A study coordinated by Harvard and Duke Universities has shown that stressful situations such as emergency surgery or severe COVID-19 can accelerate biological age, but this fluctuation is reversible. The researchers used various epigenetic clocks to measure aging, finding that these changes can occur over relatively short time periods of days or months.
Biological age is not necessarily indelibly related to chronological age, and individuals may be biologically older or younger than their chronological age implies. The former can be influenced by disease, drug treatments, lifestyle changes, or environmental exposures.
The team used epigenetic clocks of DNA methylation to measure the biological age of humans and mice in response to various stressful stimuli. The results showed that biological age can increase for relatively short periods of time in response to stress, but this increase is transient and tends to return to baseline after recovery from stress.
The study also suggests that other natural situations can trigger reversible changes in biological age, such as emergency surgery, pregnancy, and severe COVID-19. In these cases, patients experienced a sharp and rapid increase in biological age, but after the stressful situation, biological age returned to baseline values.
Although the study highlights an underappreciated aspect of the nature of biological aging, the researchers acknowledged some limitations in their ability to probe the connections between short-term fluctuations in biological age and lifetime trajectories of biological aging. In summary, the finding of a fluid, fluctuating, and malleable age challenges the long-standing conception of a unidirectional upward trajectory of biological age across the lifespan.