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Keeping blood pressure in the target range may be more important for those at risk of developing dementia. Eddie Pearson/Stocksy
  • According to the American Heart Association, almost half of U.S. adults have high blood pressure, and only 1 in 5 have their condition under adequate control.
  • New research shows that the longer a person’s blood pressure remains under control, the lower their risk for cognitive decline or dementia.
  • The researchers believe this study is the first to investigate the relationship between the time blood pressure levels remain within a target range and the associated risk.
  • Experts agree that lifestyle changes, including regular exercise and a healthy diet, sometimes with the support of medication, can help maintain healthy blood pressure levels.

Although blood pressure fluctuates over time, even throughout the day, uncontrolled high blood pressure (hypertension) is when a person’s blood pressure remains outside a healthy target range for extended periods.

Uncontrolled high blood pressure can result in a greater risk for cognitive decline or dementia as well as cardiovascular disease. It is therefore essential that uncontrolled hypertension is identified and treated through lifestyle changes and/or medication. Medicines used to treat blood pressure are called antihypertensives.

The new research, published in Circulation, suggests that optimal heart and brain health is best achieved when a person’s systolic blood pressure (the upper number) is kept consistently under control, rather than when it regularly fluctuates.

Researchers analyzed data for 8,415 people in the Systolic Blood Pressure Intervention Trial, or SPRINT, which compared intensive treatment to standard treatment of systolic blood pressure among people with hypertension.

Researchers recorded the participants’ blood pressure at the beginning of the study and then once a month for the first three months of follow-up. They determined time in the target range using the first three months of blood pressure measurements.

Typical blood pressure is defined as a systolic reading of less than 120 mmHg and a diastolic reading (the lower number) of less than 80.

In the study, the researchers defined the target range for intensive control as 110 to 130 mmHg and the standard control target range as 120 to 140 mmHg.

At the start of the study, the researchers assessed the cognitive status of participants to ensure they were free of cognitive decline or dementia.

Participants underwent cognitive status assessments two more times during the follow-up period using trained examiners to determine if participants had cognitive decline or probable dementia.

After a five-year follow period, the analysis showed that people who maintained systolic blood pressure levels within the target range were less likely to be diagnosed with probable dementia.

Five experts, who were not involved in this research, explained the findings and implications for patients to Medical News Today.

Dr. Anjali N Patel, DO, a fellowship-trained cognitive neurologist at the Atlantic Neuroscience Institute at Overlook Medical Center said that the SPRINT trial “evaluated older adults with hypertension and one other cardiovascular risk factor such as chronic kidney disease, to determine if lowering the systolic blood pressure to 120mm Hg instead of 140mm Hg provided any benefits.”

“Overall, researchers found the participants had fewer heart attacks, strokes, and cardiac deaths. In reviewing the data further, researchers found lowering the target range of the blood pressure for [a] prolonged period was associated with a lower risk of probable dementia,” she told MNT.

However, Dr. Patel pointed out that in those with atrial fibrillation and hypertension, a lower target blood pressure range may increase “the risk of probable dementia.”

She said that, for people with hypertension, primary care physicians or cardiologists should work as a team to lay out the best goals of care tailored to the individual.

“This is an important study that shows certain patients with cardiovascular risk factors can benefit from more aggressive control of their blood pressure. For example, in individuals with [a] risk of developing a dementia disorder better management of their blood pressure may be beneficial.”
— Dr. Anjali N Patel

Meanwhile, Dr. Richard Marottoli, of the Adler Geriatric Assessment Centre, part of Yale Medicine, described the findings as “potentially intriguing.”

“These are encouraging findings —vascular risk factors play a role in a number of dementias and having an option or goal for management gives individuals and clinicians another tool that is under their control to prevent the onset or limit or slow progression of cognitive changes,” he told MNT.

Dr. Don Pham, a cardiologist at the Memorial Hermann Southeast Hospital said that the link between blood pressure and dementia risk was already established by previous research.

He said the latest data shows that the greater the time spent in targeted blood ranges, the lower the risk of probable dementia was.

“In general, hypertension has been well studied to be a risk factor for cognitive impairment, vascular dementia, and stroke though many questions remain in this area with limited data. This study suggests that time in a systolic blood pressure range should be considered as an additional modifiable risk factor to lower the likelihood [of] probable dementia.
— Dr. Don Pham

Dr. Rigved V. Tadwalkar, a board certified cardiologist at Providence Saint John’s Health Center, found the new research to be “quite informative, answering a clinical question that we have had for some time.”

“A recent metric that has been of interest, due to its applicability in clinical practice, is time in target range. This metric is attractive because it accounts for how blood pressure values may fluctuate over time,” he told MNT.

“It is not surprising to see that those who achieved blood pressure values in the target range for a greater period of time experienced less dementia. We know that high blood pressure can damage blood vessels over time, causing arteriosclerosis and atherosclerosis. When this occurs in the arteries of the brain, the result is diminished oxygen and nutrient delivery chronically to the brain parenchyma itself, causing dysfunction.”

— Dr Rigved V. Tadwalkar

Dr. Sandra Narayanan, board certified vascular neurologist and neurointerventional surgeon at Pacific Stroke & Neurovascular Center, noted that “time to target range (TTR), as opposed to absolute measurement of Systolic Blood Pressure (SBP) is a more useful predictor of dementia risk.”

In this study, “time to target range did not predict the risk of developing mild cognitive impairment, however,” she added.

When asked how patients can manage and monitor their blood pressure levels, Dr. Patel highlighted that “we need to be mindful regarding using these blood pressure recommendations for all patients.”

“The research study, for example, did not include those with diabetes and was mostly compromised of men. Risks and benefits of adding additional medication to further lower the blood pressure should be reviewed on a case-by-case basis,” he said.

Dr. Tadwalkar noted the importance of lifestyle factors, telling MNT that his “best advice is to vary the types of activity one does.”

“By performing a wide mix of exercises or activities, including those that are cardio-focused, weight-bearing in nature, balance or posture-related, mentally demanding, and those that are concerned with spiritual and emotional-centeredness, one can truly attain total body benefits. This includes less stress, greater mental clarity, better body mass index, lower cholesterol, improved glucose tolerance, and of course, more ideal blood pressure values.”
— Dr. Rigved V. Tadwalkar

Other aspects certainly play a role, including:

  • a healthy diet that emphasizes whole grains, lean or vegetarian sources of protein, healthy fats, as well as fruits and vegetables
  • quitting smoking
  • minimizing alcohol use
  • ensuring adequate amounts of sleep

Dr. Patel agreed, saying “the first line of treatment should include lifestyle modifications such as exercise, weight loss, diet, and tobacco use.”

But crucially, she said, “it is important to discuss your cardiovascular risk factors and appropriate management with your primary care physician or cardiologist.”