Female, 30 years old.
So I've been taking only 25mcg of Levothyroxine since August 2020 which was upped to taking 25mcg one day and 50mcg the next alternating like this, I started this at the end of December and I have been noticing a higher and faster beating heart.
I have always had a faster heart beat I believe for a good few years, such as when exercising / going for a walk my heart rate can get up to 140-160 but would always go back down to 80ish within a good amount of time, however im noticing that this time its not.
Just wondering if my Levo is affecting this? My last TSH was this: Serum TSH level 2.67 mu/L [0.35 - 3.5]
In my experience, being undermedicated can cause a faster heartbeat. And you’re on such a tiny dose of levothyroxine it might be what’s happening. When you aren’t on enough Levo your body has to work much harder to do even day to day things, so your heart may have to work harder when you’re active.
Your TSH, assuming that’s a recent result, is too high for someone on thyroid hormone replacement. Does your doctor only do TSH? You really need to know what your FT4 and FT3 are doing.
Oh really! I thought if you’re over medicated maybe i would be getting the palpitations and faster heart beat but i didn’t know if you’re not on enough Levothyroxene that it could do that!
My doctor does only do TSH, normally i request more tests privately and pay so might have to do that again!
Thanks for your reply!
If you were on a much higher dosage of levothyroxine that might be the case—over medication can cause hyperthyroid-type symptoms like a fast heartbeat. But essentially with those results you’re undermedicated—it won’t be the reason.
Don’t be surprised if your doctor doesn’t know that though. Sadly many many GPs don’t know how to treat thyroid problems very well.
Thankyou so much, i was on the 50 every other day like i said but they actually told me to stop it because they thought i might have reacted to it but i felt better for the time i was on it.
When i asked to trial levo at all they weren’t happy about it and that was when my TSH was at 9.1.
Wow. I’d have been bed bound with a TSH that high. Kind of proves my point though...
It was definitely the right thing to start Levo. But you need more now. You’re still on less than a starter dose.
Really, what’s the starter dose? I thought that was 25mcg.
I have recently had a heart monitor fitted to check everything else but over the past few weeks my heart rate has been higher by far also more when i stand up!
25mcg is a starter dose for the elderly and/or those who have heart conditions or have a history of reacting badly to new medication). 50mcg is the usual starter dose.
Most people need at least 75mcg within 6m of starting, with many ending up on 100mcg or more a day. Once you start thyroid hormone replacement your own thyroid tends to stops making hormone after a while, especially if it was “on the way out”, so to speak.
You’re not topping up your own thyroid’s thyroxine production—you’re replacing it.
Thankyou i really appreciate you taking the time to explain it to me as i am really clueless on thyroid issues after only having it ‘diagnosed’ in august but really having had it since probably 2014 subclinical.