Does hypothyroidism cause a fluctuating heart rate?

Question

Hi doctor,

I am a moderately fit female (running 6.21 to 9.32 miles). My height is 5' 6", and my weight is 149 pounds. I have hypothyroidism, and I am on Levothyroxine. My TSH is around 1.5 mIU/L. My question is about a fluctuating resting heart rate. According to my sports watch, my RHR can be between 80 and 41 bpm. It is the lowest two or three days after a run where I have struggled to keep my heart rate below 150 bpm, even while running slower than a walking pace. Is this something to be concerned about, or is it just a weird glitch? Please help.

Thank you.

Answer 1

Hi,

Welcome to icliniq.com.

You have chronotropic incompetence (an inability to increase heart rate with exercise). This could be a consequence of hypothyroidism. However, I understand that it remains persistently high, possibly due to autonomic disturbances. My advice is to keep exercising at a low-intensity level so that your autonomic nervous system becomes accustomed to it and slowly increases the intensity later.

I hope this helps.

Please revert so I can assist you further.

Thank you.