Checking older adults' resting heart rate could help identify those who are more likely to experience a decline in mental function, a Swedish study suggests.

The researchers found that a high resting heart rate was associated with a greater risk of dementia.

"We believe it would be valuable to explore if resting heart rate could identify patients with high dementia risk," said lead author Dr. Yume Imahori, of the Aging Research Center at the Karolinska Institute in Stockholm.

"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," Imahori added in an institute news release.

For the study, her team followed more than 2,100 people in Stockholm for up to 12 years. Participants were aged 60 and up.

On average, those with a resting heart rate of 80 beats or more per minute had an average 55% higher risk of dementia than those with a heart rate of 60 to 69 beats per minute.

The link between a higher heart rate and dementia remained significant even after the researchers accounted for factors such as heart disease, according to findings published online Dec. 3 in Alzheimer's & Dementia: The Journal of the Alzheimer's Association.

Even so, the authors noted that their findings may have been affected by undetected heart disease and the fact that more participants with heart disease didn't live long enough to develop dementia.

The researchers also stressed that their study didn't prove a cause-and-effect relationship between high resting heart rate and dementia risk.

Resting heart rate can be lowered through exercise or medical treatment, the team explained.

The study authors said there are several possible explanations for the association between high resting heart rate and increased dementia risk. They include the effects of underlying heart disease and risk factors, stiffened arteries, and imbalance between nervous systems that prepare the body for restful situations or activate the fight-or-flight response.

Worldwide, the number of people with dementia is expected to reach 139 million by 2050, according to Alzheimer's Disease International. There is no cure for dementia, but growing evidence suggests that a healthy lifestyle and good heart health could help delay its onset and ease symptoms.