A recent study indicates that middle-aged and older adults with consistent daily patterns of activity and rest may experience slower biological aging. Researchers found that participants who exhibited clear distinctions between daytime activity and nighttime rest, along with less fragmented routines, had more youthful physiological age indicators. These associations persisted even after adjusting for factors like chronological age, sex, education, and health conditions.

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Biological aging reflects how well the body functions as it ages, which can differ from a person's chronological age. Some individuals age more slowly and maintain better health, while others may age quicker due to various lifestyle factors. Epigenetic changes, which affect genes without altering the DNA, can be used to partially gauge biological aging. An epigenetic clock estimates a person's biological age, and discrepancies between epigenetic age and chronological age can indicate increased risks of age-related diseases.

The study, published in JAMA Network Open, involved 207 participants from the Baltimore Epidemiologic Catchment Area (ECA) cohort study, with an average chronological age of about 68 years. Led by the Johns Hopkins Bloomberg School of Public Health, researchers used wrist-worn actigraphy devices for approximately seven consecutive days to track activity, rest, sleep, and sedentary behavior. Participants also logged their sleep and naps.

The investigators compared these activity patterns with four established epigenetic clocks: Horvath, Hannum, PhenoAge, and GrimAge. Results showed that individuals with stronger, less fragmented rest-activity rhythms had significantly lower biological age scores on the GrimAge and PhenoAge measures. This correlation remained after accounting for age, sex, education, and certain health conditions.

Co-senior author Brion Maher, PhD, from the Bloomberg School’s Department of Mental Health, noted that the strong associations were not unexpected. He stated that the GrimAge and PhenoAge clocks were designed to capture health risks associated with aging, including mortality and physiological decline.

Though similar trends were observed with the Horvath and Hannum clocks, these findings did not reach statistical significance. The study suggests that weakened circadian rhythms, which govern sleep, activity, and various bodily functions, often accompany aging. Another study linked fragmentation in rest-activity patterns to brain shrinkage in older adults, prompting researchers to propose that rest-activity rhythms serve as useful aging markers and may provide insights into health beyond chronological age.

Lead author Chunyu Liu, a PhD student, emphasized the potential relationship between circadian regulation and aging processes. Liu commented that stronger circadian rhythmicity may help regulate biological processes tied to aging, potentially reflected in lower rates of epigenetic age acceleration.

Spira, another co-senior author, elaborated on how wrist movement measurements indirectly reflect circadian function, linking fragmented rhythms to disrupted sleep patterns. The study, being cross-sectional, does not clarify whether disrupted rhythms cause faster aging or stem from aging itself. Longer-term studies are required to better understand this relationship.

The researchers emphasized the value of wearable technology in monitoring physiological aging and health risks in real time, suggesting that such devices could identify individuals with disrupted daily rhythms, aiding earlier interventions. They conclude that maintaining regular daily routines, consistent sleep and wake schedules, and engaging in physical activity may reinforce healthier rhythms.

Their practical advice includes regular meal and bedtime schedules, avoiding daytime naps, and managing light exposure to align biological clocks with the environment. Future clinical trials may explore whether enhancing daily rest-activity rhythms can help mitigate biological aging.