm, but with it I got a series of drops in my Body Combat class. From the pattern, I really think it was that my arm got too far away from the chest strap during punches... even though my arms aren't THAT long. How much range should this watch have, anyway?


    I decided to purchase the rhythm scosche, but that band can't keep up with Body Combat. The first time, I was getting ratings of 208 beats a minute, and the second time the darn thing froze up. I'm not sure why it was blinking red most of the time either. When I walked with it the day before, the light on the scosche stayed blue.


    I've used both a Wahoo TICKR RUN and the newer Garming HRM4-Run and I've never had any major issues with any exercise I do. This includes box-fit classes.
    Ant+ shouldn't have any issues with the distance. Did you try any of my other suggestions from your original thread before buying the Scosche?
  • I've used both a Wahoo TICKR RUN and the newer Garming HRM4-Run and I've never had any major issues with any exercise I do. This includes box-fit classes.
    Ant+ shouldn't have any issues with the distance. Did you try any of my other suggestions from your original thread before buying the Scosche?


    Heh,
    I didn't consider, from the reviews, that the scosche would have the same problems as the wrist based ones because of position. But on third thought of that, why wouldn't it?

    I do have some old polar straps. I'll see if they will work with my garmin hrm.

    Ancient Polar hrms (the unit itself) are not bluetooth, correct?

    My F5s definitely drops to 70 when it loses connection.
  • oHR will indeed work well for running PROVIDED it's not too cold as that restricts the blood flow to the hands and prevents it from working properly in my experience. When it's warm it will even do a decent job on intervals, although there might be some delay for the first fast one.

    In terms of good straps, I've had more than I care to remember and thought I'd found the "best of breed" with the Viiiiva but I've found that during long sessions on hot days it can end up losing the plot, regardless of the strap I've mated it with (polar, 4iiii, garmin, etc...). I've recently upgraded to the "all in one" HRM-Run (red frame) and so far so good.
  • I see varying results.

    In the activity below, however, the FR935 optical sensor very closely matched F5X+HRM-Run during a run in the hilly Greenwich park, which I found to be incredibly impressive:

    Fenix 5X and FR935- both watches were set to every second recording, GPS+GLONASS and worn on my left arm;
    This is my usual Tuesday morning run in Greenwich park.

    Fenix 5X setup- HRM-Run+Stryd, watch calibrated to an altitude of 10m at the start;
    FR935 setup- optical HR only, watch calibrated to an altitude of 10m at the start;

    http://www.mygpsfiles.com/app/#yt1PXMoM
    Note: altitude data was excellent; the optical HR sensor tracked extremely well with both Max HR and average HR having the exact same values; as a result the calories expended have the same value!

    Garmin Connect links:
    F5X: https://connect.garmin.com/modern/activity/1657340784
    FR935: https://connect.garmin.com/modern/activity/1657340846

    Stryd PowerCenter link:
    https://www.stryd.com/powercenter/run/6227828964065280
  • Former Member
    0 Former Member over 8 years ago
    Today I did some (3x) 5min "cruising intervalls". After #2 and #3 I made a short walk break.

    Blue: F5 OHR
    Red: Garmin HRM

    You can see that the HRM strap needed some time at the beginning to get proper values.
    During the last two cruising parts the OHR lost connection. After the intervalls the heart rate was not spot on but acceptable again.



    edit: FYI today was very cold. I missed my running gloves!