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British Heart Foundation
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How low should your Beta Blocker go?

Sorry if this sounds silly, but how low should a Beta blocker drop ur resting HR? I have been on bisoprolol 1.25 for two weeks (at night) and my Fitbit shows my heart rate is between 50 and 58 whilst I sleep. Resting HR during day is 62 but shoots up when exercising (140). Can BBs drop ur HR too low? Originally put on for tachycardia on exertion. Thank u.

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Hi Mollypet, do you check the fitbit reading against a manual reading. My fitbit often tells me my resting HR is in the 50's but when I take it manually it's in the 70's. Not all fitbits are accurate, mine certainly isn't but my husbands fitbit reading is fairly close to a manual reading. Worthwhile doing a comparison.

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Thanks

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Hi Mollypet,

My Fitbit HR was way out ( 10bpm) compared to the proper monitoring equipment at cardiac rehab.

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Thanks

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Yes, I agree - I wore Fitbit at rehab and it was far from accurate at times.

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Those numbers are a lot like mine although I don't hit 140 very often anymore (fitness regime helps to address that). Fit athletes will have pulse rates down in the low 40s (even high 30s). A resting heart rate of 62 is good (the average is over 80) and your pulse dropping into the 50s overnight should not present any issues. You are on the lowest dose of bisoprolol (max I think is 10mg)

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Thank u. I just feel lousy and sluggish on beta blockers and wondered if u could get bradycardia from beta blockers

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Miguel Indurain who won the Tour of France a number of times had a resting heart rate of 28bpm! I haven't got a fit-bit but my when measured by a nurse my lowest recently was 53 and corresponded exactly to my diastolic blood pressure reading. I was quite relaxed having waited for 10 minutes. I think you have nothing to worry about.

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Thank u Michael

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hi iv recently started 2.5mg bisoprolol. my resting heart rate dropped from 64 to 53 literally overnight. it goes to mid forties during night. i think that’s because i take it at night just now as i can be symptomatic to medication. but i feel fine. lower reading doesn’t bother me though❤️shion

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Thank u. It's probably not the cause of my symptoms then. Also congratulations for reversing type 2 diabetes. You must be delighted. I'm a type 1 for 25 years.

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oh thank you mollypet. never say never. everyone’s different and react different. if it’s worrying you get it checked out. stresss isn’t good for us and it’s better safe than sorry. have a great day❤️shiona

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I’m on 7.5mg, 5mg of it in the evening. My resting HR is low 50s, occasionally dropping to mid 40s overnight. I feel OK, particularly since my pace & ablate last month. I’m presently on ‘initial’ pacemaker settings and return for a ‘tune up’ at the end of the month. Then I’m hoping to be able to come off the meds.

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I understand Beta-blockers can reduce HR across the range by 10-20 bpm or more in some cases, so HR is affected at rest and also when exercising. It can be useful to track blood pressure alongside HR as Beta-blockers affect both. Use an accurate measurement method remembering you can take your own pulse at the wrist and use a watch to calculate (count pulse for 15 sec then times four). BBs can drop HR and BP too low so it's wise to track and speak to your Doctor if you are at all concerned.

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Hello Molly

On a recent Holter Monitor my overnight ( nocturnal ) resting pulse was recorded as

54 episodes of Bradycardia which I think I am correct in saying longest was 38 beats at 0127 in the morning, slowest was 22 beats at 0527 at 0528 I had a pause of 3 seconds !!!

7% of my heart beats were Etopic which throws your pulse a bit out of sync so it's a little difficult to get an accurate rate without a constant monitor. I am on 10mg Bisoprolol so in my case maximum HR I can achieve is 84 beats, walking quite quickly uphill !!!

I think it all depends on what is wrong with you as to why Bisoprolol is prescribed, but in my case it's to try to control ectopic beats and Heart Failure along with some other plumbing problems. After looking at Holter results Cardiologist has asked for another Stress MRI which is booked for next month.

I think but not 100% sure Bradycardia is regarded as a minimum of a sequence of 4 beats below 45 beats over a minute. ( difficult to do on a fit bit )

Sure someone will be along to either confirm or otherwise of definition of Bradycardia.

Regards

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My resting hr has always been low, 40-50, and when I was diagnosed with AF last year, I was immediately prescribed Apixaban and 2.5mg Bisoprolol. Didn't self-monitor my heartbeat much until after a cardioversion which corrected my AF, but then dropped my hr to 35-40. No problem except one brief spell of dizziness when out walking, but Cardiologist cut my Bisoprolol to minimum 1.25 mg and my resting heartbeat has now reverted to normal (for me) at 40-50. So yes, Bbs can drop your hr too low, but minimum dose shouldn't affect it too much. Ideal average hr is around 60-80, so 50-58 at night is lower than average but not worryingly slow imho.

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Beta blockers lower hr and bp. A rate in the 50s would not be of concern, particularly when sleeping, as long as you’re not getting symptoms associated with bradycardia such as feeling dizzy, faint, nauseous and/or breathless. I had to switch from bisoprolol to a calcium channel blocker as after losing a huge amount of weight the bisoprolol gave me symptomatic low hr - I was dropping into the 40s at rest and feeling awful with it.

As other people have said, as with most fitness trackers, fitbits are known to be inaccurate for HR and aren’t actually recommended for people with existing cardiac issues. That’s not to say they don’t have value, only not to get too hung up on what it says; best way to check your pulse is still manual.

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Thanks. Helpful advice.

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To be fair, I think Fitbit trackers are only inaccurate for people with cardiac issues. The technician at my recent pacemaker clinic told me that their own informal tests have shown them to be quite accurate compared to ECGs for normal healthy people.

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I’m currently on 1.25mg Bisoprolol and recording a resting heart rate of 43.

I found that as I increased the amount of running I did so my heart lowered, because of this my dose of Bisoprolol was reduced from 5.0mg to 1.25mg in stages but did little to my actual resting heart rate - see my previous post: healthunlocked.com/bhf/post...

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Thanks that was very helpful.

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Taken off same dose as you when my RHR dropped to 40 & my postural BP dropped low too. Couldn’t function & felt like I was wading through treacle.

Pat

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Did they wean u off the dose? I also take Perindopril 4mg for bp. That's about 120/80 so not too low?

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Speaking for myself, I believe I will be on Bisoprolol indefinitely. It might vary case to case.

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No need to wean off, I believe, because 1.25 is a low dose. The feeling of exhaustion improved after a couple of days, but I was still dizzy for a while, though I believe this was adjusting to Flecainide 50mg twice daily for my AF which I was prescribed about a week after stopping the Bisoprolol. They gave me a monitor for a week to check for any other Arrythmia that might be causing the dizziness but found nothing. I’m currently fine. Also take Apixaban 5mg twice daily.

Your BP sounds perfect.

Pat x

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Ah thank you for the advice.

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I was started on a dose of 5mgs per day. Giddiness and general slowness, so they cut to 2.5mgs per day, but problems persisted. I'm now on a dosage of 1.25mgs pd like you. I can function well but my resting heart rate is 49/50 bpm. It was as low as 45/46. My bivent pacemaker is set to kick in at 45, so I was extremely nervous.

My cardio was very reassuring though. His argument was that even a small dose was better than no dose, and providing I was unsymptomatic (no dizziness) and could function I shouldn't worry too much about the low resting heart rate.

As to the accuracy of the Fitbit I wear - I don't really mind, so long as it's consistent. It's accuracy might be questionable, although my GP remarked when officially checking my RHR after being sceptical "Oh yes, it is low!"

That was a year ago though and I'm still pumping.

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Thank u. Helpful advice.

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My HF nurse put me on 5mg Bisoprolol (2.5mg twice a day) to deliberately bring my resting HR down to 40-45. If it drops below 40 (which it regularly does at night), my ICD will pace it back up to 40. I was given the ICD because of Ventricular Tachycardia, but that hasn't recurred since I've been on my current cocktail of drugs (original heart attack was last June).

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Hi Mollypet.

I've been on 2.5mg bb's for just over four weeks and I'm finding my Hr sometimes dropping to the mid thirties.

What was your resting Hr before the bb's?

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Don't know but I'd guess mid 70s, and recently higher which was why I was originally put on BB

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To me that sounds about right. Before my ha I had excellent BP and an excellent resting Hr at around 65. Now, it's dropped to an average of 45. But, I think I'm going to go to my gp's to see if they will halve my bb, as I think I'm going too low.

I hope you get sorted out and I look forward to reading more of your posts. Take care.

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Thank you. I wish u well too. These BBs are tricky little things to get right I think.

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Hi Mollypet (lovely name!).

My husband is taking Bisoprolol 1.25 and has been since he was diagnosed with heart problems in June last year. He had a quad bypass in November. His blood pressure is quite low at 90/60 and resting (awake) heart rate is between 45-52.

Before he was diagnosed with heart problems his heart rate (pulse) was always 56 and his blood pressure was a text book 118/65. Not quite sure why he's still taking the blood pressure tablet! At a recent GP review, our doctor wasn't happy taking him off the water tablet and Bisoprolol. We hoped at least the 80mg Atorvastatin would be reduced - but no! Cholesterol level is 3.1!!!!

He has a Fitbit which reads nothing like the 24 hour BP monitor so be wary of results.

Good luck and look after yourself. xxx

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Thank u for the lovely message. Molly is my dog's name- hence Mollypet.

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That's nice. I'm an old cat woman. Our 18 year old cat is called Sprout (don't even ask!!). I couldn't make a nice name out of that!!

Hope you get on ok xxx

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I’ve been on 2.5mg for 5 months now and resting heart beat is between 48 and 50. Spoke to EP about these figures only yesterday and he said there was no problem at all, unless I feel dizzy (which I don’t). However he has agreed for me to drop to 1.25mg and see if I continue to not experience any AF symptoms. So don’t worry about the low heart rate unless you feel dizzy.

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