Which number is most important in blood pressure reading

Blood pressure is a key indicator of how well the cardiovascular system is functioning and can signal many diseases and conditions.

“It measures the pressure of blood flow to the vascular system. This is necessary for all the organs in the body to receive adequate nutrition and oxygen to function,” said Navid Kazemi, MD, cardiologist and chair of MountainView Hospital Cardiac Services Department.

There is a healthy blood pressure range, and having too high or too low blood pressure can cause serious, long-term health consequences. Unfortunately, the importance of healthy blood pressure often is overlooked, and many people with poor blood pressure may not realize they’re at risk.

Decoding your blood pressure reading

According to the American Heart Association, an optimal blood pressure range is at or less than 120/80 mmHg. This is what those numbers mean:

• The top number (120) is your “systolic blood pressure.” It indicates how much pressure the blood is exerting while the heart is actively pumping into the blood vessels.
• The bottom number (80) is your “diastolic blood pressure.” It indicates how much pressure the blood is exerting between pumps. “Diastolic blood pressure is the baseline pressure in the blood vessels when the heart is resting,” Kazemi said.
• “mmHg” is the abbreviation for “millimeters of mercury.” Mercury is used to gauge pressure in many medical measurements.

Which number is most important?

Both. Having a high number in either systolic or diastolic pressure can lead to a diagnosis of hypertension (high blood pressure). However, systolic pressure tends to get more attention because high systolic blood pressure is a risk factor for cardiovascular disease for people over 50, and it can indicate major cardiac events.

Also note: Heart rate and blood pressure are not the same, and they can indicate different issues. The American Heart Association reports that blood pressure measures the force that blood moves through blood vessels, and heart rate measures the amount of times your heart beats per minute. Having a healthy heart rate does not necessarily mean your blood pressure is in a healthy range. Both measurements are important, but one does not replace the other.

Hypertension (high blood pressure)

Hypertension, the clinical term for high blood pressure, is a common and dangerous condition. “It causes persistent strain on both the heart and the blood vessels, which can lead to serious dysfunction,” Kazemi said. “This can manifest as weakening of the heart, as well as damage to the blood vessels, causing various organ failure in the long-term.”

There may be some symptoms that accompany hypertension — such as fatigue, shortness of breath and headaches — but in general, the condition shows no typical symptoms.

Hypertension can cause stroke, acute kidney failure, heart attack and blindness, among other ailments.

Risk factors for hypertension include age, high body weight, low activity level, poor diet, smoking, excessive alcohol consumption, high stress levels, certain chronic diseases (including diabetes) and a family/personal history with the condition.

Blood pressure naturally gets higher with age. In people younger than 60, 140/90 mmHg is considered high, but in people older than 60, 150/90 mmHg is acceptable.

What about low blood pressure?

Hypotension, or low blood pressure, is less common than hypertension, but it can cause serious health consequences. Chronic low blood pressure is associated with organ failure because not enough oxygen can circulate throughout the body.

When to get blood pressure readings

“A normal person who has never has high blood pressure does not require regular readings beyond their yearly check-ups,” Kazemi said. “Patients with a history of hypertension should be checked more frequently.” Talk to your doctor about how often you should have your blood pressure checked, and follow that schedule closely.

Habits for promoting healthy blood pressure

Blood pressure is greatly influenced by lifestyle, so most healthy people can properly manage blood pressure without medical intervention.

“Keeping body weight within a normal range, eating a heart-healthy diet, decreasing mental stress and having a regular aerobic exercise routine can have a profound effect on blood pressure,” Kazemi said.

Purpose of review: Diastolic blood pressure has traditionally been considered the most important component of blood pressure and the primary target of antihypertensive therapy. However, over 30 years ago important epidemiological studies pointed out the importance of systolic blood pressure, and research during the 1990s has strengthened this view. Unlike diastolic blood pressure, systolic blood pressure increases progressively with age, and in the ageing societies elevated systolic pressure is the most common form of hypertension. The characteristic changes of systolic and diastolic blood pressure with age lead to increases in pulse pressure (systolic minus diastolic), which has emerged as a new, potentially independent risk factor. In this review we compare the relative importance of various blood pressure components.

Recent findings: Generally, in studies in which readings of systolic and diastolic blood pressure have been compared, systolic blood pressure has been a better predictor of risk. Moreover, isolated systolic hypertension predicts risk better than isolated diastolic hypertension, and the treatment of both isolated systolic hypertension and combined hypertension has reduced cardiovascular events. There are no treatment studies of isolated diastolic hypertension. Pulse pressure reflects stiffening of large arteries and is associated with several cardiovascular risk factors. Pulse pressure also predicts events in epidemiologic studies, but elucidation of an independent role is hampered by the close correlation between pulse pressure and systolic blood pressure.

Summary: Epidemiological and treatment studies suggest that systolic blood pressure should be the primary target of antihypertensive therapy, although consideration of systolic and diastolic pressure together improves risk prediction. The greatest practical concern at the moment is the undertreatment of hypertension, especially systolic, and total cardiovascular risk.