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 CirculationTrusted Source 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.
Blood pressure levels and dementia diagnoses
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%.
Staying within a target blood pressure range
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.
Determining healthy blood pressure levels
There are two blood pressure measurements: systolic and diastolic. For the study, the researchers focused on systolic blood pressure.
SystolicTrusted Source 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. HealthyTrusted Source blood pressure is considered less than 120/80 mmHg.
High blood pressure — also known as hypertension — is experienced by almost half of adultsTrusted Source 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,” Tyler said.