An elevated heart rate in old age could be a risk factor of dementia, according to a study at Karolinska Institutet in Sweden published in the journal Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association.
Dementia is a syndrome (a group of related symptoms) associated with an ongoing decline of brain functioning. Symptoms include problems like memory loss, movement and thinking speed, with experts now believing that an elevated heart rate could be used to identify individuals at risk of dementia and allow early intervention by medical professionals.
It is believed that individuals living with dementia will rise to 139 million globally by 2050, from 55 million in 2020, according to research by the organisation Alzheimer’s Disease International.
Elevated heart rate and risk of dementia
The researchers examined whether resting heart rate in 2,147 individuals 60 years of age or older and living in Stockholm could be linked to dementia and cognitive decline independent of other known risk factors, such as cardiovascular disease.
The study followed the participants for up to 12 years and highlighted how resting individuals with an elevated heart rate of 80 beats per minute or higher on average had a 55% higher risk of dementia than those with a heart rate of 60-69 beats per minute. The association remained significant after adjusting for potential variables such as cardiovascular diseases. Regardless, the research team cautioned that their results could have been influenced by undetected cardiovascular events and the fact that more participants with a cardiovascular disease died during the follow-up period, so they didn’t have time to develop dementia.
Resting heart rate can be lowered through exercise or medical treatment, and uncovering patients with an elevated heart rate could mean an earlier intervention.
Underlying cardiovascular diseases and risk factors
The study cannot establish a causal relationship, but the researchers offer several plausible explanations for the association of an elevated heart rate and dementia, including the effect of underlying cardiovascular diseases and cardiovascular risk factors, stiffened arteries, and imbalance between sympathetic and parasympathetic nerve activities.
“We believe it would be valuable to explore if resting heart rate could identify patients with high dementia risk,” said the study’s leading author Yume Imahori, a researcher at the Department of Neurobiology, Care Sciences and Society, Karolinska Institutet. “If we follow such patients’ cognitive function carefully and intervene early, the onset of dementia might be delayed, which can have a substantial impact on their quality of life.”
The research was funded by the Swedish Ministry of Health and Social Affairs, the Swedish Research Council, the Swedish Research Council for Health, Working Life and Welfare, the Swedish Foundation for International Cooperation in Research and Higher Education, Karolinska Institutet and the European Union.