A study appearing in Journal of Gerontology: Psychological Sciences suggests that sudden surges in blood pressure could prevent seniors with chronic hypertension from thinking clearly.

More exactly, researchers found that older people with hypertension suffered a drop in IQ and the ability to recall simple information on days when their blood pressure was particularly high.

The finding is another reason for people with high blood pressure to get the condition under control. High blood pressure is a serious condition that can lead to coronary heart disease, heart failure, stroke, kidney failure and other serious health problems. Besides obesity, there are other factors contributing to the condition including a family history of high blood pressure, smoking, alcohol use, excessive salt in diet and a sedentary lifestyle.

The Centers for Disease Control and Prevention estimates that about one in four adults suffers from high blood pressure. The bad part is that the condition has no visible symptoms and that’s why most people are unaware that they have it, exposing themselves to serious risks. The elderly are particularly at risk.

Healthy adults should have a blood pressure of 120/80 millimeters of mercury (mmHg) or better, according to specialists. A person suffers from hypertension when its blood pressure is 140/90 or higher.

The new study led by North Carolina State University psychology professor Jason Allaire tracked 36 people, average age 73, having each of them take blood pressure reading and take a series of cognitive test twice daily for 60 days. The tests assessed things like thinking abilities, pattern recognition and problem solving.

The results of the tests showed a direct correlation between the times when their blood pressure was high and lower “cognitive” ability. The higher the blood pressure the more mistakes the seniors made.

“This finding suggests that if you have high blood pressure that is not controlled, your cognitive abilities are going to decline faster as you get older,” Allaire said.

Participants in the study whose average blood pressure was low or normal saw no change in their cognitive functioning –even when their blood pressure shot up.

Previous studies have shown that simply having high blood pressure is related to worse cognitive performance in the elderly, but none of them evaluated the impact of blood pressure spikes. Several studies have found a link between high blood pressure and dementia, which is marked by a loss of memory and other cognitive abilities, including the ability to speak, identify objects or think abstractly. No further than July, a study found that treating high blood pressure in the very elderly may help reduce their risk of developing dementia.

“If you have blood pressure that wildly fluctuates and you have high blood pressure, you might be in double trouble for poorer cognitive functioning,” Allaire said.