Exercise and resting heart rate

[Curious123]

Does anyone feel their resting heart rate is too low compared to what it usually is and their actual fitness level is not reflective of their lower resting HR? Based on max heart rate during a buggy run I think the RHR is being falsely lowered by hypothyroidism.

[Regenallotment]

yup, my resting heart rate before starting Levo was around 46, blood pressure was low indicating I was some sort of athlete too. Never picked up, not once. Now optimally dosed my resting heart rate is one of my best indicators of correct dose. Sits around 54-58. 🌱

[Curious123 in reply to Regenallotment]

Thanks. I do run but mainly just parkrun each week at the moment. Bloods seem to say all good but weight isn’t shifting either like it used to so might be time to consider adjusting dose.

[McPammy]

once I was taken to A&E as I was quite unwell at work. The nurse questioned how long I’d been training. I was overweight and had hypothyroidism. I looked at my body and looked at her. I said why are you saying that. She said well you have a heart rate of an athlete. I just laughed. She never put hypothyroidism alongside a low heart rate. My resting heart rate at that point was 37bpm. I felt awful. I was grossly under medicated. Now medicated correctly it’s roughly 57bpm according to my Nike Apple Watch. I was prescribed T3 which fixed everything immediately.

[hormonaljunkie in reply to McPammy]

People right… I had the same thing happen to me 2 weeks ago in A&E. It took me a sec to react… like are you actually really asking me if I’m an athlete after I’ve just given you my full medical background?!

Please show me which athlete has everything I have because that might actually give me some hope 🤣🙈

[ovended]

Mine is quite low. Around d 45ish now but when I’m a bit fitter can even be a bit lower. Overnight it does sometimes drop below 40 too.

[TopBiscuit]

Yes, I've been told numerous times that I must be an athlete based on my HR! I am reasonably fit but certainly no athlete. My resting HR is low 50s to high 40s and it will go down to below 45 at some point during the night. It does not go very high during exercise either.

[Hashihouseman]

yup me too. As others have commented. I am so fed up with doctors saying oh I must be very fit because my resting heart rate is low it's because being underdosed or even overdosed on T4 which lowers it catastrophically. I think it's one of the most profound aspects of hypothyroidism and it sucks the living daylights out of me. Very difficult to manage even with T3. There's a lot of evidence now that excessive T4 causes atrial fibrillation and my experience lead me to think that it is the heart trying to pump faster without enough tissue thyroid to facilitate it and when we are overdosed on T4 that reduces the rate of conversion to T3 so the heart muscle doesn't have enough. And starts to stutter.

[posthinking01 in reply to Hashihouseman]

Hi there - you are so right - I got told all my life that my blood pressure was perfect - later on I find out it was low (when having a major operation when I was 33 years of age) and I had an adrenal gland and thyroid issue down the line many years later - so low not necessarily good it could mean the heart/adrenals etc. are running low - most probably due to low thyroid issues - but your explanation as to why re AF was brilliant thanks. I once went to see 'my' consultant (not endo by the way) and he took my pulse and BP and said do you have any thyroid meds with you - your heart is running too slowly - I took some and he then did the tests again and he said 'that's much better' ! If you look at the chart for HR by age - here is the link -

forbes.com/health/wellness/...

you will see that 60 is the minimum - but can be lower for athletes - it would seem that the medical professional are looking at the lower numbers and believing what the chart says without thinking - could it be something else due to whatever ......? So an elderly lady coming to her appointment on a bus and her RHR is around 40 odd could be told she is an athlete ?

[Hay2016 in reply to Hashihouseman]

Yep, My RHR is also low 50-54 but on excercise on t4 only my max could be 210, add t3 a year later and suddenly max hr is normal. But t3 is gonna make my heart expire- I think not. No thyroid due to TT. It’s exhausting trying to explain.

[hormonaljunkie]

could have written this exactly!

I’ve always had a very low BP and heart rate. It’s actually gotten higher since starting hydrocortisone treatment for adrenal insufficiency, but I remember before that I would be walking at very fast pace and my heart rate would be 35. BP 90/54 maximum.

Nowadays pulse is a 45-50 at rest and 65 when power walking. Doctors always ask me if I’m an athlete, which is real funny given I’ve never been so unfit in my life. The last 15 years I’ve totally let myself go due to all the health conditions.

So to answer your question… I do think that in my case it’s partly genetic (that said most of my family have issues with high BP/ rate so maybe I’m imagining this!)

I always though that I must run low naturally. But I also think my conditions aren’t managed totally well and I could benefit from being higher. Also even if it were 100% genetic, doesn’t make it ok if it’s affecting you, creating symptoms that lower your quality of life.

I was in hospital for a week recently due to this. Pulse dropped to 33, low blood oxygen. They diagnosed me with Brady cardia but aren’t doing anything about it so that’s been helpful!

Good luck and keep us posted, it’s hard to meet people in the same boat

[posthinking01 in reply to hormonaljunkie]

Hi there - just a thought are you on enough thyroid hormone and enough steroid for your adrenal insufficiency -I also have AI and have to adjust steroid sometimes daily depending on what I am doing otherwise I will be in trouble - if it is hot that is a stressor for me and if it is cold it is a stressor on the body generally - if I am going on a journey and it is going to be stressful I adjust accordingly - one AI patient on a forum said she had to updose her steroid when her mother in law was coming to stay - which did make me laugh !

[hormonaljunkie in reply to posthinking01]

Thank you so much for sharing, I do usually do well on 20mg of hydrocortisone a day, but I forget that I'm meant to go up to 25mg a day if I feel anything is slightly off... be it whether I had insomnia the night before, woke up sniffly, or had work/ family related dramas to deal with...yet I fail to see how stressed I am in any given moment of stress, and then realise days later. So I hardly ever take the extra 5mg that I should be, trying to fix that!

I completely relate to you on the heat changes, or family dramas! With age my neurodivergence has become stronger, and that means I get overwhelmed even more easily than I used to....and my body just can't handle it anymore. I can feel the effects the entire next day!

[posthinking01 in reply to hormonaljunkie]

Hi another safety net is to take your blood pressure assuming you have one at home - get to know your levels and if it drops it is either low thyroid hormone or adrenals under pressure!

[hormonaljunkie in reply to posthinking01]

That’s a great way to keep track, thank you! I have a machine, after hospital thought best to start having a closer look at things… but I would never have thought to use it as an indicator.

[arTistapple]

Definitely. My story pretty much the same as other posters. I have had my current symptoms for decades. Distinctly Sluggish heart, slow to respond to anything necessary and then once it revs up it can go overboard. Tried exercise for many years just ‘fighting’ it. Now run out of steam altogether. Exercise definitely did not improve symptoms but may have ‘stayed’ them.