Racing heart: Can someone explain what's going on... - Thyroid UK

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Racing heart


Can someone explain what's going on....because this is quite scary! I often wake up during the night with my heart pounding and last night i woke twice with rapid pulse. I'm not taking any thyroid meds (tsh 4+) as drs say i'm normal but i read somewhere that excess thyroxine can get dumped in the system and cause problems like this. I don't feel hypo, more hyper with widespread muscle pain . It may have nothing to do with thyroid but i thought i'de ask anyway........someone might have something which case i really sympathise!!!!!!!!

11 Replies

Does sound similar to hyper!! When did you have last tests?

Are you taking any other medication?

Dogtired, TSH 4 is probably why your heart is racing, and it's because you are hypothyroid, not hyperthyroid. Normal just means it is within range. If you can find out what the range is you'll probably find TSH 4 is close to the top. When you have your next thyroid blood test arrange the earliest blood draw you can and fast, water only, as TSH is highest early and drops post-prandially.

dogtired in reply to Clutter

Thankyou both....1month ago i found myself in A & E with atrial fib & have just finished a 6 day heart monitor check. I hope i get a follow up appointment soon but i may have to visit gp before then if symptoms continue.......i'm wondering if hashis is involved but will have to have private test . Last thyroid test was in june.

Clutter in reply to dogtired

Dogtired, thyroid antibody blood tests should determine whether Hashi's is involved. Unfortunately, Hashimoto's can't be treated and NHS won't usually diagnose hypothyroidism unless TSH is over range, or FT4 below range.

baba in reply to dogtired

It may be your atrial fibrillation.


Long time ago when my thyroid began to fail I would swing between Tachy and Bradycardia, so could be normal Hashimoto's but get it checked with your GP.


I developed tachycardia when my iron levels were really low. I was also untreated for hypothyroidism at the time (TSH was a smidgen under 6).

Spareribs in reply to humanbean

ooh - was just going to mention have you had irons tested too...

Hi Dogtired - I do tend to agree possibly Endocrine issue. Many years ago,

I too ended up in A & E with similar. Learnt since I was hypothyroid (TSH

only checked at time which was 1.0 - normal) so do get FT4 & FT3 checked.

Adrenal exhaustion - probably due Hypo State. Extremely low iron & Salt.

It's really unpleasant to have a reactive/sensitive heart rate. And feeling

concerned about what's going on just makes it worse. Everyone is

different, but I was prescribed Propranolol to take when needed (eases

a fast HR), until my system settled down. But your Cardio Consultant

will have no doubt have advised on that. But, yes, get Iron, Thyroid &

maybe adrenal tests done. And post results on here for comment.

You may need to pay for private FT3 & adrenal saliva test. My best

dogtired in reply to QUE6T-33

Thanks for all your very helpful replies.....havn't seen consultant yet but will ask them to do the tests.

Your welcome.

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