Circadian rest-activity patterns may signal frailty risk in older adults

Brigham researchers found an association between changes in circadian rest-activity rhythms and frailty risk in older adults.

Wearable devices can be used to measure various signs and signals related to our health. A new study by researchers at Brigham and Women’s Hospital, a founding member of the Mass General Brigham Health Care System, suggests that such devices may be able to predict frailty-related health complications in older adults. The team found an association between disruptions in daily patterns of rest and activity, or circadian rest-activity rhythms, and a higher risk of developing frailty over time and progression. The rhythms were recorded from wearable devices and, in some cases, could detect variations that suggested future frailty more than six years before the event. Results are published Nature communication.

Our study shows that wearable devices may represent an important tool for long-term health monitoring of older adults. “Love can reduce quality of life, and identifying it early or predicting who is at risk can help us intervene to promote healthy aging.”

Ruixu Cai, lead author, is a doctoral candidate in the Department of Sleep and Circadian Disorders

Frailty, or age-related decline in physiological function, is a common condition in the elderly population that increases their vulnerability to adverse health outcomes. Disrupted circadian rest-activity rhythms have previously been linked to neurodegenerative diseases such as Alzheimer’s disease and Parkinson’s disease. Research has also shown that aging alters these rest-activity patterns, with older people often preferring to keep earlier hours than younger adults.

The authors studied a cohort of 1,022 adults with an average age of 81, recruited as part of the Rush Memory and Aging Project, who were followed annually for up to 16 years. The researchers analyzed continuous rest and activity data from the wearable device, including measures such as amplitude, stability and rhythm variability.

Over an average of six and a half years, the team observed that 357 participants developed frailty. Blunt, less vigorous, or inconsistent rest-activity patterns were associated with higher risk of events. These disturbances were also associated with rapid worsening of frailty progression symptoms such as decreased grip strength, decreased body mass index, and increased fatigue. Results were independent of characteristics such as age, sex, sleep duration, sleep fragmentation, and cardiovascular dysfunction.

The authors noted that circadian disruptions have previously been associated with sleep disorders, altered metabolism and neuronal damage, suggesting an overlap between the mechanisms behind vulnerability and cognitive impairment.

The study was limited to an elderly population over 80 years of age. Rest-activity patterns can be affected by seasonal changes and environmental conditions, and wearable devices can sometimes misinterpret sleep-wake cycles. Future studies with better sleep assessments are needed to better understand the causal link between circadian disruption and frailty.

“Wearable technology provides a holistic approach to identifying common indicators of disease,” said corresponding author Peng Li, PhD, Brigham Division of Sleep and Circadian Disorders and Anesthesia, Department of Critical Care and Pain Medicine, Massachusetts General Hospital. “Integrating circadian rest-activity data with other clinical measures may aid early identification and intervention in susceptible populations.”