Big Drop in Resting Heart Rate

[SunsetRunner]

I recently started working out every weekday. Cardio three days and lifting weights two days. This is my 4th week in, and I've been consistent, missing only two workouts during this time. 

My resting heart rate was between 60 and 65 before I started. It is now down to 56 bpm. I'm not working out hard enough to be considered an athlete. 

Doing some research online I found this on heart.org "In general, for adults, a resting heart rate of fewer than 60 beats per minute (BPM) qualifies as bradycardia"

I would have contributed the drop in RHR to exercise until I saw the bit about bradycardia. I'm not sure what to think and was wondering if anyone else has experienced the same. 

[EdmundC]

I think it would only technically be bradycardia if your rate doesn't go any higher, my Fitbit resting rate is currently 55 bpm but that's only the resting rate, I can exercise and it will go up to 120 bpm, I remember many years ago in the early 1970's wearing a Holter EKG monitor and seeing that my heart rate had gone up to 145 bpm for a few hours.  That was just a result of watching Bob Marley and the Wailers performing live on stage, with my friend sitting on my shoulders for entire performance because she was short and could not see the band while we were all dancing.

Basically if your heart rate is going up and down then you're probably good and healthy, bradycardia is only an issue if the heart rate can't go up when you exercise, and tachycardia is only an issue if your heart rate will not drop when you rest ... so you sound healthy.

[LZeeW]

@SunsetRunner    My background is physiology.  I looked at a few major medical sites -- Mayo Clinic, Cleveland Clinic, Johns Hopkins Medicine -- and they all seem to focus on pathological reasons for a slow heart rate.  None mention the effect of physical training.  I, too, attribute your change to physical training.

I've been wearing a heart rate enabled Fitbit since the Charge HR.  Always active, hardly a current athlete, but I was a distance runner in my younger days.  I don't think I've ever had a resting heart rate over 56 bpm.

[SunsetRunner]

Good to know. Thank you for that. I'll look into that more. For some reason the website I mentioned didn't state that at all. Would have been nice if they did. My heart rate can get up to 156 bpm or even close to peak when I lift weights and stays between 119 to 145 during cardio depending on the intensity. It's kind of all over the place depending on what I'm doing, so what you've said is welcomed new. Thank you!

[SunsetRunner]

Yep, the site I visited did too. The funny thing is I've looked into this before (a long time ago) and never read anything that mentioned bradycardia. 

[EdmundC · Accepted solution]

I think that bradycardia is normally only seen as a problem when the heart rate drops lower and does not raise when you increase your activity.  Resting with a low heart rate and working out with a high heart rate is just normal - essentially the heart rate is variable, cardiac problems are normally only seen when you get rapidly changing rates and ectopic contractions.  Here's a link that explains this at the mayoclinic - another very educational source is Dale Dubin on Youtube 

[t.parker]

@SunsetRunner when I was oebse and unfit my resting HR was around 50. Now, I'm fit and it's 39bpm. I was checked whether I had bradycardia and as long as I can elevate my HR this isn't a problem. Some people has lower resting HR. It's not only fitness related but also individual genetics.