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New research indicates the length of time blood pressure stays within a healthy “target range” is important for brain health. mixetto/Getty Images
  • Almost half of Americans have high blood pressure, also known as hypertension.
  • Maintaining healthy blood pressure may help stave off conditions such as dementia.
  • A new study builds on existing evidence, indicating that the length of time blood pressure stays within a healthy “target range” is an important factor for brain health.
  • Regular exercise and eating a balanced diet may contribute to healthy blood pressure levels.

Maintaining a healthy blood pressure has been previously linked to a reduced risk of developing dementia, among other conditions.

Now, a new study recently published in the journal Circulation suggests the duration over which blood pressure is kept within a “target range” may also be a critical factor in staving off brain disease.

The findings will be presented at the American Heart Association’s Scientific Sessions conference in Chicago November 5–7 and are considered preliminary until published fully in a peer-reviewed journal.

The study is believed to be the first to explore the association between the length of time blood pressure levels stay within a healthy target range and dementia risk.

Scientists at Beijing Anzhen Hospital in China examined data pertaining to 8,415 individuals, which was collected as part of the Systolic Blood Pressure Intervention Trial (SPRINT) led by the National Institutes of Health (NIH).

Participants had an average age of 68, and all had been diagnosed with high blood pressure — but none showed signs of cognitive impairment or decline at the start of the trial.

Blood pressure readings were taken once a month during the first 3 months of the trial to help determine the target range — aka “ideal” blood pressure levels.

Participants’ cognitive statuses were measured 2 years after the trial began and again another 2 years later.

Participants whose systolic blood pressure levels stayed within the target range for more prolonged periods were less likely to receive a probable dementia diagnosis.

In fact, for every additional 31.5% of time spent within the target range, the risk for dementia lowered by 16%.

The researchers stated that consistency is more important than having fluctuating blood pressure with an average figure that falls within the target range.

“Fluctuations with high and low blood pressure can be an added stress on our bodies,” Dr. Rajesh Gupta, an interventional cardiologist and associate professor at The University of Toledo College of Medicine and Life Sciences, explained to Healthline.

“Each organ system, including our heart, brain, and kidneys, learns to live within a certain blood pressure range, and fluctuations can cause organ stress or damage.”

Despite the implications of the new research, the study was a retrospective that looked at previously collected data, which means there’s a notable gap in the findings.

“These kinds of trials [such as SPRINT] can’t tell you what ‘dose’ of time in target range would make the difference,” Dr. Stanley S. Liu, a cardiologist at the University of Maryland Medical Center and assistant professor of medicine at the University of Maryland School of Medicine, told Healthline.

As such, the new research wasn’t able to explicitly state how long blood pressure should stay in a particular range, just that a longer duration is better.

There are two blood pressure measurements: systolic and diastolic. For the study, the researchers focused on systolic blood pressure.

Systolic blood pressure is the pressure your blood puts on your artery walls during a heartbeat. Diastolic blood pressure shows the pressure on your artery walls between heartbeats.

In a blood pressure reading (i.e., 130/82 mmHg), the first number refers to systolic, and the second is diastolic. Healthy blood pressure is considered less than 120/80 mmHg.

High blood pressure — also known as hypertension — is experienced by almost half of adults in the United States.

“Hypertension can occur with elevation of either systolic pressure, diastolic pressure, or both,” said Dr. Patrick Azcarate, a cardiologist with the Miami Cardiac and Vascular Institute, told Healthline.

What’s more, there are very few noticeable signs of high blood pressure — meaning many people are unaware they even have it.

“Some people will notice that they have a headache or feel off when their blood pressure is high, but most people do not feel anything,” Dr. Jeffrey Tyler, a cardiologist at Providence St. Joseph Hospital in Orange County, CA, told Healthline.

Age is a key factor in developing high blood pressure levels.

As people get older, Liu explained that “blood vessels become more stiff [or] less flexible, and blood pressure is tougher to regulate.”

Other factors that may cause high blood pressure may include:

High blood pressure can affect both the heart and the brain.

“While they may seem unrelated, blood vessel health and blood pressure is very closely linked with brain health and prevention of dementia,” Liu said.

“Brain blood vessels are vulnerable to damage from high blood pressure. We often see dementia caused by cumulative damage to the blood vessels that eventually injure the brain through lack of oxygen to brain cells (something we call vascular dementia).”

Damage to blood vessels and arteries due to high blood pressure is a primary cause of stroke — with research from 2019 indicating that 1 in 5 people who experience a stroke will develop dementia.

“We know that kidneys develop structural damage after being exposed to years of high blood pressure. The same is true for the heart and brain,” Gupta added.

High blood pressure is a risk factor for dementia that some people may be able to control. Here are a few ways you can manage your blood pressure on a regular basis:

  • Exercise. “This is the best way to reduce your blood pressure,” said Azcarate. “Currently, we recommend at least 30 minutes of moderate-intensity exercise 4-5 times per week.”
  • Control sodium intake. Your diet should include less than 2,300 mg of sodium per day, which can be difficult to do with a typical Western diet.
  • Eat a healthy diet. The research-backed DASH diet (Dietary Approaches to Stop Hypertension), which emphasizes fruits, vegetables, and nuts, can help get high blood pressure levels under control.
  • Get sufficient sleep. Adults should try to aim for 7 hours of sleep per night. “Sleep quality and quantity is incredibly important to maintain healthy blood pressure,” Liu said.
  • Check in with your doctor. You can work with your doctor to accurately measure and control your blood pressure. When necessary, blood pressure medications may be an option.

Regulating blood pressure has been linked to staving off conditions such as heart attack, stroke, and dementia.

Now, research suggests the length of time blood pressure remains within a healthy target range is also critical to reducing the risk of concerns, particularly cognitive decline.

In addition to being monitored by your doctor, regularly checking your blood pressure can help alert you to possible issues.

“You can check your blood pressure at pharmacies and drug stores that have free blood pressure machines,” Tyler said. “You can also buy a home blood pressure cuff.”