When Your Heart Beats Fast and Your Blood Pressure Rises: What to Know

You might think that a fast heartbeat — also called a fast pulse or tachycardia — would go hand-in-hand with high blood pressure. But, as it turns out, that's not always the case.

As the American Heart Association (AHA) explains, high blood pressure and a rapid heart rate are not the same. Your heartbeat is the rate and rhythm of your beating heart.

Your blood pressure represents the force of blood against the walls of your arteries, the blood vessels that carry blood away from your heart. It's measured with two numbers, one representing the pressure inside arteries when your heart beats (the systolic pressure) and one representing the pressure between beats (the diastolic pressure).

Indeed, people with high blood pressure may also have a high pulse, but not always. According to a review published in December 2012 in the journal Current Hypertension Reports, research has shown that only about 15 percent of people with hypertension have a resting heartbeat above 85 beats a minute.

"Pulse and blood pressure are related, but not in a consistent way," says Michael Bungo, MD, a professor of cardiovascular medicine at McGovern Medical School and UTHealth in Houston.

A normal resting blood pressure is 120 systolic and 80 diastolic, says the Cleveland Clinic. The numbers represent millimeters of mercury. High blood pressure, called hypertension, occurs when those numbers start to go up. Hypertension is dangerous because, according to the Cleveland Clinic, for every 20 millimeters of mercury rise in systolic pressure over 115, your risk for heart disease and stroke doubles.

A normal resting pulse could range from 60 to 100 beats a minute. The danger of a rapid pulse is less clear than the danger from hypertension. Although studies show that people with rapid pulse rates are more likely to have heart problems, doctors are not sure which comes first.

A high pulse may be a sign of a heart problem, but not cause it. A high resting pulse might also just be a sign of being out of shape, called deconditioning. In, fact deconditioning is the most common cause of a high pulse rate, according to the Cleveland Clinic.

Read more: Relationship Between Heart Rate and Cardiovascular Fitness

Exercise is a common cause of an increase in blood pressure along with an increase in pulse, but according to the AHA, they do not go up at the same rate. When you exercise, your heart beats faster. A rise in blood pressure may follow, but how much depends on your conditioning. People who exercise regularly, for instance, can double their pulse rate without increasing blood pressure.

"Someone who is in good physical shape has supple blood vessels that will expand to handle the increased blood flow from exercise," says Dr. Bungo. "A person who is not in good shape will have a quick increase in both pulse and blood pressure."

For instance, he says, "an athlete may have a pulse rate of 140 after going up 10 flights of stairs, [but] a couch potato may have that pulse rate after one flight of stairs."

Besides possibly being too slow or too fast, your heartbeat also can be out of rhythm. If you use a device or an app on your phone that measures your blood pressure along with your pulse, this may result in a warning of an irregular heartbeat.

"A few irregular heartbeats are probably OK — it could even be a glitch in your device or caused by a sudden movement," Dr. Bungo says. "If you keep getting an irregular heartbeat, you should let your doctor know."

According to the AHA, an irregular heartbeat, called an arrhythmia, can occur during sleep or during exercise and not be a problem. The most likely link between high blood pressure and irregular heartbeats is atrial fibrillation, a condition caused by abnormal electrical signals inside your heart. High blood pressure is a known risk factor for atrial fibrillation, which tends to increase with age and can raise your risk for a stroke.

"Both your heart rate and your blood pressure are important," says Dr. Bungo. "If one or both is abnormal, it could be a warning of a condition that needs treatment. Let your doctor know."

Read more: How to Quickly Lower Your Blood Pressure