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Heart rate has become unreliable - FR 245 + chest strap

alexrobbo
over 2 years ago

Hi everyone,

I've been using my FR 245 + Garmin HRM chest strap for a while and the recorded HR has been really good but has in the lat week become really unreliable. On a fell run last weekend the HR dropped to an implausibly low rate during a particularly strenuous steep climb (must have been >165 but watch showed it in the 130s. Then when it must have been 150+ it showed 80. I am not certain it was still getting data from the external HRM and not the wrist sensor. I twice stopped the activity on the watch and resumed it which seemed to reconnect to the external HRM and all was good for a while until it fell again. 

connect.garmin.com/.../7355375575

Yesterday while warming up for a run it showed implausibly high HR (165, should have been 120-140). During the run it seemed stuck around 166 and didn't vary with my perceived effort. (166 would be threshold for me but it felt easier. It's possible I was just feeling particularly good). But at 9.0km it completely dropped out then told me "Ext HR connected" but was totally unreliable during the (constant effort) last part of the run: 

https://connect.garmin.com/modern/activity/7380535667

Is this likely to be low HRM battery charge (fairly new unit)? Or something else? 

Thanks!

Alex 

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  • 0 over 2 years ago

    Change the battery. But it could also be the strap degrading

  • 0 over 2 years ago in reply to philipshambrook

    ok I've changed the battery and it has not made any difference. 175 while warming up, then resting rate during high intensity. Annoyingly I couldn't get it to switch to the wrist HR sensor by unsnapping the HRM unit and restarting the activity. 

    One for Garmin support and a warranty replacement I think. 

  • 0 over 2 years ago in reply to alexrobbo
    alexrobbo said:
    Annoyingly I couldn't get it to switch to the wrist HR sensor by unsnapping the HRM unit and restarting the activity. 

    So this is one of the old HRMs with the removable module? I still have one of them in regular use too. As long as the poppers are clean then it's usually been some issue or degradation of the strap that's been the cause. If it's relatively new then chuck the strap in the washing machine as the care instructions on the strap suggest you do every week or so. Fortunately the straps are inexpensive and easy to come by so I'd try one of those first.

    You could also try resetting the sensor by removing the battery, putting it in reversed for a few seconds then fitting it properly.

  • 0 over 2 years ago in reply to philipshambrook

    Good suggestions Philip. I suspect the strap had perished and just needed to be replaced. But I didn't get to find out as Garmin actually replaced the whole unit under warranty.