Question Title: Abnormally Low Heart Rate

I recently went to the doctor - and in the course of the exam learned that my pulse rate (confirmed by EKG) was stightly below 40 beatds per minute. I had come in with complaint of insomnia - i.e. - no problem falling asleep but awaken before 4:00 AM and unable to fall asleep for normal # hours. I am in early 50's, and over past two years have lost 65 lbs, on a very strict low fat (restricted calorie) diet, and
an exercise program - running five times per week, some weight training (after having been a lifelong couch potato!). Blood tests had not shown abnormal thyroid readings - and if anything I feel stronger, and more energetic then I did prior to starting this diet/exercise regimen - i.e. I do not feel weak - which I understand is a symptom of bradycardia. Question: does this need to be investigated further, or should I just forget it?

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Dear Joyce:

Many athletes (especially runners) have low resting heart rates. As long as the EKG shows a normal sinus bradycardia, and as long as the heart rate rises appropriately with exercise, there is usually no problem. A low heart rate can sometimes cause dizziness or lightheadedness, in addition to fatigue, but this does not appear to be the case with you. An underactive thyroid can cause a low heart rate. Sometimes electrolyte imbalances can cause a low heart rate and this is of particular concern if someone is on a very restrictive type of diet.

Information provided here is of a general nature. Specific diagnoses and treatments can only be made by your doctor. If you would like to be seen at the Cleveland Clinic, please call 1-800-CCF-CARE for an appointment with a cardiologist at Desk F15.

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