Protecting your heart not only keeps your body healthy, but also protects your brain from cognitive decline. Learn how early heart health interventions can help prevent dementia and improve brain function.
Judgement: Heart failure, atrial fibrillation and coronary heart disease linked to cognitive impairment. Image credits: Jo Panuwat D / Shutterstock
In a recent review published in the journal Myocardial infarctiona group of authors explored the mechanisms linking common heart diseases to cognitive impairment and highlighted the potential to reduce neurological risk by improving cardiovascular health.
Background
The heart and brain are closely linked, with the heart supplying essential oxygen and nutrients to the brain, while the brain controls cardiac function through the autonomic nervous system. This relationship is also influenced by complex mechanisms such as neurohormonal activation and systemic inflammation, both of which can accelerate cognitive decline in the presence of heart disease.
Research shows that adverse heart conditions, such as increased left ventricular wall thickness, are associated with brain abnormalities, such as changes in white matter (WM) structure. Recent findings also point to the prevalence of silent cerebral infarctions, which occur without noticeable symptoms but contribute to long-term cognitive decline.
Cardiovascular disease (CVD) and vascular risk factors (VRFs) contribute to cognitive decline, brain injury and dementia. Addressing VRFs early in life, for example by controlling blood pressure and cholesterol, can help reduce these risks. Further research is essential to unravel the complex mechanisms of these associations and develop effective prevention and treatment approaches.
Heart and brain health: a synergistic relationship
The heart and brain work in a dynamic partnership. The brain depends on the heart for a constant supply of oxygen and nutrients, while the heart depends on the brain for regulation through autonomic control. This mutual interaction, when disrupted by disease, can lead to significant health complications.
Genetic and phenotypic factors often affect both organs, and damage to one can affect the other. For example, changes in heart structure, such as an increase in left ventricular wall thickness, have been associated with brain abnormalities, including a reduction in WM integrity. These abnormalities, often detectable via imaging, signal the early onset of cognitive impairment in patients with cardiovascular disease.
The impact of cardiovascular disease on brain health
HF and cognitive decline
HF is a complex condition in which the heart is unable to pump blood efficiently, leading to poor circulation and reduced oxygenation of the brain.
Studies have shown that HF is often associated with cognitive decline, especially in older adults. In fact, up to 43% of patients with HF exhibit some form of cognitive impairment. Cognitive functions such as memory, attention and executive functions are often impaired in patients with HF. Decreased cardiac output and cerebral hypoperfusion are thought to contribute to this cognitive decline, as the brain receives less blood flow and oxygen.
Emerging research suggests that the relationship between HF and brain health extends beyond oxygen deprivation. For example, HF is associated with increased inflammation and neurohormonal activation, both of which are linked to neurodegenerative processes.
Furthermore, structural changes in the brain, such as WM hyperintensities and silent brain infarcts, are more common in individuals with HF.
Atrial fibrillation (AF) and brain health
AF is the most common cardiac arrhythmia, characterized by an irregular and often rapid heartbeat. AF significantly increases the risk of stroke, which can directly lead to cognitive impairment. But even in the absence of stroke, AF is associated with an increased risk of dementia and other forms of cognitive decline. Recent studies suggest that this increased risk may be due to silent microemboli, which impair cerebral blood flow.
Furthermore, AF has been associated with an increased burden of WM lesions and other markers of small vessel disease, which are associated with cognitive decline. Inflammatory processes related to AF may also contribute to neuronal damage and the development of neurodegenerative disorders such as Alzheimer’s disease.
Coronary heart disease (CHD) and cognitive impairment
CHD occurs when the arteries that supply blood to the heart become narrowed or blocked, leading to heart attacks and other cardiovascular complications.
CHD is another major contributor to cognitive decline. The shared risk factors for CHD, such as high blood pressure, diabetes and high cholesterol, are also risk factors for brain diseases such as stroke and dementia. These risk factors not only accelerate systemic inflammation, but also compromise the blood-brain barrier, allowing harmful substances to enter the brain and cause neuronal damage.
In patients with CHD, cognitive impairment is often observed after acute coronary events such as myocardial infarction (heart attack). Decreased blood flow to the brain, silent cerebral infarctions, and increased WM lesions are some of the mechanisms by which CHD affects brain health.
Interestingly, the relationship between CHD and cognitive decline is bidirectional, with cognitive decline also increasing the risk of heart disease. This suggests that integrated treatment approaches, targeting both the heart and brain, may provide better long-term outcomes.
Mechanisms linking heart disease and cognitive impairment
Heart disease contributes to cognitive impairment through several mechanisms. Systemic inflammation from cardiovascular disease causes neuroinflammation, which damages brain cells.
Cerebral hypoperfusion, caused by reduced blood flow, leads to WM damage and cortical thinning. Neurohormonal activation in HF, involving hormones such as angiotensin II and catecholamines, affects both cardiac function and cognitive processes, potentially accelerating brain degeneration. Furthermore, disruptions in autonomic control may exacerbate the progression of cognitive symptoms.
Prospects for prevention and treatment
Given the strong link between cardiovascular health and cognitive function, early intervention and prevention strategies targeting heart health may have beneficial effects on brain health.
Controlling vascular risk factors, such as hypertension, diabetes, and hypercholesterolemia, is critical in reducing the risk of both cardiovascular and neurodegenerative diseases. Multi-domain interventions combining diet, exercise, and cognitive training have shown promising results in preserving cognitive function.
In addition, treatments for HF, AF, and CHD, including medications, lifestyle changes, and surgical procedures, can also help preserve cognitive function. Precision medicine approaches could further optimize treatment strategies, allowing individual risk factors to be addressed more effectively.
Conclusions
In summary, the study concludes that heart diseases, including HF, AF and CHD, are strongly linked to cognitive impairment through shared biological mechanisms such as inflammation, cerebral hypoperfusion, neurohormonal activation and small vessel disease.
These findings highlight the interdependence of heart and brain health. By prioritizing early prevention strategies and addressing vascular risk factors at an earlier age, it may be possible to attenuate cognitive decline and neurodegeneration.