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Look after the blood vessels in your brain

Many of us won’t have heard of ‘small vessel disease’ but it’s associated with loss of thinking skills, stroke and dementia, so we need to know more. Professor Joanna Wardlaw of the University of Edinburgh, as part of our Staying Sharp series, shines a light on the evidence.

My advice

  • Lead a healthy lifestyle: keep your weight down, take regular exercise, avoid smoking and eat a healthy diet without adding salt.
  • Get your blood pressure and blood sugar checked regularly, and if you think you may have high blood pressure or symptoms of diabetes.
  • The brain and body are very closely connected, so improvements in your general health are likely to improve your brain health.

The hungry brain

The brain is very energy-hungry. At rest, it uses about as much energy as a nightlight (about 20 watts), but the energy demand rises rapidly when the brain is busy. The energy it uses is glucose. The brain also needs oxygen to do its work, and it produces waste. 

Blood delivers glucose and oxygen to the brain, and also removes waste products. It circulates through the brain via a complex network of blood vessels. The further and deeper into the brain the network penetrates, the smaller the blood vessels become. At their smallest, they are tiny capillaries known as small vessels. Altogether, the brain has about 400 miles of small vessels.

If there is not enough oxygen and food getting into the brain, and rubbish is not being removed as efficiently as it should, then damage can occur.

Brain fact

1 to 1.5 litres of blood go through the brain every minute.

Small vessel disease

In some people, the small vessels become damaged. This is known as small vessel disease. It reduces blood flow, so the supply of energy and oxygen to the brain and the removal of waste become less efficient. This, in turn, leads to damage to the brain itself. 

White matter scars in the brain

As people get older, it is common to find that the brain develops little scars. They look like white dots or patches in brain scans. They are like tiny injuries and mainly affect the brain’s white matter – the wiring connections (axons) between the brain cells (neurons).

The little scars used to be thought of as an inevitable consequence of ageing, like wrinkles on the skin or hair going grey. However, we now know that they are not a natural part of ageing.

In fact, having more little scars is a sign of serious damage. They affect the ability to think clearly and quickly. They can also lead to decline in mobility and mood. If severe, they can lead to dementia and stroke.

Making the connection

Research has found that the little scars are caused by small vessel disease and that the more scars we have, the higher the risk of the problems associated with them.

Therefore, if we address the causes of small vessel disease, we will be reducing the risk of developing potentially damaging little scars in the brain, in turn protecting our brain health and thinking skills.

Fast fact

Small vessel disease is the most common cause of vascular dementia, which is the second most common form of dementia after Alzheimer’s disease.

Risk factors for small vessel disease include high blood pressure, smoking, diabetes, too much fat in the blood, lack of exercise and some dietary factors like too much salt. 

Some of these factors can be avoided by leading a healthy lifestyle, but some need specific treatment to keep them under control. Therefore, getting your blood pressure or sugar checked every so often is important.

Getting checked

High blood pressure often doesn't have noticable symptoms, so a blood pressure test is key to finding out your blood pressure level. Find out more about getting your blood pressure checked. 

The main symptoms of diabetes include increased thirst, frequent trips to the toilet particularly at night, excessive tiredness, weight loss, blurred vision, slow healing of cuts and genital itching or frequent episodes of thrush. There may be no warning symptoms at all, so if you are concerned that you are at risk, ask your doctor for a diabetes check. 

Does age play a part?

Sometimes people think that it’s too late to change their habits once they get to ‘a certain age’. This is not true – it’s never too late. 

We study the little scars with special brain scans and recently found that they could disappear if high blood pressure was brought under control and possibly other lifestyle changes were adopted.

Our research has shown that not smoking and eating less salt may help to stop scars from forming. We also found that taking more exercise means you are less likely to get scars and this will reduce problems with loss of thinking and memory as you get older.

Soon, we hope to have treatments to reduce scars, but meantime, avoiding them reduces the risk of stroke and dementia, so is very important!

Healthy body, healthy mind

The main message is keep your small blood vessels healthy. Your brain is a very delicate electrical organ and needs looking after. A healthy body encourages a healthy mind and vice versa, at all ages. It is never too late to change your habits.

The brain-heart connection

Read more about how what’s good for your heart is good for your brain in a report from The Global Council on Brain Health.

About the author

Professor Joanna Wardlaw is Professor of Applied Neuroimaging in the Centre for Clinical Brain Sciences at the University of Edinburgh. She studies tiny blood vessels in the brain, how, when things go wrong, this can lead to stroke or dementia, and how to prevent this happening. She leads the brain imaging studies on the Lothian Birth Cohort 1963 as part of The Disconnected Mind project, funded by Age UK.

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Last updated: Oct 16 2023

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