Systolic vs Diastolic Blood Pressure: Which One Is More Important?

I'm Dr. Frita. And today I'm going to answer the question, of systolic vs diastolic blood pressure. Which one is more important? We know that high blood pressure is a leading cause of heart disease, strokes, and kidney failure. And so it is imperative that this condition be controlled.

But when it comes to the blood pressure which one should you focus on? Which one is more important? Systolic, diastolic, or should you just flip a coin? No need to worry, because I'm going to help clear things up, and by the end of this article you will not only know the differences between the two but also which one is more important.

What Are The Blood Pressure Numbers?

Systolic Blood Pressure:

Now the systolic blood pressure is that top number. And it is a measure of the force exerted on your vessels while the heart is contracting or squeezing.

Diastolic Blood Pressure:

The diastolic blood pressure is the bottom number. And it is a measure of the force exerted on your blood vessels in between heartbeats while the heart is relaxing.

According to the CDC, nearly half of the adults in the United States have high blood pressure, yet only about one in four actually have it under control. And this is a big deal because high blood pressure is a leading cause of strokes, heart disease, and kidney disease.

In fact, high blood pressure is the number two cause of my patients ending up on dialysis. So it is a big deal. When trying to properly manage blood pressure, it is important that you understand how to interpret it, including the difference between systolic and diastolic blood pressure. So in today's discussion, I'm going to go over the definition of high blood pressure. The difference between systolic and diastolic blood pressures. I'll also talk about what normal blood pressure is and how to interpret your blood pressure readings. I will also touch on the proper way to take your blood pressure. And I'll briefly go over some ways to prevent and manage your high blood pressure.

What Is Blood Pressure?

Blood pressure is the force that your blood exerts on your vessels. It's the pressure that your blood puts on your vessels. Blood pressure. There are two numbers when you're dealing with your blood pressure reading, systolic blood pressure, and diastolic blood pressure.

As previously mentioned, systolic blood pressure is the top number. And it reflects the force that your blood exerts on the vessels while the heart is contracting while the heart is squeezing. So when that left ventricle pumps, when it squeezes, and it forces out the blood from the heart, then that pressure during the peak of that force is the systolic blood pressure. That's the top number. And it tends to be the higher number.

The diastolic blood pressure is the force that the blood exerts on your vessels in between heartbeats while the heart is relaxed. It's the bottom number and it tends to be lower than the top number.

What Is A Normal Blood Pressure Reading?

According to the American Heart Association, normal blood pressure is when that systolic blood pressure is less than 120 and diastolic blood pressure is less than 80.

Systolic vs Diastolic Blood Pressure

Now to answer the question of systolic vs diastolic blood pressure, which one is more important? Many studies have revealed that systolic blood pressure is the greater predictor of future heart events such as heart attacks, strokes, and heart failure. And it is irrespective of age and more predictive of future cardiac events.

However, diastolic blood pressure, especially in young people, has been shown to have a very important role as well. So let's start with the systolic blood pressure. Studies revealed that systolic blood pressure is a greater predictor of future cardiac events, such as heart attacks, heart failure, and strokes than diastolic blood pressure. And this is irrespective of age.

Diastolic blood pressure, however, does have an important role, especially in younger people because studies also reveal that elevated diastolic blood pressures, regardless of the systolic blood pressure are also predictive of future cardiac events.

With that systolic blood pressure, it is especially predictive of future cardiac events when dealing with older patients, patients greater than the age of 50, and certainly patients older than 65.

Systolic Blood Pressure: Indicator of Future Cardiac Events In Older Adults

One of the theories is that as patients get older, their vessels tend to stiffen, tend to be less elastic, and not stretch as much when blood is flowing through. That will cause increased blood pressure, especially during the systole or that systolic phase of the blood pressure when the heart is contracting and the blood is being forced through the vessels.

On top of that, this force going through the vessels can cause shearing of the interior lining of the vessels which can lead to some disruption or some damage to the interior lining of the vessels. When this happens, it can promote inflammation and it can promote the buildup of cholesterol laid in plaques, leading to atherosclerosis.

Now take those things and combine them. You already have stiffed blood vessels in older patients, and now you have atherosclerosis or plaques. All of this will lead to a narrowing of the blood vessels and so during systole when the heart is contracting and the blood is being forced through the blood vessels, that can increase the blood pressure. And again, this high systolic blood pressure is more predictive of future cardiac events, especially in patients over the age of 50.

Diastolic Blood Pressure: Indicator of Future Cardiac Events In Younger Adults

Now, even though studies have revealed that systolic blood pressure is more predictive of future cardiac events than diastolic blood pressure, diastolic blood pressure in and of itself, when it's elevated, regardless of that systolic blood pressure, has been found to also be predictive of cardiac events.

Again, when the diastolic blood pressure is elevated, even when the systolic blood pressure is not, it has been found that diastolic blood pressure can be predictive of cardiac events, especially in younger patients.

There was a 2019 study, an eight-year-long study that had about 1.3 million participants. And it found that, again, even though the systolic blood pressure was more predictive of cardiac outcomes, when there were elevated diastolic blood pressures, regardless of the systolic blood pressure, they also were predictive of cardiac outcomes.

There was also a study published by the American Heart Association Journal Circulation, looking at blood pressure specifically in younger adults. It used a Korean database of patients ages 20 to 39 years of age. And it followed the data for 13 years and looked at cardiac outcomes like heart disease, heart failure, and strokes.

And it was found that when the systolic blood pressure was elevated between 130 and 139, it increased the risk for a cardiac outcome in those patients by 36% compared to patients with normal blood pressure. The diastolic blood pressure was also found to be very significant in these young patients because patients who had elevated systolic and diastolic blood pressures, they had a 67% increased risk for cardiac outcomes when compared to patients with normal blood pressure. Diastolic blood pressure cannot be ignored.

Be sure to watch my video on the truth behind high blood pressure where I share the top most frequently asked questions that I get about blood pressure.

There was also another study published by the American Heart Association Journal Hypertension, in this study there were 26 years of data that were reviewed in patients ages 19 to 97. And it found that yes, systolic blood pressure was also very predictive of poor cardiac outcomes, but especially in patients who were less than 50, diastolic blood pressure also played an important role in predicting cardiac outcomes.

Which Blood Pressure Number Is More Important?

So which one is more important? The systolic or diastolic blood pressure? They're both important. Because yes, it is true, the systolic blood pressure is more predictive of cardiac outcomes, irrespective of age. But the fact that cannot be lost is that diastolic blood pressure that is elevated even when the systolic blood pressure is normal, can also be predictive of a poor cardiac outcome especially if you are under the age of 50.

So for all of my young adults who are listening and your systolic blood pressure is fine, you know, it's 116 or 117, yet you have a diastolic blood pressure that is 80 or greater for you, especially, those of you less than 50, that could be predictive of you having a stroke, a heart attack, or a heart failure. Both the systolic and the diastolic are important.

To learn more about managing high blood pressure, please be sure to read my book "Under Pressure: A Guide To Controlling High Blood Pressure."

Again, I am a board-certified kidney and high blood pressure specialist. And I wrote this book based on experience and years of research as well. Not only do I talk about managing blood pressure from a medical standpoint and with medicines, but I also talk about using food as medicine, lifestyle, and I talk about exercise.

I also discuss things like what to do if you don't have a budget that will allow you to go to the most expensive gym or to always buy the most expensive organic foods, I give a realistic, practical way to manage blood pressure in an integrative fashion.  Also, please make sure you watch my video on 15 foods to avoid if you have high blood pressure.

How To Manage Blood Pressure

An important part of managing blood pressure is to modify the risk factors that you are able to modify. Now, certain people with primary high blood pressure or essential hypertension will have risk factors that you can't really control. For example age. Over the age of 50, and certainly over the age of 65 can be a risk factor, you can't change that. Or if you have heart valve disease, that's a risk factor. You can't necessarily change that. But there are some things that you can modify.

If you have diabetes, yes, that puts you at higher risk, for high blood pressure, but you certainly want to do whatever lifestyle management to control diabetes that can help you control the high blood pressure. For example, if you are living with obesity, try to get to a healthy weight. You want to try to manage your blood sugar, which can help with high blood pressure.

If you are a smoker of cigarettes, that is a risk factor for high blood pressure. You certainly want to change that around and stop smoking cigarettes. Also, excessive alcohol use can be a risk factor for high blood pressure. You want to make sure that you're not drinking alcohol in excess.

In other words, don't just sit around and fall victim to high blood pressure and say, "oh, well it runs in my family. Oh, well, these are my deck of cards." You make sure you do everything you can to manage your lifestyle and consult with your physician to manage this high blood pressure.

It doesn't have to be the silent killer for you. If you found this article to be helpful and informative, be sure to share it with the people you care about. Also, please be sure to follow me on Instagram @dr.frita where I give you information on how I try to live my healthiest happiest life. I also let you know when I'm doing community service or when I'm having appearances on national news channels.  Also, please be sure to tune in to my podcast, Healthy Happy Life Podcast with Dr. Frita.