When you visit a doctor, you’ve probably had your blood pressure checked. The results come as two numbers—one on top and one on the bottom. For years, doctors have focused mainly on the top number, known as systolic pressure, as the most important sign of heart health.
But a new, very large study shows that the bottom number, called diastolic pressure, also plays a big role in predicting serious health problems like heart attacks and strokes.
Let’s break it down. The top number, or systolic pressure, shows how hard your heart pushes blood through your arteries when it beats. The bottom number, diastolic pressure, shows the pressure in your arteries when the heart is resting between beats and filling up with blood.
While high systolic pressure has long been seen as a clear warning sign, the diastolic number has sometimes been overlooked.
That may now be changing, thanks to new research from Kaiser Permanente, a major healthcare provider in the U.S. Their team looked at more than 36 million blood pressure readings from 1.3 million adults living in Northern California.
These readings were collected over a nine-year period, from 2007 to 2016, making this one of the largest studies ever done on blood pressure and heart risk.
What the researchers found was clear: both systolic and diastolic pressures matter when it comes to your risk of heart disease and stroke. While the systolic number has a stronger effect, the diastolic number is also important and shouldn’t be ignored.
This was true even when using different definitions of high blood pressure, whether the older standard of 140/90 mm Hg or the newer, stricter guideline of 130/80 mm Hg.
These findings support recent changes in health guidelines, which encourage doctors and patients to aim for lower blood pressure targets to protect heart health. The message is simple but powerful—both numbers in your blood pressure reading give important clues about your health.
So, what does this mean for you? First, it’s a reminder that routine blood pressure checks are more than just a quick test—they offer valuable insight into your overall heart health. Second, it means that you and your doctor should pay attention to both numbers, not just the top one. If either number is too high, it could increase your risk for serious health problems down the road.
This research, led by Dr. Alexander C. Flint, was published in the New England Journal of Medicine, one of the most respected medical journals in the world. It reminds us that science is always learning and evolving, and as we learn more, we can take better steps to stay healthy.
If you’re not sure what your blood pressure numbers mean, it’s worth asking your doctor. Keeping both the top and bottom numbers in a healthy range—through diet, exercise, and possibly medication—is a smart way to protect your heart and your future.
If you care about high blood pressure, please read studies that early time-restricted eating could help improve blood pressure, and natural coconut sugar could help reduce blood pressure and artery stiffness.
For more information about blood pressure, please see recent studies about How to eat your way to healthy blood pressure and results showing that Modified traditional Chinese cuisine can lower blood pressure.
Copyright © 2025 Knowridge Science Report. All rights reserved.
