Your blood pressure reading contains a hidden number — and here’s why it matters

You’re likely familiar with getting your blood pressure taken, the cuff squeezing your arm before generating two numbers. Yet this vital sign contains a third, lesser-known number that matters for brain and heart health : pulse pressure.

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While blood pressure measures how much pressure the blood puts on the arteries while the heart is beating and at rest, pulse pressure provides a window into how flexible and elastic the arteries are, a sign of cardiovascular health.

Doctors typically watch for high pulse pressure, which signifies stiff blood vessels, although it’s not been widely used to diagnose health problems, said Dr. Charles Hong, the chair of medicine at Michigan State University’s College of Human Medicine.

Even so, elevated, or widened, pulse pressure is an established risk factor for heart disease and stroke . It may point to conditions such as atherosclerosis, which is when plaque builds up in the arteries.

“Pulse pressure is actually a good number to have, because it reflects something else that’s going on,” Hong said.

How pulse pressure is different from blood pressure

When measuring blood pressure, pulse pressure is the difference between the top (systolic) and bottom (diastolic) readings. Systolic is the pressure on a person’s arteries when the heart squeezes and sends blood throughout the body. Diastolic is the arterial pressure when the heart is between beats.

For example, an adult with a blood pressure of 120/80 mm Hg has a pulse pressure of 40 mm Hg, which is considered normal.

High pulse pressure is considered a risk factor for cognitive decline — independent of blood pressure, which is itself tied to cognitive decline. For example, according to a study published last year in the journal Hypertension , high pulse pressure may slow processing speed by disrupting white matter in the brain .

New research published June 3 in the journal Neurology found a link between high pulse pressure and increased risk of dementia-related death in some people.

Geneticist Laura Raffield, a co-author of the new study, was surprised that pulse pressure, a “less well-studied metric,” showed a prominent link to dementia-related death.

“Pulse pressure, that doesn’t always get as much attention,” said Raffield, an assistant professor of genetics at the University of North Carolina School of Medicine. “But potentially this adds to the literature that it may be an important risk factor.”

The heart is a dynamic muscle, and some pulse pressure fluctuation is expected, Hong said. It increases during exercise, for instance. Pulse pressure also typically widens with age, as the systolic pressure climbs and the diastolic pressure dips.

However, a sustained pulse pressure above 40 mm Hg may be dangerous.

Based on the highly regarded Framingham Heart Study , every 10 mm Hg increase in pulse pressure results in a 23% higher risk of coronary artery disease.

The Mayo Clinic considers a pulse pressure over 60 mm Hg to be a heart disease risk, especially in older adults. According to a 2023 National Library of Medicine text, a pulse pressure greater than 100 mm Hg is high.

Picture a healthy blood vessel as a deflated balloon, Hong said. It doesn’t take much effort to reinflate it. On the other hand, “if you’re blowing into, say, a brand-new balloon, or a balloon that’s very stiff, you have to generate a lot of pressure to force the air in,” he said.

A pulse pressure that’s too low, or narrow, means the heart is unable to generate enough pressure to pump the blood, Hong said. A pulse pressure less than 25% of the systolic blood pressure is considered low.

The link between pulse pressure and dementia

For the new research, Raffield and her colleagues analyzed data from the ongoing REGARDS (REasons for Geographic and Racial Differences in Stroke) Study at the University of Alabama at Birmingham. This dataset of more than 30,000 U.S. adults 45 and older contains an oversampling of Black people, who are more likely to die of a stroke than their white peers. Raffield’s team looked at a subset of nearly 9,000 people whose average age was 64.

Dementia risk is driven by a combination of genetic, environmental and lifestyle factors . To streamline their study, researchers calculated genetic risk scores for 11 cardiometabolic conditions and risk factors, including high pulse pressure, atrial fibrillation and cholesterol levels .

After 14 years, more than 450 study participants had died of a dementia-related cause. People who had a higher genetic risk score for elevated pulse pressure had a 16% increased risk of dementia-related death. None of the other diseases or risk factors, such as Type 2 diabetes or coronary artery disease, showed a statistically significant link.

Raffield noted there may still be a link between the other conditions and dementia-related death.

“This is just one piece of the puzzle,” Raffield said. “It doesn’t exclude many other very important both genetic and clinical risk factors.”

Pulse pressure goes beyond genetics

Dr. Steven Nissen, the chief academic officer at the Cleveland Clinic’s Sydell and Arnold Miller Family Heart, Vascular and Thoracic Institute and a former president of the American College of Cardiology, said pulse pressure is a classic indicator of brain health, though he cautioned further research is needed to confirm a genetic correlation.

“It’s not the slightest bit surprising that pulse pressure would be linked,” said Nissen, who was not involved in the research.

Anyone, regardless of genetic predisposition, may develop high pulse pressure, particularly people 60 and older.

Raffield said that while having high blood pressure doesn’t guarantee high pulse pressure, the two conditions are related.

She hopes the study encourages doctors and researchers alike to take a closer look at pulse pressure as a dementia risk factor.

“This may be giving us extra information, particularly in older adults, about things like arterial stiffness and how well the cardiovascular system is functioning, and that may also influence things like perfusion (blood flow) in the brain,” she said.

How to lower pulse pressure

Pulse pressure is modifiable, just as with high blood pressure.

“When you treat blood pressure, you reduce pulse pressure,” Nissen said.

Nissen also recommends following the DASH (dietary approaches to stop hypertension) diet , which includes eating foods that are low in sodium and saturated and trans fats, and high in fiber, protein, calcium, magnesium and potassium. Regular exercise has also been shown to lower blood pressure.

Hong, of Michigan State, said the new findings are an important reminder to keep pulse pressure in check as a means of protecting brain and heart health in the long term.

“Get it under control, and then you may actually lower the risk of dying from dementia,” Hong said.