Heart feels weird

  Hi I've been diagnosed with under activate thyroid and well, long story with the very careless doctors but ....

I finally got to see an Endocrinologist and I starter a treatment with 100mg of Levo, I've been doing this for a year and some of the symptoms have faded  however there is a very weird feeling in the heart and around my left arm ( almost like if the heart can't handle it anymore), I have several checks with the cardiologist and all came back fine, including the treading machine test, does anyone feels the same,

Does under active thyroids affects your heart ?, according to the doctor I should not worry but how can I not worry??

 Your thoughts will help thanks

29 Replies

Maybe magnesium

The heart and its function is very connected to the heart.  Maybe post some blood test results with ranges so people can see what is going on.  How are your levels of B12 - Ferritin - Folate - VitD ?  100 mcg is quite a big starter dose if you have heart issues.

Maybe complete your profile too so people know and understand more about your condition - otherwise it is difficult to comment.

You could be having problems converting the T4 into the active hormone T3 especially if you have low ferritin.

Yes it does affect your heart 

I get flutters and sometimes I feel my heart rate is fast and sometimes get that weird feeling too. I'm on erfa 90mg at the moment n it is well tolerated but I hv gained weight, I'm tired on and off joint pains , irritable and trouble sleeping. I'm on 5 mg of melatonin every night and an additional 3 mg of melatonin lozenge plus 5 htp and that sort of helps . My hoarse voice is getting worse after the biopsy n now I'm also struggling to talk as voice v hoarse n I'm tired

Do you know why you're gaining weight? it does sound very much like 120mg would be worth a shot.. tired, getting fatter, joint pains and hoarse voice... I would definitely try more meds..

You sound undermedicated but it may not be the only problem. Did the endocrinologist tell you how to take the dose properly? Did you get a retest and follow up appointment when you were given your high started dose, usually is 25 or 50 then retested and increased by 25 and again retested another 6 weeks until you are in the correct dose for you. You could be not converting properly because other things are low-that happens to us with thyroid problems. 

My apologies if you are taking it correctly but so many aren't so take first thing on an empty stomach with a full glass of water. Wait an hour before eating, two hours before any other meds and supplements and 4 hours away from iron and calcium. Otherwise you may well be not getting the dose you think you are as other things are stopping absorption. You can take it an night and some say they feel better that way but then has an extra point to get right, two hours after food as well. 

If that isn't what you have been doing then wait 6 weeks to get a truer reading then get tested. It you have been doing it right then get retested now and post your results and ranges-they differ from lab to lab and Keats see what is happening plus tests for other things as others have suggested. 

 do not take the morning dose before you have blood test done it can boost the results. Medication works on a long term basis so taking your them a bit late on blood test day won't make a difference

I also suffer with heart palpitations and fluttering and was told it was nothing to worry about.  This is the  first time in years (I have been on Levothyroxine for over 20 years), that someone has mentioned there is a correct way of taking it.  I just take it first thing in the morning on an empty stomach with multivitamins and glucosamine!!!!!!  

sorry edit still won't let me correct what my phone has got wrong Keats should be lets! 

This is education and not medical advice

Cayenne pepper is food for your heart take an eighth of a teaspoon (to start with unless you are used to it its got a kick)

 if you can handle it the recommended dose is 1 teaspoon 3x a day in some boiled water let it cool down to body temperature. build up to a whole teaspoon 3 x a day, In case you have a heart attack take a full teaspoon of cayenne pepper this will stop the heart attack.

your heart is being starved of food, if you have an abnormal heartbeat your doctor should review it, change your doctor even drugs.com states it is an issue.

 you need to listen to your body it is telling you something is wrong levo depletes calcium and iron out of the body you need to be taking something like the herb pigweed or purslane which is really high in calcium and iron also stinging nettles are great as these are all whole foods with heaps of nutrients in, iron is also excreted out of the body

If you are going to try any new food always rub it on your skin first to make sure you do not get a reaction wait 2 hours then dab a small piece on your tongue wait another 2 hours if no reaction then try a really small piece,

 or go online and look for poison testing for foods and follow there guidelines when your immune system is low always follow these rules especially for the drugs they give you Its amazing how many people I help who just ignore the side effects just because the doctor prescribed them the medication 

the body does not absorb calcium in water so milk is no good any oestrogen containing food/drink depletes testosterone out of the heart,

 co enzyme q10 combined with magnesium is also good for the heart and taurine is another essential

make sure you take any natural food like herbs 2 hours away from any medication you are on so as not to interfere with it.

Is your heart in rhythm I think the reason for my heart problem was caused by Levothyroxin ask your doctor to check your heart for afib ?

Ld31 try celery avocados, grapes,

you can get palpitations later on if your adrenal glands are affected or if youj are unable to utlilise your vitamins and minerals properly due to low stomach acid, which often goes together with underactive thyroid - I know I have it because I burp and all sorts when it is bad - and then you can have a problem absorbing your iron etc and this can lead to this and many other symptoms which people often confuse for thryoid or adrenal.

If you are not converting the levo you take into sufficient T3 then you can get heart problems from that. Have you ever had your Free T3 measured?


Another possibility : Hypothyroid people are often very deficient in minerals and vitamins. Low iron can cause heart problems, including chest pain and tachycardia. Have you got any information on your levels of ferritin? If it is low then working on increasing it might help your heart.


I had problems with irregular heart, beat dizziness when standing from sitting and out of breath when walking. All worse in the winter better in the summer. I went through a year of heart tests all negative! GP finally diagnosed Hyopthroid problem (discovered by me) took Levothyroxin for 5 months,,stopped as it was making me ill, toxic reaction. Heart problems continued, heart rate in the 40's.  GP still thinks it's my heart! Started on T3 and heart rate quickly modified and is now in the 80,s with no palpitations or problems. I have also taken supplements suggested by Paul Robinson (CT3M ) which I'm sure have helped.

Good luck

Who's  Paul Robinson and what's CT3M?

It all sounds similar to me I was worried that liothroyxine wa causing heart to thump but so stopp8but it's still intermittently doing it,I've got no energy  all over  again  and so down... I've  never heard of that stuff about  taking  levothroyine an hour before food ... I'm starving  hungry  all the time! 

Paul Robinson runs this website : recoveringwitht3.com/blog

and he has a facebook page too. He has also written several books which are listed on his website.

He is not a scientist or a doctor. He has hypothyroidism and has worked out a particular method of dosing T3 with lots of testing and trial and error (as far as I know).

CT3M is a method of dosing T3 which tries to mimic the way that T3 would be produced by the body. (CT3 M stands for Circadian T3 Method.) For people who need T3 but have problems tolerating it, their adrenal glands are often weak. The CT3M protocol tries to reduce the problem of low adrenals.

I too have experienced strange heart related issues.  Most of them have ceased since optimizing my various nutrient and thyroid levels.  However, I still experience, what feels like a "hard heart".  It feels like a rock is in my chest, pressing against my upper rib on the left side.  I still get this a lot.  My iron and ferritin are low, even though I take supplements.  Not sure why it is not rising.  Could this be the cause?  I also get this weird vibrating lightheadedness and waves of hot/cold sensations.

I am not taking meds, only supplements.

Any ideas?


This is the same feeling I have. It's a pain in my heart on the left side near my collar bone and sometimes a little lower. It's like a pressure. 

Mine is not near my collarbone, but more in the left chest, upper rib region.

Yes that's about where mine is. On another thyroid board someone mentioned that it could be too much estrogen converting to progesterone and that's strange because I had just started a very low dose of estrogen cream.  


Nutritional sufficiency and decent FT3 levels are what fixed my issues.  I was never able to reach a true euthyroid state on T4-only; my biggest problems with T4-only were high anxiety, shortness of breath while exercising, and fast heartbeat (normally my heartrate is pretty low).  If your doc hasn't checked FT3, do it and your heart will thank you, because the link between hypothyroidism and heart problems is clear.  Those 300+ symptoms of hypothyroidism include heart:


Hi snap!It seems to go with the territory! When will you see your  endo again? 

Don't worry...  and yes you can get odd feelings either from not enough or from too much medication..

When I was diagnosed with Hashimoto's I went to my GP with a string of symptoms that included Weird heart beats, palpitations, missed beats, all sorts of odd things. When I got properly medicate this all went away, but then I had a few wobbles (they call it a thyroid storm) and my thyroid goes into hyperdrive and I end up over medicated because I'm temporarily producing my own thyroxine, at these times I also get the weird heart feelings..

so.. you could be over or you could be under medicated, but you're not right.. If it just lasts for a couple of weeks then goes off for a few months then it's probably just a storm.

If it's all the time then your medication is not quite right.

A) too much - this would be shown by a high FT 4 and a very very low TSH

B) too little - this would be shown by a low FT4 and a TSH of over say... 2 (we're all different so this is subjective, personally I need a TSH of about 0.8 but some people feel fine at 2)

C) wrong meds - this would shown by a very high FT4 if you weren't converting properly and then you may be better off with T3 than Levo which is T4

One thing is sure.. it takes a bit of time to find your levels and what's right for you.. Is your vitamin D low? that too can muck about with your heart

None of it is seriously harmful over short periods, you have plenty of time to get yourself properly medicated before you need to worry... Give yourself another year to find your perfect med level and bear in mind that it may change..

Good Luck..

Take vitamin A with your medication and your heart problems should be sorted. It sometimes happens if there is too much iodine in the medication for your needs Vitamin A stops it affecting your heart. Hope this helps.

My heart sometimes feels weird, like it stops for a few seconds then pumps away again. I also notice my BPM is very low, sometimes only 42! 

Hello Oscarh, i often get a racie heart some time it feels like its coming out of my chest, only been having this since i have had an underactive thyroide so i would say don't worrie about it..If the Dr is saying its Ok then just enjoy life. Sometimes if i am on too much thyroxine my heart races but i don't worrie about it.

As I started to take Levo for under active thyroid, I thought I was having a heart attack, I had ecg, overnight monitors, walking tests and a chest X-ray. It dismays me that Doctors couldn't see that it was related to either the drug ( Levo) or the problem ( hypothyroidism)

I changed from Levo to a natural form and also was prescribed adrenal tablets, I take these at night time and magnesium +Vit C with breakfast.

Touch wood I'm fine virtually all my symptoms have gone, with the exception of breathlessness when walking and talking.

Hope you find what works for you xx

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