Heart Rate Monitors

I am an active cyclist and hiker w/ a pacemaker.  Recently, my Polar HR10 has been giving very strange readings.  It works for a while normally and then strats giving low rates, below 50 (which I know cannot be true).  Changing the battery does not seem to help.  I have purchased an Apple Watch 6, which is supposed to be accurate but is it?

Does anyone have any idea what could be wrong with the Polar strap?  Does anyone have any solid info on which is the more accurate method for measuring HR?

It is really important for me to monitor my HR as I am trying to get my PM optimized and dialed into my style of excercise.


Thanks for any info on both topics



Heart rate monitors

by AgentX86 - 2021-04-06 16:50:44

None of this stuff is accurate.  Anything with a pulse-ox type of sensor (the LED shining though the skin) is almost useless.  It works when it works but gives wild answers when it doesn't.  Which is it now?

The ECG style of sensor is easily confused by our pacemaker and will also give wild answers.  You may find one model that works and some don't have issues at all.  Evidently you're not so lucy.  They don't work for me at all either.  Counting your pulse manually is the only reliable method, though a little diffcult while riding.

There is also the possibility that you're having an arrhythmia that's confusing the HR monitors.  These usually show a low HR, often lower than the PM's minimum setting.   It's a half-truthful reading but not very useful.

Heart rate

by djg2020 - 2021-04-06 18:07:29

I have a Apple watch 6 and a pulse oxymeter. I have compared heart rate readings at the same time on the same hand. I did this many times and the Apple watch was always 4 to 6 beats higher than the oxymeter. Also with O2 level, the watch was always higher. I need to take both with me next time I see my dr and compare them with hospital devices.

heart rate monitors with light sources

by quikjraw - 2021-04-07 04:24:33

I have been using heart rate monitors for years, I was fitted with a pacemaker in November 2020.

All of my heart rate monitors have been electrical based chest straps and they are very accurate and realiable for what they are, UNTIL I had my pacemaker when they simply stopped working.

The visual light heart rate watches and now straps are not quite as good but they are certainly not useless. If you want to buy one the best place to look up their performance is by googling "dcrainmaker". He does the most in depth reviews of all devices and you will see that he tests the performance of the heart rate sensing accuracy and reliability and some are very good indeed. In fact some are now designed to work during swimming.

The good thing about the light based sensors is that they do not care if you have a pacemaker or not as they are simply seeing the flow of blood in your veins when your heart beats.

There is one thing to be aware of though, heart rate sensors tell you your heart rate (beats per minute) almost instantaneously whereas checking your pulse is telling you your average heart rate over a minute or however long you count. These are slightly different things neither are wrong.

Garmin, Polar and Sunnto are the best brands for accuracy.



by Tracey_E - 2021-04-07 09:21:17

I've never been able to get a Polar to work with a pacer. The most accurate for me is the apple watch. It's not 100% but it's reasonably accurate, accurate enough to tell trends.

The best way to optimize the pacer isn't with a hrm but with a Holter and/or stress test. My ep regularly uses both on active patients to fine tune the settings. 


by airwayotto - 2021-04-07 12:22:51

Thank you all for your comments.  Quite a diversity of opinion but helpful, nonetheless


Polar H10

by ar_vin - 2021-04-07 13:29:34

To the OP:

Looking at your post history you seem to have had the H10 for a few years now.

Did the H10 ever work for you or did it stop working recently?

Did anything else change?

I use a Polar H10 to track all my workouts and I it works perfectly for me. My activities are hiking, running and indoor weight training. I've had very poor results with wrist worn (or armband) optical HR monitors - they don't work well for running or even hiking for me. 

I have a Medtronic PM for SSS and chronotropic incompetence; I'm paced almost exclusively in the RA. It took me a while to get the settings adjusted (with a lot of help from forum members). After the settings were dialed in, I'm back to my usual running/hiking activities at the same level as I was prior to my being diagnosed with SSS. Recently I've been biking a fair bit and I find I struggle up big long uphill stretches but it's entirely likely I'm not in great biking shape (yet).




More on Polar

by airwayotto - 2021-04-12 17:50:21

I used the HR10 for a few years and it seemed to work fine.  However, I recently had a atrial flutter that resulted in some wierd heart rates and consequently some changes were made to my PM settings while I wait for an ablation.  Now, the HR chest strap gives very low readings that do not make sense.  I bought an Apple watch 6 and it seems to work fine.  


I am also  currently struggling getting up hills where I did not struggle before and something seems amiss.  However my plan is to wait until after the ablation before dealing with that as there are simply too many variables.

I just find it very odd that the HR strap  no longer works (I've changed batteries twice).

switch to a forearm HRM worked for me

by ak - 2021-04-14 01:39:53

i recently switched the the polar verity sense forearm HRM and it works well , i have also used the scotshe rhythm and also have good experience. the key for optical hrm is that they need to be planted flush and not move to much other wise readins are very misleading. i think the chest strap suffers from the same issue 

polar verity sense

by xassantex - 2021-05-06 12:33:36

i have a Garmin Fenix 3 and bought the Garmin strap a couple of months ago. It doesn't work well. 

So i purchased a Polar Verity Sense  2 weeks ago and must say i'm quite happy with it. I wear it on my right arm and it's a lot more comfy thatn those friggin straps . I sed the latter for many years and hated them . 


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My eight year old son had a pacemaker since he was 6 months old. He does very well, plays soccer, baseball, and rides his bike. I am so glad he is not ashamed of his pacemaker. He will proudly show his "battery" to anyone.