Many people know that high blood pressure is a major cause of heart attacks, but many do not know that it can damage the blood vessels in many organs, including the brain.
High blood pressure in your middle age is linked with a small but important increase in risk of dementia, particularly with a form of dementia called Vascular Dementia, and then to a lesser extent, Alzheimer’s disease.
Conversely, very low blood pressure at more advanced age is also associated with increased risk of dementia.
Not only is high blood pressure common, it also tends to go up as we pass through middle age.
As there are not normally any symptoms until your blood pressure gets very high, it is possible to have high blood pressure but do not know it.
For this reason, if you have not had your blood pressure checked for a while, you have a reasonable risk of having high blood pressure.
As we get older, in our late 70s or 80s, low blood pressure may also develop, which can make people weak, dizzy or confused, more likely to fall and even possibly pass out.
So, at this age we start to think less about causing more long-term damage from higher blood pressure and are more careful about not over treating blood pressure with medication.
Why is high blood pressure dangerous?
As you heart pumps, blood presses on your artery walls.
The blood pressure readings that you hear of refer to how much pressure is on your arteries; the top number is the higher pressure when your heart beats, and the lower number is from when you heart is relaxed between
An optimal blood pressure reading is a little under 120/80mmHg.
Blood pressure over 140/90 mmHg is usually regarded as being high.
If this pressure is too high for too long, it can speed up the accumulation of plaque on artery walls.
If this plaque blocks blood flow to your heart’s muscle, it puts you at risk of a heart attack.
Being overweight, not getting enough exercise, smoking and stress can all contribute to high blood pressure, and are also additional, likely related, risks for many forms of dementia.
Research clearly shows that people who have cardiovascular diseases such as a stroke are at very high risk of dementia in the future.
High blood pressure is also likely linked to damage to the very fine blood vessels in the deep parts of the brain.
A combination of multiple small strokes and this damage to small blood vessels in the brain is a typical cause of vascular dementia.
Small vessel disease is also linked to greater susceptibility to Alzheimer’s disease.
At what age do we want to control blood pressure to reduce the risk of dementia?
Blood pressure tends to increase first as people reach middle age - between 40 and 60 years of age.
Getting blood pressure under control at this point in time is likely to reduce the risk of brain injury later on, remembering that high blood pressure does its damage over time - so clearly careful monitoring and control of blood pressure during middle age is important to both cardiovascular and brain health.
While the current population-based evidence indicates an important link between high blood pressure in midlife and dementia risk, we are not yet certain that treating high blood pressure with medication reduces this risk.
A number of large studies around the world are looking into this.
Non-drug approaches to vascular health, such as losing weight, a healthier diet and increasing exercise are all likely to improve brain health in general and reduce the risk of dementia later in life.
Contributed by: The ISLAND Project
Wicking Dementia Research and Education centre
High blood pressure is one of the most common health conditions, affecting around a third of Australians over the age of 50.