New heart rate measure offers clues to future cognitive health

Healthy hearts are adaptable, and heartbeats exhibit complex variation as they adjust to tiny changes in the body and environment. Mass General Brigham researchers have applied a new way to measure the complexity of pulse rates, using data collected through wearable pulse oximetry devices. The new method, published in Journal of the American Heart Association, provides a more detailed peek into heart health than traditional measures, uncovering a link between reduced complexity and future cognitive decline.

"Heart rate complexity is a hallmark of healthy physiology," said senior author Peng Li, PhD, of the Department of Anesthesia, Critical Care and Pain Medicine at Massachusetts General Hospital (MGH) and the Division of Sleep and Circadian Disorders at Brigham and Women's Hospital (BWH), both founding members of the Mass General Brigham healthcare system. "Our hearts must balance between spontaneity and adaptability, incorporating internal needs and external stressors."

The study used data from 503 participants (average age 82, 76% women) in the Rush Memory and Aging Project. The researchers analyzed overnight pulse rate measurements-collected by a fingertip pulse oximetry device known as the Itamar WatchPAT 300 device-and comprehensive measures of cognitive functions, collected around the same time as the pulse rate measurement and at least one annual follow-up visit up to 4.5 years later.

The team found that people with greater complexity in their heartbeats at baseline tend to experience slower cognitive decline over time. They determined that the conventional measures of heart rate variability did not predict this effect, indicating their measure was more sensitive in capturing heart functions predictive of cognitive decline.

The researchers plan to investigate whether pulse rate complexity can predict development of dementia, which would make it useful for identifying people at an early stage who might benefit from therapeutic interventions.

The findings underscore the usefulness of our approach as a noninvasive measure for how flexible the heart is in responding to nervous system cues. It is suitable for future studies aimed at understanding the interplay between heart health and cognitive aging."

Chenlu Gao, PhD, lead author, Department of Anesthesia, Critical Care and Pain Medicine at MGH