Washington - (Saba):
A new study has shown that subtle variations in a person's heart rate may provide clues about the likelihood of future cognitive decline, potentially providing a valuable new test for cognitive problems that would be quick and easy.
This is something researchers have been devoting a lot of time to, because knowing when cognitive decline begins and how it progresses means better support and greater clarity for those affected. This research also reveals new insights into how these conditions develop and how they can be halted, according to Science Alert.
In this study, published in the Journal of the American Heart Association, an international team analyzed heart rate data across a night's sleep for 503 people with an average age of 82. Cognitive tests were also performed around the same time, as well as at at least one follow-up visit.
Using a statistical model called distribution entropy, which predicts health outcomes, the researchers found an association between heart rate complexity—the extent to which heart rate changes and adapts throughout the night—and cognitive decline in later years.
"Higher heart rate complexity is associated with slower cognitive decline in older adults," the researchers wrote in their published paper. In contrast, lower complexity was found to be associated with accelerated cognitive decline...Future studies should test whether complexity is also associated with future risks of neurodegenerative disorders, such as dementia, and further clarify causal trends.
Distribution entropy is a relatively new alternative method for measuring heart rate and its corresponding pulse rate in the body. Researchers have already linked this complexity in resting heartbeats to other health risks, including heart and respiratory problems.
The idea is that a more adaptable heart is a healthier heart. If the heart undergoes a more complex set of changes in response to what's happening in the body, it runs more nimbly and quickly, like a runner changing speed and direction.
Links between heart rate variability and cognitive function have been suggested previously, but this new type of measurement appears to go further, even predicting brain health problems before noticeable symptoms appear.
"Heart rate complexity is the hallmark of healthy physiology," says biomedical engineer and computational physiology expert Bing Li of Massachusetts General Hospital...and it should be considered. Our hearts balance spontaneity and adaptability, integrating internal needs and external stressors.
The researchers found that more traditional measures of heart rate showed no association with subsequent cognitive decline in this study, suggesting that the entropy distribution approach may be more sensitive to changes in the body's health.
Further research can now examine why this association exists and the biological pathways through which it operates. The team also wants to examine whether there is a relationship between the onset of dementia and cognitive decline.
"The results underscore the utility of our approach as a non-invasive measure of how flexible the heart is in responding to nervous system signals," says Chenlu Zhao, lead author and sleep scientist at Brigham and Women's Hospital. "They are relevant for future studies aimed at understanding the interplay between heart health and cognitive aging."