DO you ever feel light-headed or dizzy when you stand up quickly?
Well, experts have warned the “head rush” sensation you experience could be a warning sign of Alzheimer’s.
Scientists who studied the effect in more than 6,000 healthy individuals found that it increased the risk of dementia by up to 39 per cent.
The sensation is caused by a temporary drop in blood pressure, which is thought to trigger brain damage if it occurs repeatedly.
The dizzy spell phenomenon – known medically as orthostatic hypotension (OH) – is particularly common among the elderly, affecting 20 to 30 per cent of this population.
For a brief period of time it can result in a shortage of blood flowing through the brain, depriving nerve cells of oxygen and nutrients.
The study tracked 6,204 men and women aged 55 and over for 15 years on average, and recorded how many of them developed any type of dementia, including Alzheimer’s.
Almost a fifth of participants regularly experienced a significant drop in blood pressure within three minutes of standing from a resting position. They were classified as being prone to OH.
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Compared with those who did not feel dizzy when standing up, this group was 15% more likely to develop dementia.
The association was especially strong when a person’s heart rate did not speed up to compensate for the momentary drop in blood pressure, the Dutch study showed.
In fact, for individuals in this category, the long-term risk of dementia was raised by 39 per cent.
The research, led by Dr Arfan Ikram, from Erasmus Medical Centre, is reported in the online journal Public Library of Science Medicine.
The authors wrote: “We found OH to be associated with long-term risk of dementia on continuous follow-up, independent of various other risk factors.
“The most apparent explanation for our findings is that OH causes brain damage due to recurrent transient cerebral hypoperfusion (low blood flow).
“Brief episodes of hypoperfusion elicited by sudden blood pressure drops may lead to hypoxia (oxygen deprivation), with detrimental effects on brain tissue via, for instance, neuro-inflammation and oxidative stress.”
We found OH (head rush) to be associated with long-term risk of dementia on continuous follow-up, independent of various other risk factorsDr Arfan Ikram, from Erasmus Medical Centre
Of the study participants who developed dementia, almost 80 per cent had Alzheimer’s disease and 8 per cent had a vascular form of the condition linked to impaired blood supply.
The relative risk of both was increased to the same extent by recurrent episodes of OH, according to the researchers.
Dr Laura Phipps, from the charity Alzheimer’s Research UK, said: “This study highlights the important role of the blood supply, not just in contributing to vascular dementia, but potentially playing a role in other forms of dementia too.
“While many studies have focused on the risks of high blood pressure, this study suggests that transient low blood pressure could also have a long term impact on the brain.
“While the risks found in this study are reasonably small compared to other known risk factors for dementia, it adds to a growing and complex picture of how blood pressure changes throughout life can impact the brain.”