Slow heart rate

Is it normal to have a resting heart rate in the upper 30s/low 40s? I know that very athletic people sometimes have low heart rates, but I don't consider myself to be "athletic". I started doing 45 minutes of cardiovascular exercise 6 days a week a year ago. When I started I was 100 pounds overweight and my resting heart rate was between 90-110. I had 2 ekgs a few weeks ago because my doctor was concerned about a long qt interval, but I was nervous so my heart rate was 55 in one and 81 in the other. I have no symptoms. Should I call my doctor?  I really appreciate your help.
Thanks,
Colleen

[DeltaDawn23]

I think that low of a heart rate definitely should be looked at by your physician.  I believe normal is 60-90.  Mine runs in the 50's most of the time, but that is due to the beta blocker I take.  I imagine a heart rate that low would make you feel very tired.  Good luck.  

[is_something_wrong]

Hello.

Yes, you should contact your doctor, and possibly get a 24 hour heart rate monitoring, to see how your heart rate changes during 24 hours. An extra reason for concern is the QT interval (did you have a prolonged QT?) in which setting it's not desireable with a too slow heart rate, because the QT interval further prolongs with slower heart rate.

That said, if you recently lost 100 pounds and is exercising almost every day, the results aren't necessarily abnormal. Carrying around 100 pounds too much is heavy exercise to the heart! And when your weight returns to normal, maybe your heart is strong enough to keep a heart rate that low? Do you have symptoms with your slow heart rate? Any medications?

The most concerning part is maybe the QT interval, which you should get evaluated by a cardiologist if there is reason to suspect something abnormal.

[colleenway82]

Thanks. My pcp said there was a long qt on the ekg he did, but when I went to the cardiologist i guess it didn't show up on the ekg he did. But I am honestly still a bit concerned about the qt on the original ekg. I just recently started going to this doctor and really don't want to seem like a pest or a hypochondriac.