Feeling woozy when you stand up may be a sign of an increased risk of developing dementia, a new study suggests.

Doctors call this feeling “orthostatic hypotension,” and it occurs when there’s a sudden drop in blood pressure as you stand, explained a team of researchers from the University of California, San Francisco (UCSF).

The researchers found a connection between orthostatic hypotension and later onset of dementia with a drop in systolic blood pressure of at least 15 mm Hg, but not diastolic blood pressure or blood pressure overall. Systolic blood pressure is the top number in a blood pressure reading.

The finding suggests that “people’s blood pressure when they move from sitting to standing should be monitored,” UCSF researcher Dr. Laure Rouch said in a news release from the American Academy of Neurology. “It’s possible that controlling these blood pressure drops could be a promising way to help preserve people’s thinking and memory skills as they age.”

Rouch cautioned that this study couldn’t prove that orthostatic hypotension causes dementia, only that there appears to be an association.

In the study, her team tracked the medical history of more than 2,100 people who averaged 73 years of age and did not have dementia at the beginning of the study. Over the next 12 years, 22% of these individuals developed dementia.

Those with systolic orthostatic hypotension were nearly 40% more likely to develop dementia than those who didn’t have the condition, Rouch’s group reported recently in the journal Neurology.

Put another way, the study found that 26% of participants with systolic orthostatic hypotension developed dementia, compared with 21% of those who didn’t have the condition.

After adjusting for certain health factors — such as diabetes, smoking and alcohol use — those with systolic orthostatic hypotension still had 37% higher odds of developing dementia, the research showed. And people whose systolic blood pressure changed the most were more likely to develop dementia than people whose readings were more stable.

Among those whose systolic pressure varied, 24% with the most fluctuation developed dementia, compared with 19% of those with the least fluctuation, the researchers found. Those whose systolic pressure varied the most were 35% more likely to develop dementia than those whose pressure was more stable, the findings showed.

How might dizziness upon standing impact your odds for dementia? Cardiologist Dr. Guy Mintz has some theories.

“The mechanism of this association is unknown, but it is reasonable to suspect that multiple low blood pressure ‘insults’ to the brain could cause cumulative damage,” said Mintz, who directs cardiovascular health at Northwell Health’s Sandra Atlas Bass Heart Hospital in Manhasset, N.Y. “Other mechanisms postulated involve direct damage to the blood vessels or progressive stiffness of the arteries.”

Whatever the background causes, Mintz believes that “doctors should be aware of this relationship, because it represents an opportunity to help older patients on multiple hypertensive drugs that have a change in the systolic pressure with positional changes. Older patients are usually on multiple medications for high blood pressure and this simple positional maneuver can identify patients at increased risk for dementia, and the medications could be fine-tuned.”

More information

For more on dementia, head to the Alzheimer’s Association.