Heart Rate Irregularities during cycling

As a cycle coach, I have been monitoring my heart rate to power response regularly and have noticed that my heart rate acts extremely oddly during my rides.

This is best seen on an indoor trainer, where I can control all the parameters.

During the zone 2 main section of the training, 30 minutes to 75 minutes the power (and speed remained constant). My Heart Rate was a constant 110 bpm at 160 watts for almost the full duration of the 45 minute block. However, for no reason at all, with power remaining at 160 watts, my Heart Rate increases dramatically to 140 bpm, only dropping to 95 bpm after I reduced my power output to 100 watts. The initial increase was accompanied by tightness in the chest before the Heart Rate increase and heavy breathing too. 

I have told my treating physician about the regular occurrence of this feature in my cycling. My Heart Rate parameters are set at 35 (lower limit) and 160 (upper limit). He tells me that this is due to the limitations of modern pacemakers and they are prone to 'glitches' as they are not designed for people exercising in the way I do. 

However, this is a very easy session (zone 2) and yet the pacemaker is still not able to adjust appropriately - I would understand more if I was working at very high intensities.

I find it hard to believe that pacemaker technology is still not able to deal with proper pacing, especially with all I have read about the advanced technology employed. 

Is there something that can be changed on the pacemaker settings as, now my physician has told me there is nothing more he can do and my next appointment is in a year's time in July 2025.

Many thanks

Phil


8 Comments

HR Info after Pacemaker Implant

by JHCOON - 2024-07-27 17:17:22

Hi Phil...

I am 70 and was a cyclist for 20 years. I quit after nearly being killed twice by people in cars texting. All that cycling turned me into an info-hungry fanatic and I track everything. I use an Apple watch Ultra and have compared the HR results with the watch with a Polar H10 chest-strap monitor. I am new to the Pacemaker world - it was my Apple Watch that detected my low heart rate when I decided to wear it just to check out the sleep tracking function. I showed the results to my neighbor who is a retired ER doc and he told me to go immediately to the local ER. Long story short - I had a pacemaker installed the next day. If I hadn't gone that day I guess my wife would have been selling my slippers on Craigslist. Anyway - after the pacemaker implant I can't get a viable HR reading from any device I've tried. The tech at my last "device check" said the pacemaker "interferes with HR monitors and you will likely not get a good reading anymore". This is a bummer since I am now experiencing shortness of breath when I do HIIT or do any rucking. (I used to walk with 25lbs of lead in a backpack) I would love to hear others experiences. Sorry for writing War and Peace

JHCOON and PHILMTB

by piglet22 - 2024-07-28 07:10:39

Hello

I'm with you on cycling experiences.

I've been forced off the road by a coach only to end up in a rubbish filled verge, had handlebars hit by a vehicle and had several facial fractures.

Result, stopped cycling as an exercise as just too dangerous and now walk instead. Cycle tracks where they exist (UK) are in poor condition.

I'm of the opinion that fitness trackers and the like are at best indicators, but even if not clinically accurate, are still very useful.

When I asked my GP about heartrate monitors, she recommended the chest strap type.

My advice to anyone with a pacemaker would be to have something to keep an eye on what's happening. My go-to measurements are BP monitor, oximeter and two fingers on radial pulse.

Pacemakers can certainly fool clinical ECGs at first glance and if left to interpretive software, can give rise to some alarming indications like damage from previous heart attacks where there haven't been.

Pacemakers themselves can be fooled by ectopic beats and lead to symptoms similar to those you had the pacemaker fitted for in the first place. I've experienced it at first hand.

The pulse oximeter seems to get itself in a right state if it picks up arrhythmias, but in normal conditions, it's quite good. I suspect that there's some signal conditioning going on like averaging that has a job to keep up with changing pulse rates.

Though not really practical for training, the BP monitor copes quite well with complications.

I'm rather hoping that my next device due soon will allow me to see far more information via Bluetooth.

25 pounds sounds like my shopping bag sometimes which I often lug 3 or 4 miles.

How much work is your pacemaker doing

by Runsalot - 2024-07-28 08:17:29

My pacemaker was implanted at the beginning of April to help with av block 2. Set at 50 low and 170 high with a response rate at 4 out of 5. Since April I have been rebuilding my fitness and recently completed in several sprint triathlons. I have not noticed anything unusual with my heart rate (I monitor with a garmin chest strap while biking and running). Most of my training since building back is zone 2 (80 to 90%). Recently I have been pushing a bit harder to get back my race fitness, especially on the bike and run.

I haven't had my three month check up yet, but my guess is my atrial may be functioning well for the most part and not needing to be paced often. My ventricles are now keeping up because of the pacing....I don't experience the skipped beats like I used to which allows me to recover better while sleeping.

Reading your question, I don't get a sense how much your atrials are being paced and how much is natural pacing and if you have a response rate setting to keep both your atrial/ventricle aligned.

I am no where near an expert but those are the things I would investigate.

Your heart is smart....

by sgmfish - 2024-07-29 19:07:15

The body has many ways (e.g., CO2 levels) of detecting what one's heart needs to do to handle the "load". Most pacemakers today only attempt to mimic this via an accelerometer inside the PM. That's only 1 data point compared to a couple of dozen your body uses. The PM only knows you are exercising because the accelerometer senses your upper body motion. Cyclists in particular are not well served since you can exert a lot on a bike without a lot of upper body motion. I understand there are some PMs that that can evaluate other physiological factors; in addition, there are some PMs that work best for cyclists.

P.S. Many home devices (e.g., Kardia) can't "see" PM pulses, so after a PM install, many of these devices become less useful. 

Pacemaker adjustments

by runpacer - 2024-07-30 18:23:58

Hi Phil. I ran long distance for 50 years. Although, as expected, I cut down on speed and distance. However, with a pacemaker and  a couple of cancers, I run everyday. The biggest problem is the frequent need to have the pacemaker adjusted specifically for running. It is not an easy task. There is a go-to setting that the tech and I fall back on. However, right now I've been running with the pacemaker setting is a bit off and I can feel that tightness in my chest and sometimes difficult breathing mostly during the first quarter to half mile of a run. Sometimes it was corrected so that I would not have to experience those sensations but then the pacemaker might speed up at night when I just move around in bed, waking me up or feeling as if my heart is racing like I'm in the middle of a run. I think you will learn over time the correct formula for your pacemaker adjustment so you can workout will come. However, it is a bit of a moving target. Sometimes, like now, I am on my longest break from seeing the tech even though that setting is incorrect. I get burned out from visiting docs and techs with all of the diseases I have. I wish you the best. 

Phillip

Thank you for all your replies

by Philmtb - 2024-08-06 11:24:47

I would just like to thank everyone, albeit a little belatedly, for their varied responses and it's always interesting and informative to hear your thoughts. Since I last wrote, I have now come off the blood thinners (eliquis / apixaban) I had been using since my DVT in the subclavicle vein at lead entry. I also had a balloon put in to push the leads back against the vein walls. This has certainly helped reduce swelling in my left arm. I have been told to take Adiro (aspirin) once a day for the next year. 

I still get sudden HR increases for no clear physiological reason, but I am training hard again and my fitness (FTP) is increasing. My next appointment with a Cardiologist is September 3rd before my cycle guiding begins in earnest. I will hopefully get some answers then and I will keep in mind some the points you guys raised such as response rate and pacing of the atrium and ventricles. 

Progress is progress no matter how small. 

Biking

by Tex61 - 2024-08-11 13:41:41

New to the pacer.   Use a garmin chest strap.  First device implanted 5 mo ago.   ER thing.  Third degree block while driving.  Lucky to have not wrecked.  God is good. 
 

I echo the riding concerns with both pacer response and idiots texting.  
 

I pretty much now only ride a fat bike on the beach.  Only hazard there are the holes the kids dig.   
 

Felt like the two lead pacer heart wasn't keeping up.    Found one of the top EP in Houston.  Took it all out and went back with three wire.  Ejection fraction was a bit low.  
 

Only three weeks in on the new one.  Had a few easy rides this week.   HR averaged 100 for the hour.   Didn't see the weird HR readings like I did with the first pacer. 
 

still taking it easy.     Love to ride and I'm encouraged by how many of you still exercise.   I'm 63 and love to row, bike and lift heavy things.   

Exercise+pacemaker+ monitoring

by Cbriezz - 2024-08-13 16:33:11

76 years young, been riding since age 4 from galloping racehorses to foxhunting. It's a life sport. Until I decided to up my senior riding game with some lessons a couple of years ago after a lengthy time out of the saddle. Long story short, no amount of adjustment could keep me from being short of breath and feeling arrythmias when trotting. I am convinced that the gyroscope like mechanism is set off by the gentle upper body movement that accompanies a good rider posting to the trot on a thoroughbred. Same thing happened when I though I'd take up jogging to get me outdoors and more active. 5 paces and I was sitting on the curb gasping. Bend over to pick up laundry basket, climb stairs with it and I'm out of breath. If I do knee bend, pick up same basket and do stairs there's no issue. 

I too bought a Kardia on recomendation from another cardiac patient who's cardio recommended it. However, the ads and my cardio surgeon/electrophysiologist  of 20 years says its useless in conjunction with pacemaker. 

So, I gave up my lifetime passion of riding, bend at the knees when lifting and keep my Kardia only for emrgencies of others. I am trying to adjust but I am not a happy camper. However, since I have 100% heart block, I AM happy to be alive these past 20 years and look forward to 20 more!

You know you're wired when...

You have a $50,000 chest.

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