Heart disease occurs when the blood vessels that supply blood to the heart become narrowed. A similar mechanism occurs in strokes and vascular dementia, where narrowing of the blood vessels reduces blood flow to the brain causing disease.
These diseases are extremely common. Every five minutes, heart disease, stroke and related conditions take a life in Canada. However, eighty percent of premature heart disease and stroke is preventable. Physical activity (the miracle cure), not smoking, maintaining a healthy weight and a Mediterranean diet are main lifestyles that prevent heart disease. These interventions also prevent brain disease by keeping the oxygen supply to your brain plentiful.
Maintenance of healthy blood pressure is important, especially in the blood vessels transporting blood to the brain. There are as many as 400 miles of blood vessels in the brain, and they cover a surface area the size of a tennis court. While the brain comprises only about two and a half percent of the body’s weight, it receives almost 15 percent of the blood flow from the heart, and uses as much as a quarter of the body’s total oxygen consumption. Any reduction or interruption of this flow can cause strokes or mini strokes, which damage brain tissue and contribute to dementia.
Just as the pipes of the hot water system get furred up, so too do our arteries. The medical term is atherosclerosis. Blockage of a large artery results in stroke with noticeable muscular weakness, but blockage of smaller blood vessels can lead to many tiny strokes, causing the death of tiny bits of brain tissue. If enough of these smaller strokes occur, vascular dementia can result.
There are five preventable and treatable health conditions that impede oxygen reaching your brain. Healthy arteries are flexible, strong, and elastic. Their inner lining is smooth so that blood flows freely, supplying vital organs and tissues with adequate nutrients and oxygen. However, high blood pressure, type 2 diabetes, high cholesterol, atrial fibrillation and mini-strokes all damage blood vessels, thus impeding the flow of blood to the brain.
If you have high blood pressure, the increased pressure of blood flowing through your arteries gradually can cause a variety of problems, including damage to the cells of your arteries’ inner lining. That predisposes a series of events that make artery walls thick and stiff, a disease called arteriosclerosis, or hardening of the arteries. Fats from your diet enter your bloodstream, pass through the damaged cells, and collect in clumps on the vessel walls, that is, atherosclerosis. The only way to know whether you have high blood pressure is to have it measured. Anyone over the age of 40 should have it checked regularly, at the very least every couple of years. Once high blood pressure is diagnosed, it can be treated with life-style modifications as well as using drugs.
Type 2 diabetes (non-insulin dependent) is completely different from type 1 diabetes (insulin dependent) which is a disease of unknown cause. Type 2 diabetes can be prevented and very effectively managed. It may directly damage the brain, but its main negative impact is increasing the risk of atherosclerosis, the porridge-like material that builds up in the walls of arteries. Atherosclerosis blocks blood supply to the brain either slowly or quickly when a clot forms. Preventing and managing type 2 diabetes is an important way of preventing this. Medications are effective, but increasing physical activity and decreasing energy intake are even more important. These lifestyle interventions can help control and even cure type 2 diabetes. The modern environment can make it difficult to implement these interventions, therefore awareness is needed of the dangers of the modern environment, for example those that lurk beside every checkout where calorie rich food packages are stacked high.
Although cholesterol is essential for all body tissues to function properly, it is also a key component in fatty deposits and plaque that build up in arteries. Total blood cholesterol levels greater or equal to 5.2 mmol/L are considered a risk factor for cardiovascular disease. Cholesterol levels are lowered by taking statins, which also reduce the risk of atherosclerosis and therefore the risk of stroke, heart attacks and other cardiovascular diseases.
Atrial fibrillation is a condition where the heart beats irregularly, allowing small clots to form, which can then break off and be carried in the blood stream toward the brain, potentially resulting in strokes. It is the result of a variety of causes, including high blood pressure and damage to the heart through arteriosclerosis or hardening of the arteries. Check your own pulse regularly. Atrial fibrillation tends to occur more frequently when we grow older and have high blood pressure.
Some medical conditions also increase your chances of developing it, including heart problems such as coronary heart disease, or disease of your heart’s valves. It can also be caused by other conditions, including an overactive thyroid gland, lung infections like pneumonia, or a blood clot in the lung (pulmonary embolism). Drinking too much alcohol or caffeine, taking illegal drugs, such as cocaine or amphetamines, or smoking can also trigger atrial fibrillation, which usually requires treatment to control the condition, as well as treatment to reduce your risk of stroke. This may involve taking drugs called anti-arrythmics, which act by treating your heart rhythm, making it more regular as well as slowing your heart rate. It is likely you will also be given other drugs, called anticoagulants, to reduce the chances of developing small clots.
Silent strokes are small strokes that affect parts of the brain that often go unnoticed. Mini strokes or transient ischaemic attacks (TIAs) occur when there is a temporary drop in the blood supply to the brain, leading to temporary stroke-like symptoms. Most of them are caused by clots blocking the blood vessels (ischemic strokes) and in other cases, the damaged blood vessel walls leak and cause a bleed in the brain (hemorrhagic strokes). As with the previously mentioned health conditions, TIAs can be prevented by physical activity, not smoking, not being overweight and a Mediterranean diet.
It’s never too late. Studies show that physical activity (the miracle cure), not smoking, maintaining a healthy weight and a Mediterranean diet can have a positive effect on your health, no matter when you start.
This article is an adapted extract from Increase your Brainability—and Reduce your Risk of Dementia eBook: Alessi, Charles, Chambers, Larry W., Gray, Muir: Amazon.ca: Kindle Store
Larry Chambers is a research director at the Michael G. DeGroote School of Medicine, Niagara Regional Campus, and Professor Emeritus of the Department of Health Research Methods, Evidence, and Impact, Faculty of Health Sciences at McMaster University.
Madeleine Smith is a medical student at the Michael G. DeGroote School of Medicine, Niagara Regional Campus, McMaster University.