Systolic Vs. Diastolic Blood Pressure Reading: Which Value is More Important?

Systolic Vs. Diastolic Blood Pressure Reading: Which Value is More Important?

When a health care professional takes your blood pressure or you take your it yourself, the two readings are expressed as a ratio, for example, 120/80. The top number, which is the higher one, is your systolic blood pressure while the bottom number is your diastolic pressure. To give you a better idea of what each value is a measure of, let’s look at each value in more detail.

What Does Each Number Mean?

Systolic blood pressure is the force generated on the inside of blood vessels called arteries when your heart contracts. In contrast, diastolic pressure is the pressure placed on your arteries between beats, when your heart is relaxed. The force or pressure is measured in millimeters of mercury, or mmHg. For example, 120 mmHg/80 mmHg. Blood pressure at this level or lower is considered to be normal.

As you know, high blood pressure is one of the most common health problems men and women experience and the risk climbs with age. About 65% of people over the age of 60 have high blood pressure. Just as disturbingly, high blood pressure is on the rise in young adults and we’re even seeing it in a growing number of adolescents and teens, partially related to the rise in teen obesity.

You have two values – diastolic and systolic, and you now know how they differ. Is one more important than the other in terms of health? According to a recent study, having a diastolic or systolic pressure that’s too high is a health risk but for different reasons.

In a 2014 study, researchers followed almost 84,000 people for over 5 years. Not surprisingly, they found high pressure, in general, was linked with a greater risk for heart and blood vessel disease, but each was associated with a different type of health issue.

A high systolic reading increased the risk of heart attacks and heart disease more, whereas a high diastolic reading was linked with a higher risk for disease involving the large artery called the aorta that carries blood and oxygen from the heart to the abdomen and chest. In this study, people with an elevated diastolic reading were more prone towards developing an abdominal aortic aneurysm, an enlargement of the aorta. The problem with such an enlargement is that it can lead to rupture and a high risk of death. Fortunately, if you catch an abdominal aortic aneurysm early, before rupture, surgery can often correct it, and you can lower your chances of getting one by keeping high blood pressure under control.

Another study also showed systolic blood pressure is most strongly linked with heart disease and heart failure but also with kidney disease and overall mortality. People who have untreated high blood pressure are at greater risk for kidney disease because it damages the arteries that carry blood to the kidneys. In fact, hypertension is one of the most common causes of kidney failure. That’s why it’s so important to treat high blood pressure through diet and lifestyle or medications in some situations.

Systolic High Blood Pressure: How Does It Damage Your Heart?

When there’s high pressure in the walls of your arteries, it places greater force on the inner wall of arteries, enough to damage them. This damage speeds up the accumulation of plaque in the inner walls of the arteries that carry oxygen-rich blood. In turn, this reduces blood flow to critical organs, including your heart and brain and increases the risk that a plaque will rupture and form a deadly clot. That’s why high systolic blood pressure is so strongly linked with heart attack and stroke. As mentioned, the same can happen to arteries that carry blood to other organs, like your kidneys.

If hypertension goes untreated, it also forces your heart to work harder against the extra resistance created by arteries that are too tight. Over time, your heart enlarges in hopes of pumping with more force against the extra resistance. Along the way, the left ventricle, the chamber of your heart that pumps blood to your body become thick and stiff, and thereby less capable of generating force and pumping blood. One consequence of this is heart failure.

All in all, both systolic and diastolic pressure readings are important, although having high systolic blood pressure is most strongly linked with bad health outcomes. Another point to be aware of. Systolic pressure goes up with age, mostly because our arteries become stiffer as the years go by. That’s why you should monitor your blood pressure every few months after the age of 50.

Are You Destined to Get High Blood Pressure?

You might think high blood pressure is your destiny if you have a strong family history. Susceptibility to high blood pressure does tend to run in families, but lifestyle factors have a major impact on when and whether you develop hypertension. Research shows following a DASH (Dietary Approaches to Stop Hypertension) diet, an eating plan that emphasizes fruits, vegetables, whole grains, low-fat dairy and legumes and minimizes processed foods, sugar, and red meat lowers blood pressure and has other benefits like lowering LDL-cholesterol and improving insulin sensitivity.

Like the Mediterranean diet, another diet that lowers the risk for heart disease, the DASH diet is rich in plant-based foods. Foods from plant sources tend to be high in potassium, which is one reason why the DASH diet may be effective for lowering blood pressure.

If you could do one other thing to lower your risk for high blood pressure, buy a pair of exercise shoes and put them to use. Aerobic exercise relaxes blood vessels and improves the way they function. In fact, one study showed aerobic exercise lowers pressure even in people with resistant hypertension, a type not responsive to blood pressure medications.

The Bottom Line?

The systolic, or upper reading, is the one most strongly linked with heart disease, but both values are important with regards to your health. If your blood pressure is only mildly elevated, you may be able to lower it through diet and exercise. At the very least, healthy lifestyle habits will lower your risk for heart disease, the most common cause of death.



Circulation. 2000; 101: 446-453. doi: 10.1161/01.CIR.101.4.446

Centers for Disease Control and Prevention. “Measuring Blood Pressure”

National Heart, Lung, and Blood Institute. “Risk Factors for High Blood Pressure”

WebMD. “Genetics Affect Blood Pressure Risk”

Effects of the Dietary Approaches to Stop Hypertension (DASH) Eating Plan on Cardiovascular Risks among Type 2 Diabetic Patients: A Randomized Crossover Clinical Trial.

Medscape.com. “Hypertension in Women”

Hypertension.,2012; 60: 653-658 Published online before print July 16, 2012.


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