Heart and brain health are two of the most important areas for healthy aging, and previous studies have shown that there’s a direct relationship between the efficiencies of these systems. But a new study has outlined exactly what that link is and why it matters for preventing cognitive decline.

The study, conducted by researchers at the Max Planck Institute for Human Cognitive and Brain Sciences and the Leipzig Heart Clinic, found that the lack of oxygen to the brain as a result of a weak heart can cause a decline in the density of gray matter.

Gray matter is composed of neurons, and the majority of it in the brain is part of the cerebral cortex, which manages “higher mental capabilities” like language, speech, creativity, and decision making.

“The weaker the heart, the lower the density of the grey matter,” said Matthias Schroeter, Ph.D., the head of the Cognitive Neuropsychiatry research group at the Max Planck Institute in Leipzig.

The study specifically focused on the impact of heart failure on brain health, and the impact of the damage it can do on the heart to the brain long term. They do note that they only considered the concrete impact on the density of gray matter and that further studies would be necessary to assess the actual cognitive impact.

In the study of 80 participants, researchers measured the amount of blood the heart pumped with each beat and tracked the concentration of a hormone in the blood, which is used as a marker for heart insufficiency. Paired with MRI scans of the brain, they were able to find this link between brain and heart health.

“In the case of heart failure,” said Schroeter, “it’s important to also take into account that the brain structure can be damaged.” Naturally, treating the damage to the heart as a result of heart failure is the priority; however, the results of this study indicate that consideration should be given to how it affects the brain.

Given gray matter’s role in brain function, is it an important component in some of the cognitive diseases that sometimes face aging people. “A decline of grey matter,” said Schroeter, “could make it more likely that someone would develop Alzheimer’s disease.”

In addition to heart failure, high blood pressure has also been linked to a decline in gray matter in previous studies. Given the strong link between these two important systems, planning for boosting their health is an important part of maintaining health. If you’re looking to boost the health of your heart and your brain, the Mediterranean diethas been linked to benefits for memory and heart health.