Blood pressure and brain health: what’s the link?
If you’ve completed the Think Brain Health Check-in recently, you may have noticed that one of the questions asks about your blood pressure.
Why ask this question? Blood pressure is important for brain health because of its link to good heart health – and being heart healthy is one of Alzheimer’s Research UK’s three simple rules for better brain health.
Let’s dig into the research to explore what we know about the way our blood pressure affects the brain’s ability to function.
What exactly is blood pressure?
We need pressure to get our blood moving around our body – it’s crucial to our survival. As blood is pumped around the body, it delivers a vital supply of oxygen and nutrients to our organs, including the brain.
When your blood pressure is taken, two different things are measured:
- ‘Systolic’ pressure, which is the pressure when your heart pumps blood around the body.
- ‘Diastolic’ pressure, which is the pressure when your heart rests in between beats.
This is why you’ll hear doctors describe a blood pressure reading with two numbers. For example, a reading of 120/80 mmHg (‘120 over 80’) would be considered to be within the healthy range for most people.
How high blood pressure impacts the brain
Our blood pressure naturally goes up and down over the course of the day, depending on what we are doing. But if our blood pressure is too high for too much of the time – known as ‘hypertension’ – this can cause problems. For someone in midlife, a blood pressure reading of 140/90 mmHg or more would be considered high.
Left untreated, high blood pressure can cause damage to blood vessels, leading to reduced blood flow and a greater risk of arteries becoming clogged. This in turn increases the risk of serious health problems such as a heart attack or stroke. When it comes to brain health, reduced blood flow to the brain can affect our ability to think and remember, and can also increase the risk of developing dementia.
The good news is, we can help to reduce high blood pressure by following the first of our three simple rules for brain health – love your heart. This includes eating a healthy, balanced diet, keeping physically active, not smoking and drinking less than 14 units of alcohol a week. Depending on the cause, some people may also benefit from medication to help bring their raised blood pressure down to a healthy level.
The importance of treating high blood pressure: the SPRINT MIND study
In 2010, researchers set up an important study called SPRINT MIND to see how the way we treat high blood pressure can affect people’s brain health.
More than 9,000 volunteers took part, all of whom were over 50 and had been diagnosed with high blood pressure. The researchers split them into two groups:
- Those in group 1 were given standard treatment, to reduce their systolic blood pressure to less than 140 mmHg.
- People in group 2 received more intensive treatment, to reduce their systolic blood pressure to less than 120 mmHg.
The volunteers took a series of memory and thinking tests after two and four years.
In the end, the study was stopped early when it became clear that people in group 2 had much better heart health. The intensive treatment was saving lives, and it wouldn’t have been ethical to withhold it from people in group 1.
But the researchers also found that those on the intensive treatment were less likely to have developed thinking and memory problems known as mild cognitive impairment, which is considered a high-risk state for developing dementia. The results suggest that reducing high blood pressure down to healthy levels is important for protecting brain health.
What should I be doing?
You may be reading this and wondering what all this means for your own brain health.
Most importantly, if you have been diagnosed with high blood pressure, the best advice is to discuss this with your doctor and to take any treatment seriously. This might include some changes to your diet, how much you drink, and how physically active you are. For some people, your doctor may prescribe drugs to help control your blood pressure.
Blood pressure tends to increase as we get older. That’s why, if you’re under the age of 40, you’re generally considered to have a lower risk of having high blood pressure (although the NHS recommends getting it checked if you’re worried about it at any age). If you’re over 40 and haven’t had your blood pressure checked in the last five years, getting a test is the first step to understanding whether you might need to make any changes.
About the author
Prof Rob Howard
Professor of Old Age Psychiatry at University College London
Prof Rob Howard is Professor of Old Age Psychiatry at University College London and Honorary Consultant Psychiatrist at Camden and Islington NHS Trust. He has over 30 years' experience working in the clinic with people with dementia, and as a researcher working to find and evaluate better treatments. Prof Howard is also a Scientific Trustee of Alzheimer’s Research UK.