Cycling max heart rate

Hi all,

I'm fairly active and reasonably fit. When I swim, run, and paddle my heart rate tops of at ~140bpm. Yesterday I went on a long bike ride and my max heart rate was only ~100bpm.

Has anyone else found this? 


Which BostonSci model ICD/PM do you have?

by crustyg - 2021-08-12 06:18:49

Road cycling (as opposed to mountain-biking) produces very little upper body movement, so there's little to drive the accelerometer, which feeds into the rate-response algorithm to drive up HR.

The Minute Ventilation (MV) in some of BostonSci's PMs (Accolade and Essentio, IIRC) was developed (originally in Belgium) to fix this.  It measures breathing rate and depth of each breath, multiplies the two together =>MV.  I'm not sure if any of the BostonSci ICDs support MV: I shall start investigating. [Edited: it's available in Resonate, Perciva and Momentum and their variants.]

There are folk here who have PMs that don't have MV that have managed to get decent HR increases during road cycling by adjusting their settings.  This may work for you if MV isn't possible.

MaxHR of 140BPM seems a little low for someone of your age, but it may be sensible if you're prone to Vtach.

I feel I should sign myself off as 'Honest Doc.'



by Selwyn - 2021-08-12 08:08:33

Just come back from a vigorous 16 mile cycle. Heart rate (HR) check ( as at present I have atrial flutter) showed a rate of 100 using my Kardia (ECG).

Dancing Samba  was getting my heart rate to 153. ( max. predicted). At present ( with flutter)  even going up stairs quickly gets my HR >100. My ballroom dancing  heart rate exceeds the maximum upper limit set by my PM team. I also have extended my atrial blanking period to get a faster heart rate as prior to this I struggled to get beyond the set upper limit of 115. I was short of breath dancing. Now ( at least prior to my atrial flutter) I am a lot less breathless. 

Cycling on the flat is a problem, as Crustyg suggests, if you want to get a fast HR. I am looking forward to getting back to swimming which does tend to activate the acclerometer in my now rather old fashioned (2009) pacemaker. I have been promised an upgrade to a minute volume+ acclerometer rate response pacemaker next time around. 




by RandomICD - 2021-08-13 17:41:58

Thanks for your comments.
Crustyg thank you particularly for your insight. Mine is a Boston so I will look forward to reading what you find out. I'll also be sure to mention it to the techs at my next checkup.

I do have risk of VTs so they restricted my max hr.

Cycling max heart rate....PM rate adaptation....suppressed upper limit

by darmaggi - 2021-08-13 18:27:34

Hi RandomICD,
I can't speak to any of your specifics since I don't have any details as to which PM/ICD you have, or any programming parameters you've got set, or what cardiac electrical issues you developed that led you to getting a PM/ICD. 
I can tell you I've got a 2nd degree AV blockage Mobitz type 2, that basically created chronotropic incompetence, and exercise induced bradycardia when my HR would drop by 50% precipitously while exercising. I had a Biotronik Eluna 8 DR-T implanted, and it's set on CLS (closed loop stimulation), which bases it's rate adaption off of the electrical impedance of the cardiac muscle. I've had issues with it rate adapting optimally ever since it was implanted 3 years ago, and it was always an issue with it not taking my rate up where it needed to be. I'm also very active, as in highly athletic with my regimen including weight training, long distance cycling and distance open water swimming. We've tried a variety of settings over the years, usually tweaking minor parameters (CLS resting rate control, sensor gain, sensor threshold, rate increase, rate decrease, etc.), and not changing the major programming mode, and up until now I haven't been satisfied.
My issue was, that more often than I would like, it seemed that the PM would get stuck at a suboptimal rate not matching my exertion level in the 80s, 90s, or 100s. It was as if the PM went to sleep....I could go for a 30 mile bike ride and it wouldn't get above 100, but on a good day it would go up to 160 bpm with an average for the ride in the 130s. Until finally, last week, I was at a PM clinic with a Biotronik tech I hadn't seen before, so I explained my history of complaints thoroughly, and all the different attempts to correct the issue. She came back with a new idea for some changes, that she wasn't willing to enact until she got a hold of my cardiac EP, which she did that day and made the changes, and I haven't had an issue with a suppressed rate ever since. It's been most profound when I'm swimming, because trying to swim in the ocean with a rate that won't go above 90 bpm is like swimming through pudding, but now it easily tachs up to 140 or 150 and I feel like superman. So, the change she made was to my Auto PVARP setting, which she turned off, and shortened the [ms] delay from 375 to 225. PVARP is post ventricular atrial refratory period which is the delay between cycles, and there is also a blanking period when the PM won't sense the ventricle if it just paced the atrium. I think they normally program the Auto PVARP in a specific way because most techs are worried about pacemaker mediated tachycardia(pacing at an inappropriately fast rate) when your exertion level doesn't warrant it. The bottom line is I think we finally found the silver bullet programming issue that I knew had to be at the bottom of my dissatisfaction with my PM's ability to rate adapt properly. I'm so glad I don't have to do 5-10 minutes of calisthenics before I jump in the ocean to try and get my HR elevated to a point above 100 so I'd be able to swim in a fashion I'm used to and know my fitness level has no problem supporting.
Again, I have no idea what kind of PM you have, but it can't hurt to bring up the issue of the Auto PVARP setting the next time you go in for a follow up, or PM clinic with your manufacturer's tech. I'm fairly certain this is a adjustable parameter common to all pacemakers, no matter the manufacturer, or programming mode you might be set to.
Good luck, and let me know if this information is of any help....and let us know if and when you find a solution for your rate adaptation problem.

Thanks @darmaggi!

by ar_vin - 2021-08-13 21:09:12


Thanks for a very detailed post of your Biotronik experiences, your persistence and your success in getting your PM settings dialed to your activities!

Please do take a few moments to complete your profile so other members may better understand your diagnosis, exact PM model, geographic location etc.

Posts like yours could be life changing to other member struggling with similar issues!


Thanks darmaggi, and updated profile.

by RandomICD - 2021-08-14 08:12:11

Thank you for the detail darmagg! This is also really useful. I never knew it was all so device specific.

I have updated my profile to the model I have. Does anyone know what the abilities of this device is? 

Also, what would one expect my heart rate to be for my age? My brady will obviously impact this but it would be useful to have a benchmark, even if only academically as this would help my understanding of my energy levels during exercise.

I was expecting a model name or model number - *not* serial number

by crustyg - 2021-08-14 09:02:56

Something like Resonate/Perciva/Charisma/Vigilant/Momentum or any one of a bunch of D numbers D520/D432/D320 etc.  You get the picture.  You will have this information on the little card that they gave you which you very occasionally need to show when a hand-held security wand beeps at an airport, or stadium (obviously not Wembley, we all know that there's no security there...).

I have already updated my earlier comment at the top of this thread, providing the information that you need.

Defib info

by RandomICD - 2021-08-14 09:14:58

Hi crustyg,

The info I provided was that on my card. I didn't include the serial number.

I can't decode that

by crustyg - 2021-08-15 05:00:45

Sadly, as I explained, the exact model name or number isn't in the updated information on your profile.  If you ask your EP-doc for the most recent settings report from your device, that will have all of the information required.

Best wishes.

You know you're wired when...

You always run anti-virus software.

Member Quotes

Do feel free to contact the manufacturer of your device. I have found them to be quite helpful when I have had questions and concerns.