High blood pressure at night increases risk of memory decline 

15 April 2020

Research from the US has found that people with high blood pressure that gets even higher at night are at increased risk of vascular disease and memory loss. The research was published in the scientific journal, Neurology, today (Wednesday 15 April). 

What is dipping?

A person’s blood pressure usually goes down at night. This phenomenon is known as dipping. 

But for some people, particularly those with high blood pressure, nighttime blood pressure can stay the same or even increase. 

Who did the scientists study?

The researchers studied 435 people living in Maracaibo, North West Venezuela. The study volunteers recorded their own blood pressure for 24 hours a day. They did this by wearing a device that took their pressure every 15 minutes during the day and every 30 minutes at night.  

The participants also had brains scans and undertook memory tests. 

The researchers then looked at the effect of high blood pressure and night-time dipping status on a key marker of blood supply related damage to the brain, and people’s memory skills.

What did they find?

Nearly 60% of the study volunteers had high blood pressure. 10% of volunteers were reverse dippers – their blood pressure went up at night – and 40% were nondippers – their blood pressure stayed the same 

They found that having high blood pressure and increased blood pressure at night is linked to increased signs of vascular disease in the brain and worsened memory. 

 The size of small lesions in brain tissue, known as white matter hyperintensities, was linked to the effect of dipping status and hypertension on memory scores. 

What our expert said: 

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Dr Sara Imarisio, Head of Research at Alzheimer’s Research UK, said:

“High blood pressure, particularly in midlife, is a strong risk factor for dementia. While age and genetics play an important role, research also shows that up to a third of our risk for dementia may be modifiable. In other words, dementia isn’t an inevitable part of getting older.

 “This study suggests that it’s not just daytime blood pressure that affects dementia risk but blood pressure levels throughout the day and night. Although the phenomenon of reverse dipping during the night is an accepted measure of cardiovascular risk, the affect that reverse dipping has on dementia risk is a relatively understudied area of research.

In times like this, it’s especially important we retain a healthy lifestyle for all aspects of our health. What’s good for the heart is also good for the brain. As well as maintaining a healthy blood pressure, the best evidence suggests that not smoking, only drinking in moderation, staying mentally and physically active, eating a balanced diet, and keeping cholesterol levels in check can all help to keep our brains healthy as we age.”

Neurology: White matter hyperintensities mediate the association of nocturnal blood pressure with cognition