Decreasing resting heart rate (post TT, combo T... - Thyroid UK

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Decreasing resting heart rate (post TT, combo T4/T3)


Hey there, from time to time it happens that, given all constant, my resting HR goes on an up or down trend, over longer period of times.

This one is coming back from a longer period of higher RHR.

What would you say this means in terms of the substitution treatment?

I feel a little blue but nothing to give a hypo flavour. Seems normal.

Last week bloods were:

FT4 15.3 [12-22]

FT3 5.22 [3.1-6.8]

TSH 0.007 [0.27 -4.2]

Only unusual event was 10 days ago had a megadose vit D3 single shot of 600k IU, accompanied by proper vit K2, Mg+K and Ca supplements.

But this type of variation of RHR happened before, so I wouldn't say it's necessary correlated with that single event.

10 Replies

Essential to have good levels of vitamin D, folate, B12 and ferritin for synthetic thyroid hormone to work well

For full Thyroid evaluation you need TSH, FT4 and FT3 plus both TPO and TG thyroid antibodies tested. Also extremely important to test vitamin D, folate, ferritin and B12

Low vitamin levels are extremely common.

Recommended on here that all thyroid blood tests should ideally be done as early as possible in morning and fasting. Do not take Levothyroxine dose in the 24 hours prior to test, delay and take immediately after blood draw. This gives highest TSH, lowest FT4 and most consistent results. (Patient to patient tip, best not mentioned to GP or phlebotomist)

When also on T3, make sure to take last dose 8-12 hours prior to test

Is this how you did the test?

Private tests are available. Thousands on here forced to do this as NHS often refuses to test FT3 or vitamins

Medichecks Thyroid plus ultra vitamin or Blue Horizon Thyroid plus eleven are the most popular choice. DIY finger prick test or option to pay extra for private blood draw. Both companies often have special offers, Medichecks usually have offers on Thursdays, Blue Horizon its more random

Caesard in reply to SlowDragon

Hello SlowDragon and thank you for your answer.

I'm old school here, I know the tips and tricks. Yes, I can confirm 24 hours window before test.

My thyroid is removed and used to test the Trab levels until it went to 0.

TPO was always normal and TG was 163 [=less 115] all tested 2 years ago

-just got a D3 megadose shot earlier this month

-I do supplement B12 every 2-3 months

-ferritin is a little bit over max level by itself 448 [40-400]

-folate was a bit low but within limits 6.8 [2.7-16] tested in late 2017

What also happened is that I've broken one knee some time ago and stopped exercising. Normally this should rise my resting heart rate

blood pressure was always normal and the same is the sugar level.

Still, it goes down. Today RHR is 61 bpm :)


Would be useful to know the range of your HRHs & the time gradients for rising & falling?

Caesard in reply to MikeM46

Hello, all time minimum was 60 and maximum 78. I am 39 yo male.

This going up going down happens once or twice per year, not really dependent on the season and quite consistent, with no wild variation usually. This one you have here is the steepest ever.

Interestingly I checked my RHR trend the other day, and had the same peak over Christmas/early Jan. I put it down to being off work, eating more, and not exercising as much. Could it be Christmas indulgence?

Caesard in reply to Cooper27

It could very well be! Bloody December! :)

Yes, it might add on it.

Cooper27 in reply to Caesard

I've double checked, and my RHR went 15bpm higher, and the peak was also the 1-3 of Jan. I finished work on the 20th of Dec, and it was a steady incline from there. It's dropped steeply since I went back to work on the 3rd.

Caesard in reply to Cooper27

Wow! 15 is even more than my variation! Told ya' December sucks! :)

Quite interested in this HRH stuff myself since having an ICD fitted due to a classic low T3 outcome of dilated cardiomyopathy & struggling to continue competitive league table tennis despite a rubbish ankle screwed together many years ago.

Think your range is within the range for your age.

I hadn’t realised how complex the factors are that affect HRH ... some idea here although encased in a website for serious exercisers!

Anything there of interest?

Caesard in reply to MikeM46

Yes, I have been watching it for some time now and can confirm that there are many factors of interest here. Stress, activity level, emotional state, resting windows from exercising, smoking, sleep, overall state of mind, hormone levels, all are factors of interest.

I am not concerned as of yet as this values are still well within my normal range for my age, sex and activity level.

But this adjustment is quite steep, I would really like to know why :)

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