Optimal Cardiovascular Health and a Healthy Brain

Our brains represent who we are and, because we communicate with others via our brains, represent who we are as humanity. Thus, one can argue that optimal brain health should be our highest global and individual priority. Just like plants in a garden need water and food to grow properly, our brains need sufficient hydration and fuel to function well. In some areas of the world, optimal brain health begins first with adequate food and water.

Given adequate food, water and basic medical care, the next key question is how we can provide the best environment for a healthy brain. As detailed in the accompanying American Heart Association/American Stroke Association Presidential Advisory, one can convincingly argue that optimal cardiovascular health is the most important physical, modifiable, and measurable contribution to a healthy brain.¹ The lifetime social environment (family, friends, society and culture) and the individual’s native intelligence, emotional stability, and drive to learn and engage are the most important cognitive contributions to optimal brain health.

While society may not always view brain health as its highest priority, our human biology reflects the priority of brain health as determined by evolution. The brain has the greatest metabolic demand of any organ; its metabolic requirements peak in childhood during which it uses glucose at a rate equivalent to 66% of the body’s resting metabolism and 43% of the body’s daily energy.² The heart and the cerebrovascular tree are responsible for the delivery of glucose and oxygen underlying this high metabolic rate so it is not surprising that cardiovascular health is so critical to optimal brain health. In addition, as outlined in the Presidential Advisory, cerebrovascular regulatory mechanisms ensure that the brain has needed fuel and critical substances. These mechanisms include neurovascular coupling in which focal increases in brain activity are associated with corresponding increases in blood flow to the activated areas,³ cerebrovascular autoregulation that maintains constant blood flow to the brain over a range of arterial pressures,⁴ and a vascular system with extensive collateral pathways and built-in redundancy. This cerebrovascular system is also critical for removal of toxins and wastes that are maximally removed during sleep,^5,6 which is why adequate sleep is also important for optimal brain health. Given the extensive and redundant protective mechanisms for perfusion and drainage of the brain, it is not surprising that dementia and cognitive impairment do not appear until mid or later life for most individuals.

The accompanying Presidential Advisory has three primary messages. First, poor brain health has a large and growing impact on our society, particularly as we age and our cardiovascular health declines with advancing age. Second, we have clear metrics of optimal cardiovascular health in individuals and the population, Life’s Simple 7,⁷ that can measure the effectiveness of efforts to maintain and maximize cardiovascular health at any point in a person’s life. Life’s Simple 7 includes four health related behaviors (non-smoking status; physical activity at goal levels; body mass index <25 kg/m2; and healthy diet consistent with current guidelines) and three health factors (untreated blood pressure <120/<80 mm Hg; untreated total cholesterol <200 mg/dL; and fasting blood glucose <100 mg/dl).

Third, we have good outcomes to measure the loss of brain health, particularly those associated with loss of cardiovascular health: stroke and dementia as primary outcomes, and transient ischemic attack and mild cognitive impairment as secondary and often earlier markers of loss of brain health. Other outcomes using brain imaging such as health of the subcortical white matter, subclinical infarcts, measures of brain connectivity, and amyloid deposition, can help us understand the biologic mechanisms related to both cardiovascular and brain health. Primary and secondary prevention of symptomatic and subclinical brain injury due to cardiovascular disease remains a critical avenue of research in maximizing and maintaining brain health.

Optimal brain health at each time in our lives should be our highest priority. It requires not only efforts to maintain optimal cardiovascular health as described in the Presidential Advisory but also education, a good social environment, adequate nutrition, and basic medical care. Research investments into cardiovascular and brain health by governmental agencies, non-profit foundations such as the American Heart Association, American Stroke Association, and the Alzheimer’s Association, and private philanthropy should reflect this priority.