High blood pressure accelerates brain aging


People with elevated blood pressure that falls within the normal recommended range are at risk of accelerated brain aging, according to new research from The Australian National University (ANU).

The research also found optimal blood pressure helps our brains stay at least six months younger than our actual age. The researchers are now calling for national health guidelines to be updated to reflect their important findings.

The ANU study, published in Frontiers in Aging Neuroscience, found participants with high blood pressure had older and therefore less healthy brains, increasing their risk of heart disease, stroke and dementia.

Participants with an elevated blood pressure, but within the normal range, also had older looking brains and were at risk of health problems.

“This thinking that one’s brain becomes unhealthy because of high blood pressure later in life is not completely true,” Professor Nicolas Cherbuin, Head of the ANU Centre for Research on Aging, Health and Wellbeing, said.

“It starts earlier and it starts in people who have normal blood pressure.”

Normal blood pressure is defined by pressure below 120/80, whereas an optimal and healthier blood pressure is closer to 110/70.

The new research comes after a large international study found the number of people over 30 with high blood pressure has doubled globally.

Cardiologist and co-author of the study, Professor Walter Abhayaratna, said if we maintain optimal blood pressure our brains will remain younger and healthier as we age.

“It’s important we introduce lifestyle and diet changes early on in life to prevent our blood pressure from rising too much, rather than waiting for it to become a problem,” he said.

“Compared to a person with a high blood pressure of 135/85, someone with an optimal reading of 110/70 was found to have a brain age that appears more than six months younger by the time they reach middle age.”

The ANU team, in collaboration with colleagues in Australia, New Zealand and Germany, examined more than 2,000 brain scans of 686 healthy individuals aged 44 to 76.

The blood pressure of the participants was measured up to four times across a 12-year period. The brain scan and blood pressure data was used to determine a person’s brain age, which is a measure of brain health.

Lead author, Professor Cherbuin, said the findings highlight a particular concern for young people aged in their 20s and 30s because it takes time for the effects of increased blood pressure to impact the brain.

“By detecting the impact of increased blood pressure on the brain health of people in their 40s and older, we have to assume the effects of elevated blood pressure must build up over many years and could start in their 20s. This means that a young person’s brain is already vulnerable,” he said.

Professor Abhayaratna said the research findings show the need for everyone, including young people, to check their blood pressure regularly.

“Australian adults should take the opportunity to check their blood pressure at least once a year when they see their GP, with an aim to ensure that their target blood pressure is closer to 110/70, particularly in younger and middle age groups,” he said.

“If your blood pressure levels are elevated, you should take the opportunity to speak with your GP about ways to reduce your blood pressure, including the modification of lifestyle factors such as diet and physical activity.”

Hypertension affects two-thirds of people aged >60 years and significantly increases the risk of both vascular cognitive impairment and Alzheimer’s disease. Hypertension compromises the structural and functional integrity of the cerebral microcirculation, promoting microvascular rarefaction, cerebromicrovascular endothelial dysfunction and neurovascular uncoupling, which impair cerebral blood supply. In addition, hypertension disrupts the blood–brain barrier, promoting neuroinflammation and exacerbation of amyloid pathologies.

Ageing is characterized by multifaceted homeostatic dysfunction and impaired cellular stress resilience, which exacerbate the deleterious cerebromicrovascular effects of hypertension. Neuroradiological markers of hypertension-induced cerebral small vessel disease include white matter hyperintensities, lacunar infarcts and microhaemorrhages, all of which are associated with cognitive decline.

Use of pharmaceutical and lifestyle interventions that reduce blood pressure, in combination with treatments that promote microvascular health, have the potential to prevent or delay the pathogenesis of vascular cognitive impairment and Alzheimer’s disease in patients with hypertension.

Key points

  • Hypertension is associated with ageing and significantly increases the risk of vascular cognitive impairment and Alzheimer’s disease.
  • In older individuals, hypertension leads to maladaptation of the cerebral circulation, resulting in dysregulation of cerebral blood flow, microvascular rarefaction, blood–brain barrier disruption, oxidative stress and impaired neurovascular coupling.
  • Hypertension causes pathological alterations in cerebral microvessels that damage microvascular structure, network architecture and function, and contribute to the genesis of cerebral microhaemorrhages, lacunar infarcts and white matter injury; these factors are associated with cognitive decline.
  • Potential mechanisms by which hypertension could exacerbate the progression of Alzheimer’s disease include increased oxidative microvascular damage, brain inflammation and blood–brain barrier disruption, as well as impaired glymphatic (also known as glial-lymphatic) clearance of amyloid-β.
  • Use of pharmaceutical and/or lifestyle interventions that reduce blood pressure in combination with treatments that promote microvascular health could potentially prevent or delay cognitive decline in patients with hypertension.

reference link :https://www.nature.com/articles/s41581-021-00430-6

More information: Nicolas Cherbuin et al, Optimal Blood Pressure Keeps Our Brains Younger, Frontiers in Aging Neuroscience (2021). DOI: 10.3389/fnagi.2021.694982


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