Very low resting heart rate - what could be wrong!

Posted by isadora2021 @isadora2021, Dec 1, 2025

I have at times in my life been an elite athlete. Even then my average resting heart rate was 45. I’m far from elite now after stage 4 abdominal cancer treatment now NED !

I do walk my dogs every day and spend a lot of time gardening. Nothing massive!

Yet suddenly my resting heart rate is averaging 40-42 and my smartwatch has sent me alerts while relaxed watching TV that my heart rate has dipped to 39. It also happens sometimes when I’m asleep too. So fat I haven’t gone below 39.

I have recently had an ECG and an Echocardiogram. I phoned my GP today to find out if the results have come in. The nurse told me there is nothing amiss and my GP has written on them “No further action”.

What could be going on?! I am not on any medication. My blood pressure is normal. My weight is fine. I have naturally lost some through walking.

Just that I feel tired a lot of the time, breathless at strange times (like not when I’m exercising just getting the dogs breakfasted), sometimes dizzy when I stand up from crouching in the garden.

I am still surveilled closely and no signs of cancer in my blood tests or PET-CT scans. I am not anaemic but I am short of Vit D and on supplement.

All in all I am in good nick for a cancer survivor going on 4 years NED other than this recent very low resting heart rate. Strange.

Do I push for answers or just learn to live with whatever is going on?

Interested in more discussions like this? Go to the Heart Rhythm Conditions Support Group.

Hi Isadora2021,

l read with interest your post and can identify with you.

I underwent several ECG'S and an Echo. Like you l was given a clean bill of health and advised 'no further action needed and discharged from Cardiology.

Two and a half years prior to this, l was fitted with a implanted loop monitor. The loop was inserted under the advice of the Stroke Team as three years ago, I had a mini-stroke. I had never had any heart issues.

A week after being discharged by two cardiologist consultants, I received a phone call from the arrhythmia clinic. l was advised l needed a pacemaker fitted. I advised them several days ago l was discharged from Cardiology.

It came to light that whilst the mechanics of my heart is working perfectly, the electric circuit wasn't.

The classic symptoms of an electric problem are bradycardia (slow heart rate), atrial fibulation dizziness, breathlessness, low heart rate and tiredness.

I would advise you to ask for a referral to an arrhythmia clinic.

As l have found out recently, your heart rhythm maybe out of sync whilst your heart working perfectly well. A bit like the engine of a car being okay but the electrics cutting out.

Thankfully, it was the loop recorded that picked up that my heart rate was dropping to 40bpm when a normal heart rate is between 60 - 100bpm.

As a result, skipped beats were picked up on 13 occasions over 30 months, lasting between 3 to 4 seconds.

I personally haven't experienced all of these symptoms and put my energy levels down to aging. I have since been advised it's not uncommon to be asymptomatic and it's not a matter of 'if' l will experience them but 'when'.

I hope my reply will encourage you to speak to your arrhythmia clinic.

The positive l take from this it's treatable and has a life enhancing result.

Wishing you all the best to finding a solution.

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Profile picture for sueiso @sueiso

Hi Isadora2021,

l read with interest your post and can identify with you.

I underwent several ECG'S and an Echo. Like you l was given a clean bill of health and advised 'no further action needed and discharged from Cardiology.

Two and a half years prior to this, l was fitted with a implanted loop monitor. The loop was inserted under the advice of the Stroke Team as three years ago, I had a mini-stroke. I had never had any heart issues.

A week after being discharged by two cardiologist consultants, I received a phone call from the arrhythmia clinic. l was advised l needed a pacemaker fitted. I advised them several days ago l was discharged from Cardiology.

It came to light that whilst the mechanics of my heart is working perfectly, the electric circuit wasn't.

The classic symptoms of an electric problem are bradycardia (slow heart rate), atrial fibulation dizziness, breathlessness, low heart rate and tiredness.

I would advise you to ask for a referral to an arrhythmia clinic.

As l have found out recently, your heart rhythm maybe out of sync whilst your heart working perfectly well. A bit like the engine of a car being okay but the electrics cutting out.

Thankfully, it was the loop recorded that picked up that my heart rate was dropping to 40bpm when a normal heart rate is between 60 - 100bpm.

As a result, skipped beats were picked up on 13 occasions over 30 months, lasting between 3 to 4 seconds.

I personally haven't experienced all of these symptoms and put my energy levels down to aging. I have since been advised it's not uncommon to be asymptomatic and it's not a matter of 'if' l will experience them but 'when'.

I hope my reply will encourage you to speak to your arrhythmia clinic.

The positive l take from this it's treatable and has a life enhancing result.

Wishing you all the best to finding a solution.

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@sueiso Wow! Thank you very much for sharing that. I’m so sorry to hear you’ve had a mini stroke. Those signs that something’s not right are exactly what I have while tests so far are showing everything is structurally ok (other than non urgent minor leaky heart valves).

I’ll add that to my list of things to discuss with my GP. Thank you ❤️‍🩹

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Profile picture for pintosh @pintosh

My resting heart rate in the 50 -55 range. I thought this is low too. I get dizzy sometimes too, Recently I visited Denver, Colorado and I had breathing difficulty and high heart rate and blood pressure too. Both went up to in the 145-149 range. I went to Emergency of the University of Colorado Hospital. They did not do any intervention. They said Denver is a high altitude place and this happens to some people. I returned back to Texas and heart rate went back to normal and blood pressure went down but it is now below 120. However, it used to be much lower. I saw a Cardiologist in Texas and they repeated the ECG test and did the Echo test and now they gave me a diagnosis of LeftBBB (left Bundle Branch Block). Now they want me to do Nuclear Echo test. I do not want to do this test because of risks involved. I read an article that there are two Ph.D doctors in Mayo Clinic in Minnesota who developed a noninvasive technique to deal with heart rhythm issues. If you are interested I can send you a copy of the article if you leave your email or phone.
I also made an appointment with a Holistic Cardiologist in January. I want to find out what her opinion is about this.
Just an idea, you may also try to talk to an Holistic Cardiologist as well. BTW I am 78 year old health concious woman, gardening and growing plants and outdoors are my hobbies too.

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@pintosh Thank you for sharing your experience. Something else I need to keep in mind - blockages.

(I understand your preference to avoid radioactive tracers. It doesn’t worry me too much as I already have a negligible amount during my periodic PET-CT scan as tracers for a recurrence of my stage 4 cancer).

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Profile picture for sandw40 @sandw40

@cannon360 I think for some the Smart watch has become I source of just another ailment, anxiety. With every passing moment of precieved strange heartbeat it becomes the " go to" source for a digital answer and we often find the answer to be just an opening of a door to another question without an answer.
Regarding the inconclusive reading look at it this way. With the watch you only have 2 physical contact points to take a reading. At a medical facility they stick you with multiple leads physically stuck to your skin to assure a valid reading. Which reading do you think is going to be a better reading?

The watch is a decent way to get some basic information but it provides more questions than answers and adds the little extra jolt of anxiety that I think most of us can have a much better life without.👍🏼

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@sandw40 My smartwatch marks me highly on low stress!

Personally I would prefer to use the smartwatch’s basic information coupled with feeling dizzy and breathless to take to my GP. I am not anxious about it but I know something is wrong. The GP and other professionals will do their jobs and hopefully help me manage it so I don’t have a stroke out of the blue! Wouldn’t be nice

As a stage 4 cancer survivor I know how lucky I am to have some more time. Maybe if I’d had a smartwatch while the cancer was growing I would have had data at a much earlier stage to check out 🤷‍♀️

Indeed, each to their own

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Profile picture for isadora2021 @isadora2021

@sandw40 My smartwatch marks me highly on low stress!

Personally I would prefer to use the smartwatch’s basic information coupled with feeling dizzy and breathless to take to my GP. I am not anxious about it but I know something is wrong. The GP and other professionals will do their jobs and hopefully help me manage it so I don’t have a stroke out of the blue! Wouldn’t be nice

As a stage 4 cancer survivor I know how lucky I am to have some more time. Maybe if I’d had a smartwatch while the cancer was growing I would have had data at a much earlier stage to check out 🤷‍♀️

Indeed, each to their own

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@isadora2021 Your reply is correct in as you stated you are not anxious about the readings delivered by the device but I notice that there are many who do develop the need to check their wrist often for reasons other than checking the time of day. Yes your also correct that some of us remain anxiety free their entire life and others develop it for various reasons and it never leaves their side.
👍🏼👍🏼

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Profile picture for sandw40 @sandw40

@isadora2021 Your reply is correct in as you stated you are not anxious about the readings delivered by the device but I notice that there are many who do develop the need to check their wrist often for reasons other than checking the time of day. Yes your also correct that some of us remain anxiety free their entire life and others develop it for various reasons and it never leaves their side.
👍🏼👍🏼

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@sandw40 Having a smartwatch can also be fun and healthy! You can set up your watch to see what you want to see easily and go delving if you want other stuff!

For example, I like checking my watch for how many steps and miles/kms I’ve done during the day and then putting in some more. Parking away from the front of the car park. Taking the stairs not the lift. Walking where I can instead of taking the car. I set realistic achievable goals. Fun for me and many others you see looking at their watch faces!

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Oh for sure. It's that carrot out at the end of the stick for myself to see if I can do a bit better day to day👍🏼

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Profile picture for gently @gently

Isadora, congratulation on beating cancer.
Push for answers; ask for a Holter Monitor.
Low resting heart rate is common for elite athletes. And with abdominal cancer treatment low heart rate increases survival rates. But abdominal cancer and treatments can cause damage to the heart's electrical system that might not be evidenced on the few seconds captured on an office ECG.
Rainyday's advice is well taken.
You shouldn't have any trouble getting the holter.

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@gently

Better than Holter: Zio patch (attached to your upper chest, monitored for 2 weeks not just 1-2 days as is typical with the old-fashioned Holter monitor.

And don't wait six months.

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Profile picture for earther @earther

@gently

Better than Holter: Zio patch (attached to your upper chest, monitored for 2 weeks not just 1-2 days as is typical with the old-fashioned Holter monitor.

And don't wait six months.

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@earther Good to know! Thanks

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