Question: What causes the heart to occasionally beat faster? My wife has had a clean bill of health, but sometimes her heart beats faster, then goes back to normal.

Dr. Hibberd's Answer:

Rapid heartbeats can be a normal response to stressful stimuli when the body perceives a "fight or flight" situation. Rapid heart rates without stress or exercise usually deserve more evaluation if your wife is symptomatic. If she is not symptomatic, but you are detecting random changes in heart rate, often a simple EKG or even a Holter monitor will settle the issue of whether this is normal or not.

The heart normally increases its rate when a demand for increased blood pressure is present or anticipated. Of course, many medications, appetite suppressants, decongestants, and stimulants — which include "energy" drinks often rich in caffeine — will commonly exacerbate elevated heart rates.

Rapid, irregular, or unexpected extra beats are best evaluated by your physician just to be sure nothing serious is trying to present itself. Rapid heart rates may sometimes also be seen with some diseases, such as hyperthyroidism (overactive thyroid states) or tumors of the adrenal. A rapid heart rate is only a part of a constellation of other signs and symptoms that will be evident to a skilled medical professional.