Cases of dementia are rising rapidly among Britain’s ageing population. Protecting against it begins with looking after your heart
There are 900,000 currently living with dementia in the UK and that’s predicted to rise to 1.6 million by 2050. Frightening as the figures undoubtedly are, we all have the power to dramatically reduce our risk – and it begins with looking after our hearts.
A landmark new statement released by the American Heart Association warns that three common cardiovascular diseases – heart failure, atrial fibrillation and coronary heart disease – raise the risk of developing dementia, an umbrella term describing a set of symptoms including difficulties with memory, thinking, problem-solving, judgement or language.
Research has shown that 14 to 81 per cent of patients with heart failure experience some degree of cognitive impairment. People with atrial fibrillation have a 39 per cent increased risk of memory or thinking problems, while those with heart disease have a 27 per cent higher risk of developing dementia. Following a heart attack, up to 50 per cent of patients experience cognitive decline.
Vascular dementia, the second most common form of the disease after Alzheimer’s, is predominantly caused by cardiovascular diseases. These compromise the supply of blood to the brain, damaging or killing brain cells by depriving them of the oxygen and nutrients they need to function.
“Managing heart health from an early age is important to prevent cardiovascular disease and cardiac events, protect brain health and reduce the risk of cognitive decline in later life,” said Fernando D Testai, a professor of neurology at the University of Illinois College of Medicine, in the statement.
“The phrase we use is: ‘What’s good for the heart is good for the brain’,” says Dr Ahmad Khundakar, a senior lecturer in biomedical science at Teesside University, whose specialism is dementia and neuroscience.
“Lifestyle factors play a huge part in heart health, which then has a huge impact on brain health, so if we can modify these factors, we can significantly improve our chances of avoiding dementia.”
Understanding these heart conditions is key to understanding what we need to do. Here, we explain what they are, how they’re linked to brain health, and how we can protect ourselves against them.
Heart failure
Heart failure occurs when the heart cannot pump blood around the body as well as it should. It is caused by damage to the heart, commonly due to high blood pressure or heart disease.
“It leads to a constellation of symptoms,” says Dr Sohail Khan, a consultant interventional cardiologist at The Harborne Hospital in Birmingham. “These include fatigue, breathlessness, particularly after activity, and fluid retention, which leads to puffiness. The fluid builds up in the lungs, so patients often wake up in the night gasping for breath.”
Another side effect is a decreased level of oxygen reaching the brain via blood vessels, and it is this which increases the risk of vascular dementia. “Small holes, or hyperintensities, start appearing in the brain’s white matter – essentially, the cabling,” says Dr Khundakar. “They can impact the circuitry involved in cognitive function and memory, damaging them.”
Alzheimer’s is a disease which begins inside the brain, causing plaques to form which lead to neurodegeneration. However, Dr Khundakar says: “It is thought that a lack of oxygen reaching the brain also exacerbates Alzheimer’s pathology, too.”
Tests for heart failure include a blood test and an electrocardiogram (ECG), which records the electrical activity of the heart. It can be treated with drugs such as angiotensin-converting enzyme (ACE) inhibitors, which relax and open up blood vessels, and beta blockers to slow down the heart rate.
Switching to a healthier diet and exercising can lessen the symptoms, but Dr Khan says: “Unfortunately, once you have heart failure it’s very difficult to reverse, so it’s far better to try to avoid it.”
The single most important way to do this is by ensuring blood pressure is at a healthy level. After 40, it’s a good idea to keep an eye on your metabolic health, by signing up for a free NHS Health Check every five years, which will include a blood pressure and cholesterol check.
“We should all take responsibility for knowing what our numbers are, as these are our modifiable risk factors, which we can do something about,” says Dr Khan. “Don’t assume your cholesterol will be low, as it may not be.”
A report this year by researchers from UCL found that 7 per cent of dementia cases are attributable to high low-density lipoprotein (LDL) or “bad” cholesterol, in midlife. Reducing saturated fats, maintaining a healthy weight, eating a diet rich in vegetables and good fats, taking regular exercise, avoiding smoking and limiting alcohol are vital for lowering cholesterol and blood pressure.
Atrial fibrillation
Atrial fibrillation is a condition which affects 1.4 million people in Britain and causes an irregular and often abnormally fast heart rate. Symptoms include heart palpitations, dizziness and shortness of breath.
It happens when abnormal electrical impulses suddenly start firing in the atria, overriding the heart’s natural pacemaker. Although the cause is not fully understood, “it tends to affect older people, and people with long-term conditions such as heart disease, high blood pressure and obesity”, says Dr Khan.
An irregular heartbeat increases the risk of blood clots forming, which can travel to the brain and cause a stroke. “Major strokes occur when there’s a blockage in a relatively large blood vessel, and that shuts off the oxygen supply to parts of the brain, which affects cognitive function,” says Dr Khundakar.
By Polly Dunbar
