Ed note: This article is an adapted extract from Increase Your Brainability and Reduce Your Risk of Dementia.
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, 80 per cent of premature heart disease and stroke is preventable. Physical activity (“the miracle cure”), not smoking, maintaining a healthy weight and a Mediterranean diet are the 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 640 kilometres of blood vessels in the brain and they cover a surface area the size of a tennis court. While the brain comprises only about 2.5 per cent of the body’s weight, it receives 15 per cent 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 that 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 for furring up 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.
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 to 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. People over the age of 40 should have their blood pressure checked regularly at the very least every couple of years. Once high blood pressure is diagnosed, it can be treated with lifestyle modifications as well as using drugs.
Type 2 diabetes (non-insulin dependent) is completely different from Type 1 (insulin-dependent), which is a disease of unknown cause. Type 2 diabetes can be prevented and effectively managed. Type 2 diabetes may directly damage the brain, but its main negative impact is increasing the risk of atherosclerosis. 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 its dangers, for example those that lurk beside every checkout counter 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. 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 in which the heart beats irregularly, allowing small clots to form that 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 and smoking can also trigger atrial fibrillation. If you have atrial fibrillation, you will usually need treatment to control the condition as well as treatment to reduce your risk of stroke. This may involve taking drugs called antiarrhythmics that act by making your heart rhythm 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 (TIA’s) 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.
But remember that it’s never too late. Studies have shown that physical activity, not smoking, maintaining a healthy weight and a Mediterranean diet can have a positive effect on your health no matter when you start.