HR dropping while on climbs

Had a PM (Medtronic Azure) for about 18months, going back a few times for technicians to retune. Can run fine with hr in the 165/170 region and consistent.

Problem I am having though is that when cycling it is not picking up movement correctly, in that when I start climbing, half way up a hill it thinks I've stopped moving so starts reducing the HR. Wouldn't be so bad but leads to basically hitting 'the wall' , dizzy and wandering a bit on the road. Not good with traffic!

Anyone else had similar issues?



rate response

by Tracey_E - 2020-08-10 09:39:47

Rate response depends on movement to raise the heart rate. With cycling, the chest doesn't move much so it doesn't sense the movement. It's best to stop before you hit the wall, that's super hard on the body. You can talk to them about it but most rate responses are not good for cycling. There is one out there that use breathing (minute ventilation, Boston) and another that uses CLS (closed loop simulation, Soren) which I do not understand but I know it learns you and does not use solely motion. Unfortunately if you have one that only uses motion, cyclying is going to be a challenge. 

I'm afraid you don't have the right PM for your lifestyle

by crustyg - 2020-08-10 10:42:07

Look away now everyone if this is becoming boring for you.

As you say, there's not a lot of upper body movement in road cycling, so if you have Chronotropic Incompetence (CI == inability to raise HR appropriately, very common with SSS), then your PM has to provide the HR increase, but there's no sensor signal to feed into the rate response algorithm.

Arguably, BostonSci's Minute Ventilation (depth of each breath * number of breaths per second) is the best technology for this requirement, but it's not without its problems or challenges. But it does work when set up properly.  Without something like this the Surrey Hills are going to be a nightmare for you.

I don't think there's a practical answer to this for you.  Mountain Biking produces a *lot* more upper body movement, and if you have the accelerometer tuned for that you may well get all of the HR increase that you need when going uphill.

Paddling the PM is a sort of answer (some folk use it to assist climbing stairs) but I don't think it's practical on a road bike for any length of time.  Perhaps a personal massager taped across the PM might do it - I'm not being entirely facetious, it might work.

I'm not being smug about this - I'm very lucky that my EP doc listened carefully to my athletic aims and implanted Accolade for me, even though he's a Medtronic man.

I feel for you.  Sorry.


Adjusting Medtronic for cycling

by frankmcw2 - 2020-08-11 02:02:32

I've had a Medtronic Advisa for 5 years and experienced similar problems until I found a Medtronic technician who had been working with athletes such as yourself. The adjustments he made to my PM are fairly simple and have resulted in boosting my heart rate to a higher level for cycling, hiking up steep slopes and other activities that don't generate a lot of upper body movement. As simply as I can write it, these adjustments can be made by your technician: 1.Make sure Rate Response is ON  2.Turn OFF Rate Response Optimization  3.Increase Average Daily Living rate to about 115 bpm (this is typically set at 95 bpm)  4.Set the ADL setpoint to the number ten  5.Set the UR setpoint to at least 120.  These changes will make the PM more responsive to light amounts of upper body motion. The trade off is that you will notice higher heart rates during your average daily living activities, but for me that is a price worth paying. Some cardiologists and technicians will be leery of making all these settings changes at once, however just making some of the adjustments will not work at all. Once the settings are changed (as described above) move around the medical facility as an immediate test to feel the difference. I have a short .pdf file that describes this adjustment in greater detail, if you would like me to email it.

Thank you frankmcw2!

by ar_vin - 2020-08-11 18:01:44

For the excellent pdf notes summarizing the needed settings changes for Medtronic pacemakers!

It was truly life changing for me to get those tweaks done by my PM tech (after review by my EP). I can now do a lot that I couldn't do post PM and before the settings changes per the above pdf notes.

For example this past Sunday I did a 15.8 mile hike with a total elevation gain of 4200+ ft. One stretch was a hill that gained 1500+ ft in 1.3 miles. I had no trouble and my PM just kept pacing me all the way up the hill - but only at 115 bpm as my legs struggled to keep moving. If my feet moved faster, my PM would pace me at a higher rate......But it was plenty to keep me cruising up that and many more hills all day long.

Since the settings changes I've been up to 13000+ ft several times on backpacking trips and day hikes, again without any trouble.

Of course it took a good couple of months post PM setting changes to get myself back in aerobic shape to push myself. 

This is pretty much what I was able to do well before my bradycardia diagnosis and subsequent PM implant.

BTW my PM is a Medtronic Azure XT DR MRI W1DR01; the settings should work  for most recent Medtronic PMs.

Link to elevation profile of hike:


A note of caution

by crustyg - 2020-08-12 05:04:19

It makes perfect sense to increase the sensitivity of the accelerometer to drive the rate response algorithm as hard as possible so that you have a sensible HR and cardiac output for your preferred athletic activity.

The caution is to note that there are two possible problems with this:

1 It can increase your BP.  Control of HR is a major mechanism for short-term control of BP, and driving your heart hard will increase your BP.  In the athletic heart (often enlarged) this is particularly powerful as each heartbeat pushes a *lot* of blood out into the aorta, which isn't as elastic in our older years as when we were younger.  I suggest some checking with an automated BP monitor - every morning and night - for a week, and recording the results.

2 It *can* damage the heart muscle itself by overpacing the heart.  What you're trying to achieve is maxHR during activity and a relatively normal HR for the rest of the time.  A histogram of HR over time, where the height of each bar is proportional to the amount of time spent in that HR range is a good monitoring technique for this.  Over-pacing the heart leading to cardiomyopathy is a recognised complication of pacing (and I'm *not* talking about LV remodelling from prolonged RV-apical pacing): I've had two long periods of AFlut, and it's given me a mild cardiomyopathy (positive IVC sniff test on echo) and mild but persistent ankle swelling due to increased RA pressure.


I'll start a new thread

by ar_vin - 2020-08-12 12:30:27

Thanks much crustyg for your very thoughtful response!

I've been pondering this myself over the past year or more since I had these settings changed.

I'll start a new thread so we don't hijack this one; I'd appreciate your and others' comments there.

Link to new thread:


Follow up on Medtronic adjustments

by frankmcw2 - 2020-08-13 02:24:52

To ar_vin, I'm very glad the adjustments worked for you. I too experienced a dynamic difference in my ability to hike up steep mountains, cycle up steep hills, and even climbing a set of stairs. For those of us with rate response Medtronic Pace Makers, I believe these adjustments are the only way to overcome Chronotropic Incompetence. As a response to comments by crustyg, I would answer that 1.Neither I nor any of the patients of my cardiologist have experienced increased Blood Pressure from increased pacing by our PM's. My cardiologist in Arizona has applied this adjustment to many of his patients who were experiencing the same symptoms that I was. Also, I am posting my suggested adjustments only on the Exercise & Sports forum, where many posters are dedicated athletes trying to find a way to overcome Bradycardia and CI. 2.I have done a lot of research on PM adjustments and have found no evidence that too much pacing can lead to damage of the heart muscle. The adjustments I have suggested result in a slightly higher heart rate during average daily living activities but will not cause the pacing to exceed other parameters such as the Upper Rate setting. I believe that this adjustment is important to the pacemaker community and I would not like to see people scared away from it by undocumented claims of possible heart damage.

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So, my advice is to go about your daily routine and forget that you have a pacemaker implanted in your body.