Pacer and VO2 max

I have been running (jogging) and am trying to increase my endurance and pace so that I can complete a 10k. I have found running late in life, after I got my CRT-P about 18 months ago due to a heart rate of 30. I was in atrial flutter, had an ablation which resulted in a Wenkebach. I have lost 40 pounds and run/jog 3-4 a week. My EP refuses to increase my maximum HR above 140, based solely on my age.I have had a stress test and show no signs of ischemia.  I use a Garmin watch to time my pace and heart rate. I cannot seem to increase my pace without becoming short of breath, and my VO2 max has topped out at 33. Any advice on how to advocate for an increased rate to hopefully allow me to run faster? 


Charm, And more charm.

by crustyg - 2020-12-21 17:23:32

I couldn't see your DOB in your profile, so I'll assume that you're older than me. My maxHR is quite a lot higher...

Keep emphasising that you want to exercise, you enjoy exercising and it's becoming an important part of your life, but you can't go as well as you would like because of your relatively low maxHR.

As a rule, Interval training (or fartlek if you prefer) is the best way to improve muscle stamina: you push the muscles into anaerobic activity (for a relatively short time - I used to find 30-45s of really strenuous running - 15-16kph at 4% or 5% was enough, followed by 4min of recovery, with 4 complete sets on the treadmill), which produces local hormones (paracrine factors) that promote local blood vessel growth, and then wash out all of the lactate, let the muscles recover (so at least 10% less work).  Over a relatively short time you increase the blood supply to the muscles => they can exercise at a higher level without becoming anaerobic =>more stamina.  Adjust the numbers to suit you - it took me years to get to my best treadmill interval sets...

Then go back to your EP doc with tales of achievement, remind him/her of that stress test with no ischaemia, ask nicely and gently remind the doc that it's *your* life, and your choice.  Be sensible about what you ask for - perhaps 150BPM.  Might be EP-doc's decision, but it should be your choice.  If your heart and exercising muscles are well matched, you should find that your muscles begin to feel like jelly as your sensation of breathlessness is starting to become unbearable. Not max speed from a standing start - that will make anyone's legs turn to jelly.  And interval training also improves the heart: the athletic heart increases blood supply as much by bigger (volume) and more powerful beats as it does by an increased *rate*.

In other words, you have to *prove* that you want/need and can cope with a higher maxHR.  Then, if maximum charm fails, change EP-doc.

Oh and well done about the weight loss: that's really impressive.


by AgentX86 - 2020-12-21 21:12:12

If charm doesn't work, ask exactly why he won't raise it.  There could be a very good reason.  The chance are that he's just conservtive (EPs tend to be that way) and charm may work, to get it raised slowly.

Thank you Crusty!

by Julros - 2020-12-21 21:25:47

I am 63, by the way, soon to be 64. I have been doing some interval training: after a 15 minute warm up jog, I run at a 178 step/minute cadence for 30 seconds, followed by a 30 second recovery, for 4 reps, and then follow with a 10 minute jog, and then a cool down. I had to cut back for a couple of weeks due to a tumble off my bike, so I am just now able to push myself again. Thank you for the tips. 

Not raising

by PacedNRunning - 2020-12-23 02:30:38


Since you have a CRT P I'm guessing you pace 100% in the ventricles. Doctors don't like to pace the ventricles at high rates for extended periods. This could be his reasoning. V pacing is hard on the heart.  I'm 49, and my max is 185bpm but I usually max at about 160's and 170's if I'm pushing it.  I try and keep my rate under 160bpm just because it feels better. I would ask your doctor if you can increase it to 150bppm or maybe try 140bpm first and then 150 etc and see how you do. Maybe you can explain to him how long you run etc. I would ask what his reasoning is. Unless you have other structural heart issues or arrhythmia' s, I don't see why they can't increase it.

Pacemaker adjustment

by seancrom - 2020-12-30 00:51:42

I am a very active person  about your same age and just got my CRT-P about 7 weeks ago .  My max HR is set at 140 BPM.  Are you able to get your heart rate up riding you bike because the pacemaker sensor is  motion or vibrtion based?  My pacemaker slows my heart rate down when I slow down hiking up steep mountains and does not keep up with my resperation rate

Pacing and cycling

by Julros - 2021-01-14 14:06:27

My heart rate will increase to about 110 when riding up inclines on my bicycle, because they adjusted the sensitivity, I think. This took 2 different adjustments to get this response, otherwise 80 was the max I could acheive. My sensor is motion based, so I understand that makes it difficult for it to respond to cycling. When I jog, it quickly accelerates to 140, which is the max that the cardiologist will allow. 

Pacing, cycling, running

by Shana - 2021-01-20 01:00:52


Caps are no fun - sorry Julros.

I'm nearly 100% ventricle paced and was having similar challenges with running. On each running attempt post implant, my heart rate jumped right to its wenckebach and cap. Painful. My cap is 170 (I used to race in the low 200's...probably why I have a pacemaker to begin with).

Two things that have helped, since my EP is uncomfortable increasing my cap based on occasional tachycardia runs:

1. Tracey's suggestion to align my beta blocker with my workout. Instead of taking it right before my morning workout, I take it at night - so it is 12 hours into the 24 hour dose and fully working.

2. I invested in a smart cycling trainer (wahoo kickr snap) and have been strategically building my cardiovascular strength thru Zwift (cycling workouts) and direction from a former triathlon coach. It's been a game changer.

Two months in, we slowly took the cardiovascular gains on the bike to running. We are making progress!  And even though I likely will never race/run at the levels I did pre-pacer, I can run slowly by making my heart more efficient on the bike. 

I hope you are able to convince your doc to increase the cap, but if not, just wanted to share feedback on how I chose to adapt. 

best wishes! 




You know you're wired when...

You have a maintenance schedule just like your car.

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.