The Connection Between Heart Disease and Brain Health

Experts discuss how avoiding heart disease can also boost brain health

Change is hard. Maybe that’s why so many of us continue to line up for fast food, and spend too much time lounging on the couch rather than going for a walk or engaging in some other form of actual movement. Meanwhile, health professionals continue to warn of the dangers of heart disease, and rightly so. After all, cardiovascular disease is the number one killer of men and women worldwide.
But even though most of us are fully aware of what we should do to keep our heart healthy, many don’t realize that the factors that make us more likely to develop heart disease — such as obesity, diabetes, inactivity and smoking — also raise our risk of Alzheimer’s disease and other forms of dementia.

In addition to risk factors that are shared between heart and brain disease, “there are several types of heart disease that potentially affect the brain,” says Paul F. Boffetti, MD, FACC, director of interventional cardiology at Foundation Cardiology at Southern New Hampshire Medical Center in Nashua. People who have an irregular heartbeat condition such as arrhythmia or atrial fibrillation, for example, face an increased risk of developing dementia.

Some of the factors that make us more likely to have brain as well as heart disease are beyond our control, such as age and genetics. But research offers overwhelming evidence that we can tilt the odds of staying healthy in our favor through the lifestyle choices we make each day. Many of those choices help safeguard the condition of our blood vessels — which are crucial, of course, to the heart, but also to the brain.

Cardiovascular disease “affects the vascular system, and the brain is a vascular organ,” Boffetti says, which means it is vulnerable to trouble that occurs in the heart, and in the blood vessels. The same atherosclerosis that gradually and quietly over the years gums up arteries near the heart with plaque, for example, can also impede blood flow in the vessels that feed the brain, and possibly lead to a stroke and cognitive impairment. “Atherosclerosis is a systemic disease that can affect many organs, but the heart and the brain are the two most commonly affected,” Boffetti says. “Heart disease and stroke correlate because frequently it’s a similar process that causes the heart attack or the stroke to occur.”

People who experience a stroke face a heightened risk of vascular dementia, the second most common form of dementia after Alzheimer’s disease. Stroke damages the vessels that supply blood to the brain, killing brain cells by depriving them of vital blood and oxygen, and weakening the brain’s ability to concentrate, analyze, remember or perform other cognitive tasks.

Brain function can also be impaired by what are sometimes described as “silent strokes,” which can be influenced by some of the same factors that lead to heart disease. “Silent strokes are when you have a lack of blood flow to a certain part of the brain but do not have overt symptoms,” says Syed Peeran, MD, a vascular surgeon at Appledore Medical Group Coastal Cardiothoracic & Vascular Surgery, based out of Portsmouth Regional Hospital. While we might expect to be able to recognize what we think of as a typical stroke by observing a stricken individual’s suddenly slurred speech, half-drooped face or paralysis on one side of the body, someone who experiences a silent stroke might appear to only have difficulty finding the right word while speaking, Peeran says, or might experience a tingling or numbness in one hand.

Because silent strokes are subtle, people don’t always realize that they’ve had one. In many instances, they or their loved ones attribute any noticeable symptoms to something else, such as aging or simple forgetfulness.

A silent stroke causes less profound damage to brain tissue than a large, acute stroke does, but the damage it causes is permanent — and a silent stroke can be a harbinger that a more prominent stroke is likely to occur. “It can be a warning sign that a pending stroke is about to happen,” Peeran says, stressing that such an omen should be taken very seriously.

Ultimately, however, the best approach to maintaining brain as well as heart health is prevention. And unfortunately, the characteristics that are linked with both heart and brain disease are all too common in the US population, Boffetti says, due to the typical American lifestyle. More than a third of American adults are now considered obese, for example, and high blood pressure and diabetes, which often go hand in hand with obesity, make us more likely to develop both heart and brain disease, thereby likely raising our chances of experiencing earlier onset dementia, Boffetti says, as well as dementia in general.

If you want to do what you can to minimize your chances of developing heart and brain disease, make smart lifestyle choices that include getting regular exercise, managing blood pressure, cholesterol and blood sugar and not smoking. Doing so, Peeran says, will help steer you away from factors that “contribute to cardiovascular disease and poor health all the way around,” and that definitely don’t do your brain any good. “Poor cardiac function and cardiac disease,” Peeran says, “can only be detrimental to brain function.”

The Danger of “Silent Strokes”

Factors that increase our risk of developing heart disease can also make it more likely that we will develop dementia, at least in part by raising our likelihood of having small strokes known as “silent strokes.”

During a typical stroke, a blood clot abruptly blocks blood flow to a specific region of the brain, resulting in an acute change in cognitive function or physical ability, says Paul F. Boffetti, MD, FACC, director of interventional cardiology at Foundation Cardiology at Southern New Hampshire Medical Center in Nashua. In contrast, a silent stroke is more diffuse, and occurs in the smaller vessels of the brain, “so it’s not like all of a sudden a third of the brain has no blood flow,” Boffetti explains. “It’s more like all throughout the brain there is small vessel disease that leads to damage of the functioning brain cells — the neurons — and that can cause cognitive decline.”

These mini or silent strokes gradually erode brain function. “They are silent in the sense that you can’t identify the moment in which the stroke occurred,” Boffetti says, unlike a full-blown stroke, which leads to “an obvious, significant change in the ability to do something,” such as speaking or moving.

People can have more than one silent stroke, and don’t always realize that they’ve had one. Family members might notice a subtle change in a loved one who has had a silent stroke, and chalk it up to age or forgetfulness. “But it’s more than that,” Boffetti says. “There has been damage to the brain. The brain will shrink a little bit as you age anyway, but this is beyond the normal aging process of the brain.”

And the damage wrought by smaller strokes is lasting. “Once you’ve lost brain tissue,” Boffetti says, “it doesn’t regrow.”

Reduce your risk

Safeguard the health of your brain and your heart by reducing your chances of developing brain or heart disease in the first place. The following are among the most crucial steps you can take to create a healthful lifestyle for yourself, as recommended by the American Heart Association:

• Get plenty of physical activity
• Eat a balanced diet that includes enough fruit, vegetables and whole grains. Choose low-fat dairy, lean protein and fish over foods that contain saturated fats, and avoid “empty calorie” items such as soda, candy and pastries
• Maintain a proper body weight
• Do not smoke
• Manage your blood pressure, blood sugar and cholesterol