The biological age of humans and mice undergoes a rapid increase in response to diverse forms of stress, which is reversed following recovery from stress, according to a study publishing on April 21 in the journal Cell Metabolism. These changes occur over relatively short time periods of days or months, according to multiple independent epigenetic aging clocks.
“This finding of fluid, fluctuating, malleable age challenges the longstanding conception of a unidirectional upward trajectory of biological age over the life course,” says co-senior study author James White of Duke University School of Medicine. “Previous reports have hinted at the possibility of short-term fluctuations in biological age, but the question of whether such changes are reversible has, until now, remained unexplored. Critically, the triggers of such changes were also unknown.”
The biological age of organisms is thought to steadily increase over the life course, but it is now clear that biological age is not indelibly linked to chronological age. Individuals can be biologically older or younger than their chronological age implies. Moreover, increasing evidence in animal models and humans indicates that biological age can be influenced by disease, drug treatment, lifestyle changes, and environmental exposures, among other factors.