Adults with stronger and more consistent daily patterns of rest and activity showed signs of slower aging, new research revealed. The findings suggest that stronger, more stable, and less fragmented rhythms may slow down physiological aging.

Rest-activity rhythms typically weaken in later life, but the chronological age of an older adult may not reflect actual biological decline, according to the authors. Long-term exposure to factors such as high blood sugar, systemic inflammation, and cigarette smoke accelerates the aging process throughout the body. In recent years, scientists have developed blood tests to measure the degree of this “physiological aging” by analyzing changes in epigenetic marks—small chemical modifications on DNA that can change over time.

For the study, researchers analyzed data on 207 adults (average age, 68) in the Baltimore Epidemiologic Catchment Area cohort study, comparing rest-activity rhythm data from wrist-worn devices with blood tests that measure biological aging. The researchers tracked participants’ rest-activity rhythms over approximately seven consecutive 24-hour periods. Rest could include sedentary activities such as sitting and reading a book or eating a meal, as well as daytime napping and nighttime sleep; participants also kept nap/sleep logs.

Researchers then compared each participant’s rest-activity rhythms with their scores on four standard “epigenetic clocks”—physiological age estimates derived from blood samples—known as Horvath, Hannum, PhenoAge, and GrimAge. 

Stronger rhythms, which were characterized by bigger differences between daytime and nighttime activity levels, as well as less fragmented rest-activity rhythms and greater day-to-day rhythm consistency were significantly associated with more youthful physiological age scores. These associations held after accounting for chronological age and other relevant factors, including sex, education level, and certain health conditions.

The researchers expect that research in this field will someday enable older adults and/or their doctors to monitor markers of physiological aging or other health risks via their wearable devices.

To download the study, published in JAMA Network Open, click here