Thank You for your time and consideration,
Donni McMasters
Posted by CCF CARDIO MD - CRC on July 12, 1999 at 14:22:53Dear Donni,
Thank you for your question. Heart rate control is due to two influences. One influences the heart to speed up and the other to slow down. The "natural" or intrinsic rate of the heart free of all influences (i.e if the heart were placed by itself in a test tube) it about 100 beats per minute (BPM). The vagus nerve is the "brakes" on the heart. This nerve is under control of the parasympathetic nervous system (part of the nervous system we don't think about). The vagus nerve will slow the heart down to a typical rate of 50 to 90 BPM. Rates slower than this can be seen in athletes and in certain heart conditions. The "gas pedal" of the heart is due to the sympathetic nervous system. Various conditions such as exercise, fear, anger, etc. will cause the heart to increase its rate. The maximum heart rate that can be achieved is determined by age. A simple formula that can be used to determine maximum heart rate is 220 - age.
The a slow heart rate is not really "good or bad" but is based more on the physiology of the particular state of the heart. Certainly a fast heart rate during a brisk jog is "good" where that same rate during a nap may be considered "bad". Likewise a slow heart rate leading to any symptoms (i.e lightheadedness or fainting) would be considered bad but otherwise is not in and of itself a problem.
Information provided here is for general educational purposes only. Only your doctor can provide specific diagnoses and treatments. If you would like to be seen at the Cleveland Clinic, please Call 1 - 800 - CCF - CARE for an appointment at Desk F15 with a cardiologist.
