The past few weeks I’ve noticed my heart rate dropping. I wear a fit bit and can see a daily chart on an app on my iPhone also. My daily heart rate has dropped from 60 at the beginning of January to now 53 daily. What concerns me is that there are many drops throughout the day to mid 40’s and as low as 38bpm.
I’m on T3 and T4 medication as I’m a poor converter and positive DIO2 gene test.
I’ve been going the gym 3/4 times a week since Oct last year and this January I decided to go on a 1000 calories per day, which I stuck to and managed to finally lose some weight, just 8lbs. I feel OK but the low bpm rate is concerning me.
I think maybe I need my bloods checking. Last time, only a few weeks ago, my results are as follows:
T3 5.0 (3.7-6.0)
TSH 0.69 (0.5-5.5) the range has changed from 0.35-5.50 this year!
T4 10.4 (7.86-14.4)
B12 867 (150-750) on injections
Vit D 90 (above 50) I do not supplement
Folate 11.6 (above 4)
Ferritin 39.9 (22-322) on ferris fum but not currently.
Cholesterol 4.9 down from 6.7
Anyone had low heart rate like this please. Mine has never gone this low before to 38bpm.
Am I exercising, dieting and it may be effecting my thyroid levels. I sometimes get dizzy
Thank you for any experiences or advice.
Pam
Written by
McPammy
To view profiles and participate in discussions please or .
Hi. I’ve just noticed that there was a typo with my T4 range yest I put in 24 instead of 14 for the top of my range. Sorry. No wonder you mentioned I need an increase. I’m bang in the middle.
When you edit the original post in a thread, you will also have the option to add (or remove) a single image. (To replace an image, remove the existing image, then add the new one.) This is the same process as writing a new post:
Oh ok I didn’t realise that. After resting all day yesterday and no gym again today, my heart rate hasn't dropped below 54 today so far. Every other day previously it has gone into 40’s and 30’s in the mornings and afternoon. So I’m going to rest for a few more days and see if things improve.
I got my blood results today taken on Friday afternoon 8 hrs after my last T3 5mcg. But I’d not taken my Levo before the blood draw. It looks like I definitely need an increase if I’m going to keep going the gym for my cardio exercise for T3 and T4.
T3 4.30 ( 3.7-6.0)
T4 9.50 ( 7.86-14.4)
TSH 0.54 (0.50-5.50)
I’m going to start with a third dose today. I’ve already tried this but I got pain in my adrenals, both sides, then after a week went all dizzy and weak my cortisol couldn’t keep up but I wasn’t exercising as much as I do these past few weeks back then in Oct when I had this increase.
Thanks for all your help. Just thought I’d let you know my recent results. Definitely T3 is being used up with exercising. My heart rate hasn’t been so low this weekend also as I’ve refrained from going the gym. I may go again a I couple of days.
If your heart rate is as low as 38 beats per minute I think you should call 999.
With a heart rate in the 50s I would call 111.
Edit : There is probably a difference between heart block and bradycardia but I don't know enough to know what that difference is. The heart block page is what came up when I googled "nhs bradycardia".
Thank you. In 2018 I was hospitalised as they thought I had bradycardia. I had loads of test during my 7 day stay. I didn’t have bradycardia thankfully. What I did have was very low T3 only 8% through my range. Since starting T3 everything improved. But since I’ve been dieting and exercising it’s gone low again.
If you haven't got bradycardia then the cause of your low heart rate is likely to be low thyroid hormones as your other replies have said.
I don't know if you treat yourself, but if you do I would suggest increasing what you take. Obviously getting a raise in dose from your doctor isn't that quick, but I would suggest asking your surgery for an appointment with the duty doctor and getting a raise in dose that way. I think a heart rate going down to 38 bpm classifies as an emergency!
Just come back from GP. He gave me a blood form to get my T3, T4 and TSH done today at my local hospital. So just done that too. He’s organised for an ECG on Monday. I think my levels me have dropped as I’m doing a lot more exercise.
Thanks Slowdragon. I too think I need a slight increase in meds. Not sure about T4 though as I can barely convert. Even when on Levothyroxine alone I could only convert 8%. I bet it’s because I’m exercising more and dieting. And as you say it lowers conversion which I have problems with anyway.
I going to see my GP this afternoon and get more bloods done before I increase anything. I think I’ll book an appointment with Prof W too. I don’t feel bad or anything I’m just concerned about this new low level heart rate to me.
I understand about DIO2 in that I’m a poor converter. I only convert 8% from a few blood tests. I tried to increase T3 a couple of months ago with a third dose. My lower back became painful, it was my adrenals trying to keep up then a week later I went very dizzy and struggling to walk. I had bloods done and was over medicated unfortunately.
Regarding and Levothyroxine increase. It was increased and then I went over medicated and only still converting 8% re my bloods in hospital. My GP thought I needed a T4 increase it didn’t work and Prof W quickly noticed about my low T3 and the conversion was very poor.
The trouble I find with T3 combo ...is it’s good when on typical, average energy output days ....but if you do 2, 3, 4 days on the trot of being too busy .....then can crash
On T3, as dose is inevitably suppressed....I still find I need to pace carefully. If do too much several days in a row .....suddenly can run out of energy ....thyroid won’t kick in to fill the gap. Recovery is pretty quick ....typically takes 3-4 days
Good advice. I generally go the gym every other day. I’ve tried 2 days together but I went all weak and thought I won’t be doing that again. I’ll leave it now until next Tuesday say. I’ve just had my bloods taken. It was 8 hrs since my last T3. So I should find out on Monday.
Yes I guess. But I was just hoping to get fit, lose weight and be that Phoenix rising from the ashes this year after the last two were terrible with my health. I’m going to take it slower.
Dizziness can also be a symptom of low Ferritin. Yours really is very low in range and definitely needs working on.
I am on combination Levo plus T3 and would not be able to function with your FT4 level. Maybe you need it higher. I'd increase Levo and see how things go.
Your ferritin is just 6% of the way through the reference range. In your shoes I would go back on the ferrous fumarate and once you've got it to optimal I would suggest trying to find a maintenance dose to keep it there. It can take a long time to find!
You can buy ferrous fumarate 210mg in boxes of 84 in pharmacies in the UK without prescription.
I’ve just completed a course of ferris fumerate 210mcg. I did feel better while on it and my heart rate was higher too. I just can’t seem to get it up. The highest I’ve managed was 50 still miles too low. It did get as low as 15 last year hence the GP giving me ferris fumerate. I don’t eat meat so this certainly doesn’t help me in this department.
I’ll speak to my GP today on any other ideas to get it up.
I had to take one tablet three times a day of the FF 210 to get my ferritin levels up, and it still took me 21 months to get it to optimal. I now take one tablet five times a week to keep it as optimal as I can. If I stop taking it altogether my ferritin drops like a stone. My serum iron is always poor, even with fairly good ferritin.
Do you take vitamin C to help your absorption of iron?
You might find this website of interest. Although with such low levels of ferritin you should be eating iron-rich food as well as supplementing iron - you can't just rely on food.
Hi. I was prescribed one ferris fumerate 210mcg daily. Maybe I need to take more each day. I’ve just spoken to my GP about it. He said it’s in range annoyingly. And won’t prescribe any more med just yet. Stupid letting me go under range before they’ll give me more. I want to avoid going out of range and get it up.
I remember when my ferritin was very low in range I got so weak I couldn't get upstairs by walking. I had to go up on my bum and rest after going up on each step. It took me about 20 minutes to get to the top. I restricted myself to going upstairs just twice a day, and one of those times was bedtime. My serum iron was below range too and had been for several years.
I remember once going upstairs during this time, getting to the top, and forgetting what I'd gone upstairs for. It wasn't the first time it had happened by any means. But on this particular occasion I burst into tears.
I will never trust a doctor with my iron levels ever again.
Gosh that’s awful. You must have been very low. Stupid Drs!! I had similar situation with my T3 too low, I could barely walk, luckily I live in a bungalow. I’ve got some ferris fumerate 210mcg so I’m going to start them today. Thank you for sharing your story I totally understand why your don’t trust Drs with your iron.
There has been a couple of occasions over the last years when I fell off the wagon. I was craving beef and rare too. Now I’ve found out I’m B12 deficiency and ferritin too. No wonder I was craving rare beef I ate loads one week and my friends couldn’t believe it.
No I haven’t gone gluten free. I did have the coeliac test and it was negative. So I’m still eating bread, not much, but mainly I eat veg, fruit, salad and protein like fish or quorn.
The predominance of Hashimoto thyroiditis represents an interesting finding, since it has been indirectly confirmed by an Italian study, showing that autoimmune thyroid disease is a risk factor for the evolution towards NCGS in a group of patients with minimal duodenal inflammation. On these bases, an autoimmune stigma in NCGS is strongly supported
In summary, whereas it is not yet clear whether a gluten free diet can prevent autoimmune diseases, it is worth mentioning that HT patients with or without CD benefit from a diet low in gluten as far as the progression and the potential disease complications are concerned
Despite the fact that 5-10% of patients have Celiac disease, in my experience and in the experience of many other physicians, at least 80% + of patients with Hashimoto's who go gluten-free notice a reduction in their symptoms almost immediately.
Going gluten free is a strategy that everyone with Hashimoto’s should try. In some cases, we see a complete remission of the condition; in other cases (88% of the time), the person feels significantly better in terms of bloating, diarrhea, energy, weight, constipation, stomach pain, reflux, hair regrowth, and anxiety.
Many clinicians report that eating a gluten-free diet may help improve thyroid function in nonceliac gluten intolerance. “Getting gluten out is primary for patients with Hashimoto’s, even without celiac disease,”
I do know what you mean and understand why. Being veggie and gluten free may be a little hard for me. I’ll see how I go as normally I’ve been good until this week with heart rate falling.
I have suffered from a resting heart rate between 43-45 and had an ecg last year to be told it was normal, I always felt fine within reason except always feeling a bit tired however since starting Levothyroxine it has slowly started creeping up so I have put it down to my poor thyroid function, if it’s abnormal for you and you don’t feel well it’s best to get it checked for peace of mind if nothing else xx
I’ve had low heart rate also for some years but I’ve not seen it this low before. I’m going to get me bloods done to see if any of my levels are too low.
I'm not sure how much I trust Fitbit heart rate - mine was typically around the low 40s, and I don't think it should have been.
I would say, low calorie diets lower your T3 levels substantially. A trial conducted put a group of women on a 1200 calorie a day diet, and found it lowered their T3 levels by 30%. Lowering further to 900 calories a day resulted in T3 levels dropping 60%. You're not much above that level of calories, so you will be affecting your T3 results quite substantially.
I think this could well be right as it’s been declining since I started dieting. Also ferritin too low. I don’t feel hungry or anything. I have breakfast, lunch and dinner. I just want to lose some weight and without exercise and diet I just can’t seem to lose one pound. I’ve managed to lose 8lbs in January finally my jeans fit me.
It's a tough balancing act to keep T3 up and calories low enough, but managing to lose 8lbs is great.
Make sure what calories you are eating come from nutrient dense sources is all, I think that helps the body to realise food isn't scarce, and it doesn't have to drop T3. Lots of veg
I haven’t read all of the above replies but wanted to say when I was unwell my heart rate was 30bpm! Funny I felt bad when I stood up 😳 It was recorded as brachycardia and thankfully the mention of pacemakers never came to anything!
My heart rate has improved with the addition of T3 (I have no idea what the level was when I was unwell, it was nothing to do with my thyroid apparently 😡).
Recently however I have tried no Levothyroxine and recently reintroduced levo and I’ve noticed my heart rate is lower again. It has climbed from usually being low 50s, to mid to high 50s and low 60s. Now it’s dropped to low 50s again.
So I would conclude it’s more of a T4 thing than a T3 thing. For me at least 😉x
I feel mine is often to do with T4 too. I’m on T3 but when I take my T4 I’ve never felt normal or good. I often feel dizzy about an hour later. It’s like my body doesn’t want it.
Well having spent the last year increasing T3 and decreasing T4, to the point I stopped my levo, my findings at this point are:
Too much T3 made my symptoms come back, ie muscle weakness, dizziness, poor eyesight/focus without any of the typical ‘over’ symptoms,
Too much levo (and I unsure what this is yet, I just know the symptoms stopped when it stopped) causes me heavy limbs, frozen shoulder, other achey joints,
No levo causes my heart rate to drop, tiredness to increase and head pressure and tinnitus to return.
I’m currently taking a slightly increased dose of levo than I plan to stick with to ‘boost’ it up a bit. Seems to be helping the head pressure and tinnitus but I don’t know if I’ll need to re-increase my T3 again.
It’s so much trial and error but whilst the T3 did increase my heart rate a bit, it seems T4 is the important factor here.
I wish I could make it to the gym like you - I know my low hr isn’t because I’m fit!! I’m no couch potato, I register 14-16k steps every day on my Apple Watch but I can’t seem to do any cardio without the head pressure etc starting again. I’m hoping this current attempt to rebalance levo andT3 might improve it.
I’m so sorry you’re having to rebalance your thyroid meds. It’s such a difficult journey. I’ve been there too so you have my heart felt sympathy. I can’t believe that I’m actually going to the gym after the way I was last year. I am determined for sure. I need to listen to my body and today I have after all the sensible suggestions I’ve had today. I do hope you get there soon. Be brave you will. I too go very weak and can hardly walk if my levels go over or too low. It’s all trial and error isn’t it. Wish we could all be better looked after by the NHS.
Do you know if the times it drops to 38 is a resting heartbeat? Physically fit people can have resting heart rates of around 40bpm. You have been going to the gym quite a lot and the heart doesn't take long to respond to cardio and become more efficient. 3 to 4 times a week is quite a lot for intensive workouts, I would aim for twice a week and do some gentle exercise at home to compliment. It depends how long you stay for. If it's just an hour, it's not too bad but it also depends on the training you are doing.
You risk burnout if you push yourself too much, especially with the reduced calories. It sounds as if this started since you dropped the calories so I might consider introducing some more back in or choosing healthier more sustainable carbs. Are you exercising on an empty stomach? If you do, you need to be careful because your body is not a fan of being starved and although you may burn more calories in that moment, it might slow down your metabolism for the rest of the day because your body goes into a slower mode in order to store some reserves again the next time you eat.
You're kind of telling your body that you don't know when your next meal is coming, so if you don't eat often enough or exercise on empty, when you eat again, your body will want them stores back. It can lead to slower metabolism in order to conserve the food you do eventually eat which is why skipping meals is bad for you because it causes the body to lay down fat for 'emergencies'. The dizziness may well be due to low blood sugar or fluctuating levels but it may also be down to heart rate which I think you will benefit from further investigation.
If people don't eat enough calories and are exercising quite vigorously, then you might find that weight loss can slow down, instead of what you might expect and this is also because you are only giving your body enough calories to just tick over, not enough to burn off anything extra. It's important to get the balance right and also not just count calories, but give your body the right kind of food that can sustain you. It's also about where the calories come from not just how many you have.
I, personally think it is best to eat a small, healthy and light snack before working out. Something that your body can break down and use quickly. It can prevent hunger and dizziness afterwards and also might stop those dips in your heart rate.
Eat at least an hour beforehand. A slice of wholemeal toast with peanut butter is great. Or a banana if you like them. A bowl of wholegrain cereal, or yogurt and granola/muesli or a nice smoothie made with skimmed milk or almond milk.
Exercise is a great stress relief but can cause stress if you are pushing yourself too much and over exerting yourself.
You are also eating quite a lot less calories and sometimes, this in conjunction with a lot of exercise can make your body go into a sort of rest mode to conserve energy which includes slowing the heart rate. Make sure that you spread your calories out wisely and don't leave too much gap between meals because this is when you might notice the dizziness and fatigue and your heart rate might dip.
Don't be too aggressive with the dieting and exercise. Losing weight takes time if you want to keep it off. It is fine to lose about 1-2 pounds a week but don't aim for more than that because it will drain you and might make you want to eat more to boost the way you are feeling afterwards.
Concentrate on the health benefits of exercise rather than losing actual weight. Skinny people can be much more unhealthy than larger people and weight is not always an indicator of good health. It is only a guide.
Hi. Thank you for you detailed reply. I go the gym in the afternoons after my breakfast which is normally a banana and grapefruit and after my lunch with is normally a sandwich and one biscuit. I only stay 45 mins. 30 mins on treadmill with running 20/25. Then 10 mins on rowing mc. I don’t think I overdo it. When I’m there I feel as though I could do more but want to pace myself and not run out of steam. I eat a healthy dinner normally tuna steak, egg and salad followed by an orange. Or some other homemade veggie thing I’ll put together. I think it’s the upturn in exercise and keeping to 1000cals daily now in week 6 is probably having an effect and my make converting extra hard for my body. I’m now waiting on blood test results done this afternoon at my hospital to check if my T3 is low. It worked out ok as there was an 8hr gap since taking my morning T3.
hi pammy. i’m not an expert but i am hypo and a personal trainer. eating 1000 calories is way too low in my opinion, especially if exercising. how many calories on average are you burning per day. as i understand it from the research a maximum calorie deficit of500 per day/3500 per week is suggested so that one doesn’t drop too low which has been suggested to drop metabolic rate ( which is already lower for those with hypo). certainly nobody should eat 1000 calories a day in my opinion.
my usual calorie burn is around 2500 because i’m very active ( although i suspect i burn maybe 200 less than fitbit estimate because their algorithm produces an average based on heart rate, weight, height and activity, but i’m hypo so i’m probably burning lower than average) . so when i’m dieting i would eat 500 less than this to lose a pound a week. i know when i went too low on calories my heart rate went down, i lost some weight but then gained back more eventually ( which again is theorised as being caused by crash dieting)
heart rate can also lower when we get fitter so it could be this too?
Very interesting indeed. Maybe I’ve gone on too long with 1000 calories. It’s week 6 now. My calories burnt varies. I go the gym 3/4 times a week. Never 2 days together or I feel weak in day 3. I only do 45mins a day then maybe a 30 min fast walk around my village. Normally I’m feeling pretty good. But concerned about my heart rate dropping to as low as 38. When I’m running for a 20 min period on a treadmill it goes up to say 172. My max hr should be 158 for my age. I thought I was being sensible but maybe my calories are too low as you say. Yesterday my fit bit said I used 3,244 calories and I ate 1328 which is quite high for me daily. I normally eat 1050 cals. I thought my Fitbit May be over egging it as like you say with Hashimotos who knows what you really burn off. I’m going to rethink this now. I appreciate your input especially as you are a PT. you must know your stuff and with you having a similar situation to myself too. Maybe 2lb a week loss is too much for me. I do feel ok. It could be my cortisol too as I’ve had very low cortisol also. But that was caused by too low T3.
I’ve just had my bloods done so on Monday I should know and make a decision from there.
you can see your average weekly/monthly burn on the fitbit app by clicking on calories for the day then looking at the charts. even if you are burning 300 less than fitbit tells you, 1050 calories are way too low! i would say try to eat 500-800 less a day than burning, or if that’s too much food then reduce exercise to more gentle. i know it’s a great feeling to lose a lot of water/fat in a short tine, but your body seems to be showing metabolic adaptation and all that will probably happen is you burn less calories and weight gain will result. if you take it slower your body will appreciate it!
It’s a pleasure, you have helped me too in the past with great info!
i remember when i first lost weight i was in a facebook diet plan group, there was a female coach who i worked with to help them understand hypo and hashimotos/ they really took it on board and did loads of research to help their clients ( i ended up doing a bit of online coaching for them for a while, after i lost the weight). they advise slow and steady weight loss, and they give realistic advice about calories in and fitbit readings etc. the male coach is very straight to the point no bull type, some people don’t like it, but it helped me. they are called team RH fitness and they are on facebook or app i think.
One thing to say is- if you have been ob low calories you need to go up slowly- by say 200 per week, so that your body /metabolism adapts back up to normal. the scales might slow down or show a water gain, but it’s not fat. in order to lose 1 pound of fat the human body needs to be in a calorie deficit of around 3500 calories, and on the other end in order to gain we need 3500 over our normal weekly calorie output.
i find a weekly chart of calorie in vs out, with comments alongside- such as “ period”, emotional eating, low exercise week etc, helps me to assess when i’m gaining or losing and why. the fitbit is an excellent resource so long as we can remember it might be slightly off but that’s easy to work around based on overall progress.
also- take progress photos and measurements - i gained a stone and lost a dress size when i started doing weight training - my waist was very small and i had lower fat levels so the scales weren’t the best way to measure progress
and obviously follow the advice above about free t3, ferritin etc,
Brilliant. I’ll check this out. I think I’ve just gone too low on my calories against my output.
Luckily tomorrow we’ve been invited to a dinner party to I will be eating more anyway. Then Sunday I tend to eat slightly more too. I’ll keep on logging my food intake on Fitbit and go up some and maybe only go the gym 3 times rather than 4 until I level out and my heart rate returns. I’m going to start ferris fumerate 210mcg today also as I have some.
Thank you very much for your valuable help.
Hey McPammy, low calorie diets cause low ft3 from somewhere I've read, basically your body goes into starvation's mode, lowering metabolism to hang onto some energy from a little amount of food you have. It's a good idea to re-check your levels. But 1000 calories is way too low to function. Also, your ft4 is low. If you say t4 causes your symptoms, you could swap t4 for more t3, but with such a low t4 level I'd be very unwell, but everyone is different
I’ve been for bloods at 3pm today. So I hope to get some clues from the results. Thank you for taking time to respond. I think I’m gonna up my calories and also take more ferris fumerate 210mcg starting today.
Ideally blood test should be as early as possible in morning before eating or drinking anything other than water and last dose levothyroxine 24 hours before test. Last 5mcg dose of T3 8-12 hours before test
I know and this I always do. Today was a bit different as Dr told me to go today and with it being Friday and all the delay that can cause. At least my T3 has a gap of 8hrs.
Could it be the low calorie diet? If you’ve only lost 8lbs and dizziness I wonder if 1000 calories is just not healthy. I’d stop counting calories and go for something low carb instead. I like Zoe Harcombe as a trustworthy professional on diets. ‘Stop counting calories’ is a good start 🤗
Content on HealthUnlocked does not replace the relationship between you and doctors or other healthcare professionals nor the advice you receive from them.
Never delay seeking advice or dialling emergency services because of something that you have read on HealthUnlocked.
T3 increasing my heart rate? Help please feel awful! 
Sudden jumps in heart rate and wired anxiety - undermedication? 
Erratic heart rate
