Blood Pressure vs. Heart Rate: Learn the Differences

Your blood pressure and your heart rate do not necessarily correlate, meaning your pulse is not usually a good indicator of either high or low blood pressure.

A rising heart rate does not necessarily cause your blood pressure (BP) to increase at the same rate.

There are many misconceptions regarding BP and heart rate readings, primarily because the two are usually taken simultaneously by most doctors and by self-monitoring devices that people use at home.

Any confusion between the two readings usually clears up among patients who need to measure their blood pressure regularly, says Curtis Hamburg, M.D., a cardiologist with Miami Cardiac & Vascular Institute and member of the Baptist Health Quality Network.  These patients are usually on medications to control BP or have other heart disease risk factors.

“Most people who start measuring their blood pressure get the idea that BP and heart rate don’t correlate,” Dr. Hamburg said. “Medications for hypertension (high blood pressure) can slow or raise heart rates. That’s why we ask some patients to keep track of both readings throughout the day.”

What Exactly Is Blood Pressure?
Blood pressure, usually two numbers, measures the force the heart exerts against the walls of arteries when pumping out blood through the body. Systolic pressure (the top number) records the pressure as the heart beats and forces blood into the arteries. Diastolic pressure (the bottom number) measures pressure as the heart relaxes between beats. The elasticity of the blood vessels helps determine this number.  A reading of 120/80 mm Hg (millimeters of mercury) is considered normal.

The heart rate, a single number, denotes the number of heart beats per minute. Adult heart rates at rest can vary from 60 to 100 beats per minute. Healthy individuals who exercise regularly usually have lower resting heart rates.

The Body Tends to Keep BP in Check
When you are nervous or overexerted — for example, after exercising or climbing flights of stairs—your heart rate likely increases sharply. But your body tends to compensate, keeping blood pressure from surging at the same rate — unless you need medication to lower blood pressure.

Healthy blood vessels will get larger (dilate) to keep blood pressure under control. This is the case for relatively healthy individuals, Dr. Hamburg said, who is Medical Director of Echocardiography Laboratory at MCVI at Baptist Hospital Miami.

But the body’s response to overexertion varies for everyone, depending on one’s age and heart health.

“It’s such an individualized response,” Dr. Hamburg said. “You just can’t look at heart rate and know what’s going on with blood pressure in most people.”

Stress Tests
Cardiologists will order “stress tests” to determine the amount of stress and oxygen demand that your heart can manage before developing either an abnormal rhythm or evidence of ischemia (not enough blood flow to the heart muscle). The most commonly performed stress test is on a treadmill.

The tests help determine the effectiveness of treatments to improve blood flow within the heart vessels in people with coronary heart disease. Both blood pressure and heart rate are closely monitored.

“We measure how much oxygen the body demands and that affects both heart rate and blood pressure, but not in the same way,” Dr. Hamburg said.

Vital Facts
Here are the important facts to know about blood pressure vs. heart rate, according to the American Heart Association:

• Measuring pulse rate does not indicate high or low blood pressure. For people with hypertension, there’s no substitute for measuring blood pressure.
• Even though your heart  beats more times a minute after exercising or overexertion, healthy blood vessels dilate (get larger) to allow more blood to flow through more easily.
• Taking your pulse can measure your cardiovascular activity and oxygen consumption, but it is not a substitute for measuring your blood pressure.