What Causes a Fast Heart Beat?

It’s normal for your heart to beat faster when you’re startled or excited, but what if it occurs for no apparent reason? The heart usually beats between fifty and one-hundred beats per minute at rest. When it rises above one hundred beats per minute it’s called tachycardia, which is just a fancy medical term for a fast heart rate.

Tachycardia can be a normal response in certain situations and doesn’t always indicate an abnormally functioning heart. One factor that affects heart rate is age. Resting heart rates are usually faster in young people and gradually slow down with age. Some teens have a baseline heart rate in the nineties, while this would probably be abnormal for an elderly individual.

One of the most common causes of a fast heart rate is exertion or exercise. This is a perfectly normal response to the body’s need for more oxygen which the heart has to work harder to supply. Another common cause of a rapidly beating heart is fear or stress. A person who’s suddenly frightened can sometimes feel their heart beating rapidly in their chest. This occurs because the body releases the hormone adrenaline when under stress which causes the heart to pump harder and faster. The heart rate usually returns to normal once the frightening or stressful experience has passed. Some people who are chronically anxious may have a sustained fast heart rate. Again, the cause is related to the body’s release of hormones involved in the “fight or flight” response.

A fast heart rate can also be caused by medications and even certain foods. Two of the most common instigators are caffeine and nicotine. Cutting back on coffee and cigarettes can sometimes significantly reduce a rapid pulse rate. Another common culprit that can cause the heart to beat faster is alcohol. If rapid heart beat is a problem, these three triggers should be eliminated first. Diet pills and stimulant medications can also contribute to the problem.

Another cause of a fast heart rate is an overactive thyroid or hyperthyroidism. An overactive thyroid may also be associated with sweating, nervousness, and weight loss. This condition can be ruled out with a simple blood test. Diabetics often experience a rapid pulse rate when their blood sugar levels drop too low. Infection, particularly when associated with a fever, is another frequent cause of an increased heart rate and the heart usually “calms down” once the infection and fever are treated.

A rapid heart rate can, in some cases, be a sign of underlying heart problems, particularly in an older person. A fast heart rate that’s associated with shortness of breath, chest discomfort, lightheadedness, weakness, or dizziness should always be evaluated by a doctor, particularly if there’s been a recent change in the resting heart rate. The bottom line? Any sustained changes in heart rate, particularly when associated with other symptoms, needs prompt evaluation.

References:

The Merck Manual of Patient Symptoms. 2008