I recently had a second episode of Afib (first was six months ago), and the doctor put me on a small dose of the beta blocker metoprolol (lopressor) for at least the next couple of weeks. Since starting to take the drug, my resting heartbeat went down 4 or 5 bpm, but my exercise heart rate is way down. A workout that would get my heart rate around 135 (I’m still in the prep phase) last week only gets the heart rate to about 105-110 bpm. Is this ultimately a problem? Do I adjust my training zones down? Is it likely to impact performance if I can’t get my heart rate up?
Unfortunately it probably will affect your performance. You can’t get the same sympathetic drive that you used to, so your HR will stay lower.
I was on beta blockers for a short time a number of years ago - The digoxin dosages I was on to control a-fib were getting dangerous, and the episodes were getting more frequent and longer in duration. I found I had extreme difficulty with any hard effort - like you said, you just can’t get your heart rate up. after several weeks of increasing intensity and effort in my workouts i was able to get my exercise heart rate back up to somewhat normal levels. unfortunately, the a-fib episodes also returned as well. I had an ablation procedure shortly after that - and 6 years later I am still (largely) cured.
so, with the beta blockers in my system i couldn’t exercise, and when i forced the training intensity the effect of the beta blockers seemed to wear off and my episodes returned with a vengence.
best of luck.
J
Not a comment on your athletic performance but from a medical standpoint it sounds like you are on an appropriate dose of your medication…
I know that wasn’t your question but thought I would but a ilver lining on your discussion
That sucks that you’re having problems getting it up…
If you don’t mind me asking, what is a small dose? I’ve been taking Atenolol (20mg) and while it has had positive effects on my high blood pressure, I feel like I haven’t had too much problem getting my HR up when exercising. I’m going to talk to my doc this week about this and see if there are better alternatives.
Thanks in advance. Flo
I was taking 25mg 2x/day. However in addition to the heart rate issue, I was tired all the time. I went to the doctor for a follow-up after 10 days, and he switched me to a calcium channel blocker (diltiazem 180mg 1x/day). Both issues are better so far.
No words of advice, only sympathy. My a-fib episodes started in 2001 a month after I finished Ironman USA. This topic comes up from time to time here and I am always surprised at the number of people who also suffer from a-fib. I’ve been recommended for the ablation but have turned it down up until now however I think it’s time to revisit the issue.
I’ve been on cardizem for a few years now, small dose, relatively benign, still have the oiccasional a-fib episode. I think my HR is lower than it was before taking the meds, but ran Naples 1/2 on Sunday and HR pretty close to normal, max 151, av. 131, felt good all the way. First time I’ve used the HRM for ages, and it was interesting to me that the numbers that came up were much better (higher) than I would have expected. Maybe I’m just used to the beta blockers after all this time, or maybe they’re having no effect
Cheers
Barry
I’m on a low dose of beta blockers (25mg of Atenolol/day), and I also got told to cut back on my exercise (ie. triathlons).
I believe the point of taking beta blockers is to help keep your heart rate/blood pressure low because you have some sort of heart problem? What’s the point of taking beta blockers than doing everything you can to get your heart rate up?? Seems like a bit of a contradiction to me.
I’m on 20mg/day of Atenolol. I haven’t noticed any difficulty in getting the HR up. I talked to my doc yesterday and he indicated that for me, there’s probably no reason to change anything at this point (except getting off it completely (smile)).
With your dosage amount, have you noticed any negative effect?
I’m hopeless at taking regular meds, and when my routine changes I often forget to take them, then get in the habit of not taking them.
Then when I do start taking them again I really notice it. For the first few days I’m incredibly tired and need afternoon naps, and towards the end of the day I feel as though I’m in a daze and have real problems concentrating, and don’t feel comfortable driving. After a few days though, everything settles down again.
I had a break, and just went back onto them recently, and at the moment I’m seriously lacking motivation, and always feel tired, but I’m not sure if that’s because of the beta blockers, or because I’m not training, and am just feeling like a blob
Generally my resting heart rate (while unfit) is 65 or so bpm, but with the beta blocker, my resting heart rate is 55 or so, and if I lie very still, I can get it down to about 48.
I’m curious as to why people are taking beta blockers? For me, it’s a preventative thing for a potential aortic aneurysm, which is why I’ve been ordered to lay off anything too strenuous. What about others? I’d love to get back into a reasonable level of training, but don’t want to risk my heart exploding.
Thanks for the quick reply. I was put on Atenolol due to “minor hypertension.” It was probably job related. 
No heart condition was noted, but the prescribing doc felt that Atenolol would help my high blood pressure. The meds have helped in that respect.
Thanks for the quick reply.
What can I say, I’m having a lazy day…