While acting with our heart or our head may seem like two completely different faculties, European researchers are finding our brain and our heart may be more linked than we previously thought. In a new study published in the journal Neurology, researchers from Leiden University Medical Center found that a test of executive function, a higher mode of thinking known for reasoning, problem solving, and planning, could predict your likelihood of heart attack and stroke.

For a while now, scientists have known that cognitive decline could also result in problems with your heart and vascular system. Previous research found that when looking into the brains of patients with dementia or cognitive impairment, doctors were able to find a number of brain lesions and microbleeds, indicating underlying vascular diseases — thus implying that a heart attack or stroke was soon to come. But these findings were mostly consistent with executive function, as opposed to other brain functions like memory.

“From the previous literature we know that exposure to cardiovascular risk factors is a risk factor for cognitive impairment, particularly impairments in executive function,” lead author Dr. Benham Sabayan, of Leiden University Medical Center, told Medical Daily.

Looking into this link further, researchers examined how a drop in executive function could possibly correlate to impending heart problems. For the study, they recruited 3,926 people whose average age was 75, and who came from either the UK or the Netherlands. Each had a preexisting history of heart disease or a predisposition for cardiovascular disease due to high blood pressure, smoking, or diabetes. The researchers made sure their participants did not suffer from dementia.

They then gave participants four different tests to evaluate their higher-level thinking skills, and subsequently categorized them based on whether they got low, medium, or high test scores. After the tests, they tracked the health of these participants for about three years to see if any suffered from stroke or heart attack. At the end of the time, they counted 375 heart attacks and 155 strokes among the group, or an average of 31 heart attacks per 1,000 people and 12 strokes per 1,000 people.

As expected, those who were at the lowest end of executive function were 85 percent more likely to have a heart attack than those with high thinking capabilities. The total number of “low” scorers who suffered a heart attack was 176 out of 1,309 people, compared to 93 out of 1,308 “high” scorers. Strokes were also more common among people with low scores, representing a 51 percent greater likelihood than those who scored well. Overall, 69 strokes occurred in the low-scoring group as opposed to 48 strokes in the high-scoring group.

While these findings are fascinating, past studies have also produced interesting insight into the heart-brain connection. Research from Johns Hopkins University School of Medicine found that a single protein, known as brain-derived neurotrophic factor (BDNF) is responsible for both the growth and livelihood of nerve cells, along with maintaining the heart’s strength and rhythm in mice. They also discovered that while malfunctions of BDNF in mice led to nervous system issues, they also translated into heart abnormalities.

As to why this link exists, Dr. Sabayan believes that impaired cognitive function could result from a problem getting blood into the brain. “Worse brain functioning in particular in executive function could reflect disease of the brain vascular supply, which in turn would predict, as it did, a higher likelihood of stroke,” Sabayan said in a recent press release. “And, since blood vessel disease in the brain is closely related to blood vessel disease in the heart, that's why low test scores also predicted a greater risk of heart attacks. We acknowledge that even though the results were statistically significant, the risks were small."

When asked how doctors should proceed in light of their findings, Sabayan told Medical Daily that they should be aware this link exists and act accordingly. “Overall, our findings highlight that older subjects with lower executive function might need closer attention in terms of cardiovascular risk management,” he said. “Future studies are needed to introduce specific interventions proper for older adults with lower cognitive function.”

Source: Rostamian S, Sabayan B, de Craen A, et al. Executive function, but not memory, associates with incident coronary heart disease and stroke. Neurology. 2015.

Paolocci N, Feng N, Huke S, et al. PNAS. 2015.