A rush of blood to the head

05 July 2009
Posted by Chris Smith.

We often talk about angry people as having had a metaphorical sudden rush of blood to the head, but new research from scientists in the US, published in the journal Cardiovascular Ultrasound suggests that it might actually be true.

Protests surround Mahmoud Ahmadinejad at Columbia by David Shankbone.This is research by Tasneem Naqvi and Hahn Hyuhn, who were using ultrasound to look at blood flow in the brain in response to mental stress, and also how the main artery to the brain, the carotid, responds under these circumstances. They studied 10 healthy young people, aged 19 to 27, 20 older people, aged 38 to 60, and 28 people with high blood pressure.

The researchers set the volunteers a series of tasks designed to cause mental stress, including reading, maths tests, and remembering situations when they were angry, while using ultrasound to monitor the effects on blood flow in the brain, blood pressure, and heart rate.

The scientists discovered that in healthy volunteers, the blood flow to the brain increased under mental stress, through a process called vasodilation - where the blood vessels get wider to allow more blood through.  But in patients with high blood pressure, known as hypertension, they didn't see this vasodilation, and found no significant changes in blood flow in the brain.

Obviously, this is only a very small study, but it does have some interesting implications. The researchers suggest that the lack of vasodilation in people with high blood pressure could be a risk factor for strokes. It's known that a lack of vasodilation in the heart can lead to an increased risk of something called myocardial ischaemia - a lack of oxygen to the heart muscle.

It will be interesting to see if the lack of vasodilation in people with high blood pressure could increase the risk of stroke - which is a lack of blood and oxygen in certain parts of the brain.  And the results also raise the question as to whether a lack of blood flow to the brain could affect mental performance in people with high blood pressure. So the work raises lots of future avenues for research.

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