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Thyroid UK
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Fit Bit - recording high heart beat

Today I have done the usual household chores. I've noticed that when I so much as walk up stairs or bend down or to be frank do anything other than lounge around my heart rate is Fat Burn Mode 100+

At bedtime it can be as low as 56.

At rest now - slightly on edge - it is 66.

Is this really bad?? I'm on Levo and have just been upped to 75 every other day (50 the remainder) but only been medicated 6 weeks or so.

Thank you

7 Replies

Just to add - I felt like this prior to being medicated.


I got a fitbit for this reason exactly. My heart rate has been a bit all over the place, I will say it seems only to settle, if I am on a strict no sugar diet. R x


Do you feel ill? I'd be quite ok with 66 but I'm not you. Your heart beat will go up and down depending on what you do etc.

Earlier on in the year my heart rate was up in the 80s to high 90s and I felt really dreadful. I saw the doctor, had ECG and blood tests done on the spot, chest X-rays the next day and nothing was found even though the doctor knew something was wrong. It stayed like that for a few days then went back to normal and has been fine ever since.

I've read that a normal heart rate is between 60 and 100 and also that the normal resting heart rate is between 60 and 100.

I didn't feel at all well when my heart rate went up to the 80s and 90s and stayed up, yet it can go up to over 100 during exercise then it goes down to the 60s afterwards and I feel fine.

I would speak to your doctor if you are worried.

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Unfortunately some of us do have these symptoms initially when first on levothyroxine or when it is increased. We have to allow a number of weeks for our system to settle down.

When next blood test is due it should be the very earliest possible and fasting. You also allow 24 hours between your last dose of levo and the test and take it afterwards.

Always get a print-out of your blood test with the ranges and if you get one from the surgery (some charge a nominal sum for paper/ink) of your latest blood test and post it will enable members to comment. It is a big learning curve if we've to get well.

My heart was playing up before I was diagnosed and afterwards but hopefully you will settle down. Before being diagnosed our heart struggles as we've insufficient hormones.

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Blood pressure and pulse can vary with thyroid meds. When my pulse is consistently high, varying with activity, it's time to cut back. If too low, I need more. You're wise to note patterns, keep doing it, and see if things settle down as your body gets used to the levo.

Could be other hormones as well. I recently upped my dose of pregnenolone, and my BP, which had been stubbornly high no matter what strategy my very good doctor and I used, dropped 25 points, both systolic and diastolic. Having a full hormone and adrenal panel, like a DUTCH test might be useful in that case.

Minerals, like potassium, calcium, magnesium, or iron may have an impact, too.

So track your pulse and BP along with any interventions you try, so you can piece together what's going on.

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66 resting is a very fit heart rate. When I was overactive my pulse was 160 sitting still. Your heart rate - pulse- will go up the more strenuous your activity is. Even laughing raises it.

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That's what I'm worried about - I'm not fit!!

I can't begin to imagine what it must have been like for you with a pulse of 160 sitting still. Poor you


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