Don’t blow a gasket. Keep your blood pressure down to save your brain.


I was sitting in my GP’s office recently, being told something I didn’t want to hear. My blood pressure was too high and I needed to start medication with antihypertensives.

I didn’t want to have to take medication. I had always planned not to be on anything apart from fish oil and glucosamine supplements until I was at least 90 years old. I consider myself fit. I exercise daily, my weight is normal, I eat healthily, I don’t smoke and I keep an eye on how much wine I drink each week.

But my family history includes hypertension and stroke on both my mother’s and father’s side.
And I do recall a conversation with my obstetrician who was managing my pregnancy-induced hypertension a number of years ago. He said, “Jenny, you are likely to develop hypertension as you get older.” Harrumph. I heard, but didn’t want to listen. But who am I trying to kid?

I have what is called “essential hypertension”. The cause is as yet unknown.
I don’t like it. But I can deal with it and take my pills.
The reason why? Because I value my brain cells too highly not to. As a Doctor my medical training has taught me what the consequences of untreated hypertension are.

Hypertension has been described as a silent killer. You can’t feel if your blood pressure is too high. We rely on readings taken with a sphygmanometer to get an accurate idea of the state of our blood vessels.
The blood pressure reading essentially tells us the peak or systolic pressure our heart has to exert with each contraction to pump the blood around our body. The lower reading or diastolic pressure gives us the resting pressure of the circulatory system in between heartbeats.

If the readings are too high we run the increased risk over a period of time of blood vessel rupture causing a stroke or cerebrovascular accident. Other organs are affected as well, including the kidney, eye and heart. None of which is good news.

So, back to the brain and high blood pressure. Sure it’s good not to be at risk of stroke. But what about the effect of high blood pressure on memory and cognition?

Studies have shown that having high blood pressure can contribute to memory loss and other decline in brain function in people over the age of 45.

In one study of over 19000 participants aged 45 or older, they found that with each 10-point increase in diastolic pressure, the risk of cognitive difficulty increases by 7 points.

But how high is high?
We need to keep our diastolic pressure (the lower of the two reading indicating the pressure of the arterial system at rest) at below 90mmHg.

With around 25-30% of the Australia adult population having high blood pressure I am clearly not alone.
For the vast majority of people like myself we have “essential hypertension” where no specific cause is identified. However having high blood pressure causes problems by causing our arterial walls to thicken and lose their elasticity, leading to reduced blood flow and tissue death.

Having reduced blood flow to your brain becomes an issue when you need it to be working harder. For example when you want to be able to pay attention or work out a solution to a problem, the decrease of available blood flow to your brain leads to fewer brain cells being activated and an increased number of memory lapses happening as a result.

In older people, having high blood pressure can predict who is at risk of developing impaired executive function (organising, planning and decision making) and a greater risk of progressing to dementia. One study of 900 octogenarians showed that high blood pressure was associated with an increased risk of developing dementia when frontal lobe functioning was impaired

Because stroke and TIA are leading causes of risk of cerebrovascular disability followed by dementia, controlling hypertension is a simple and effective way to significantly potentially reduce the incidence of forecasted dementia in this group.

So attending to diagnosing and treating hypertension in midlife would appear to be essential to protect you from developing cognitive impairment further down the track.

If you are over 45 and haven’t had your blood pressure checked for a while, now would be a good time to make an appointment and get it checked by your GP.

If it is too high then some simple lifestyle changes could help:

• Keeping your weight in the healthy range
• Don’t smoke
• Reduce your alcohol consumption.
• Do some regular exercise
• Keeping your cholesterol in the normal range
• Eat less saturated fat.
• Use less salt in your diet.

Hypertension has no symptoms, but is easily managed and keeping it in the normal range could make a big difference to being able to save your brain.

References:
Shahram Oveisgharan; Vladimir Hachinski. Hypertension, Executive Dysfunction, and Progression to Dementia: The Canadian Study of Health and Aging. Arch Neurol, 2010; 67 (2): 187-192

JAMA and Archives Journals (2007, December 12). High Blood Pressure Associated With Risk For Mild Cognitive Impairment.

Radiological Society of North America (2007, November 29). High Blood Pressure May Heighten Effects Of Alzheimer’s Disease.

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