Bradycardia After Exercise

[mkoven]

So I don't know if there's a connection, but my hr was pretty slow yesterday evening--around 50. I have found I'm able to walk on a treadmill, esp if I increase incline, not speed, to really engage my muscles. I felt fine during and immediately after--even good. And during exercise, my hr was reasonable and ersponsive, getting up to the upper 140s, but i had worked up a good sweat. Felt like normal exertion. I did buy myself a hr monitor, and was shocked that my hr gets so low when awake. (I finally took it off, because I was getting worried about every dip). Any chance that exercise would later make me brady? I should say that it doesn't feel good-- I feel dizzy and chest pressure when it goes below 55. I am in that ten day window before my period, where things can get a little weird--so maybe hormonal???

My hr never used to be so low. Used to be low 70s upper 60s, before all my ans stuff kicked in.. And I feel best when it's in the upper 60s. some of it may be midodrine, but I dunno. It's not like I'm some well-conditioned athlete! I don't think it's low enough to talk about pacemakers, and I've been on monitors where docs have talked about my sporadic "mild" bradycardia, always sinus rhythm.

But it was odd-- even when I'd stand up, it was at 60! And I felt very lightheaded.

Any chance exercise could make me more brady in the hours following, triggering some sort of vagal response?

I'm wondering if some of my night-time chest pain could be from bradycardia??? I don't know how slow it gets during sleep--maybe mid-upper 40s??? though again, I've been on monitors at home and in the hospital and no one has ever been concerned.

[MomtoGiuliana]

I know I have experienced brady at times after exercise. I asked my POTS specialist about it. He said this is not an unusual development with POTS. Not very helpful, I know. He seemed unconcerned though. In my case, my hr will dip down shortly after exercise or even sometimes on standing (oddly)and then recover fairly quickly. I don't use a hr moniotr though so I don't know if it is occuring other times too and I just don't notice it.

[dsdmom]

I've had the same thing happen. It's always been a few hours afterwards.. my doc thought maybe I just pushed it too hard. Wasn't all that concerned - just told me to watch it.

[firewatcher]

Yup, exercise triggers the vagal response as well as acetylcholine. If you are hyper-responsive, you'll swing too far and get brady for a few hours.

Physiological background of HR recovery

CHRM2 plays a fundamental role in cardiac autonomic regulation (14). Activation of

cardiac vagal efferents leads to release of acetylcholine, which acts on cardiac CHRM2 to

decrease HR (6, 8). Several studies have shown that the main physiological mechanism

underlying post-exercise cardiodeceleration is vagal reactivation (4, 10, 24, 25, 35).

ajpheart.physiology.org/cgi/reprint/01193.2005v1.pdf

by AJ Hautala - 2006

[mkoven]

Maybe that's the reason exercise calms normal people down-- it does me too, but a bit too much, and not just mentally!