New research has shown that fluctuating blood pressure can increase the risk of dementia and heart problems in older people.
Researchers from the University of South Australia (UniSA) have found short blood pressure fluctuations within 24 hours and over several days or weeks were linked with impaired cognition.
The study also found that higher systolic blood pressure variations – the number that measures the pressure in arteries when a heart beats – are also linked with stiffening of the arteries, usually associated with heart disease.
Lead author of the research Daria Gutteridge said it was common knowledge that high blood pressure was a risk factor for dementia, but little attention was paid to fluctuating blood pressure.
"Clinical treatments focus on hypertension while ignoring the variability of blood pressure," Ms Gutteridge said.
"Blood pressure can fluctuate across different time frames – short and long – and this appears to heighten the risk of dementia and blood vessel health."
More than 400,000 Australians live with dementia.
That number is estimated to jump to 900,000 in the next 25 years, with the recent Intergenerational Report estimating Australia's older population to triple.
Seventy per cent of aged-care residents live with moderate to severe cognitive impairments, including dementia.
The Australian Institute of Health and Welfare found high blood pressure to increase with age – from 10 per cent or less among 18-34-year olds to 47 per cent for 85 and over.
The study recruited 70 healthy adults aged 60 to 80, with no signs of dementia or cognitive impairment.
Their blood pressure was monitored, and arterial stiffness in the brain and arteries was measured.
"We found that higher blood pressure variability within a day, as well as across days, was linked with reduced cognitive performance," Ms Gutteridge said.
"We also found that higher blood pressure variations within the systolic blood pressure were linked with higher blood vessel stiffness in the arteries."
"These results indicate that the different types of blood pressure variability likely reflect different underlying biological mechanisms, and that systolic and diastolic blood pressure variation are both important for cognitive functioning in older adults."
The links were present in older adults without clinically relevant cognitive impairment, meaning that blood pressure variability could serve as an early clinical marker or treatment target for cognitive impairment.
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