low resting pulse rate

I am a 30 yr old female. 5 feet tall and weight 200 lb's. I noticed in the last 9 months that my resting pulse rate is 55. I never paid attention to my pulse rate before until one time when i was in a clinic and was feeling very tired so I checked my pulse rate with a pulse oximeter, and it was at 55. And this is while sitting down. I am not like this all the time, i just check it when I am feeling very tired and weal. Is a resting pulse rate of 55 normal? Please help me?

[Pum]

I think that is a bit low.  Are you really fit?  Has your thyroid level been checked recently?  No urgency but just mention it next time you're at the doctor.

[Mozartcowgirl]

I would definately have your doctor check for a thyroid condition... HYPOPOthyroid to be exact.. make sure he does a TSH uptake as well..  my resting HR was like that too... being tired is also a symptom of hypothyroid.. there are othersa as well.. are you experiencing any other symptoms?

[macfan6]

If you exercise a lot 55 is normal, lots of athletes have a  slow resting heart rate down to 45. From what I've read 60 to 100 is normal. But with people who exercise a lot it can be lower. Wikipedia says 50 to 100 for an adult.

I wouldn't worry about it. I don't think you need a doctor. If you had thyroid problems, you would have other big symptoms.

I think slow resting heart rate is good. Means that you are calm, and helps keep down your blood pressure.

[jdb7560]

I also think 55 may be normal and good IF there are no other symptoms. Mine is around 50 and I had every heart test imaginable and my cardiologist says it's fine. Had thyroid tests as well. Nothing. For some people a low resting heart rate is normal. I would get checked out though by your doctor. Especially since you are concerned about it. Chances are it is nothing, but it is prudent to make sure.