People age differently but it is unclear why. Some argue it is mitochondria while others contend it is equally nebulous epigenetics - a broad umbrella term for changes in genes that don't impact DNA but have been correlated to everything from probiotic yogurt to homeopathy.

Because so-called “epigenetic clocks” occur at different times in different people they don't seem like clocks at all. There is little use for a clock that only gives you subjective time. A new study hopes to change that, and argues that one such clock, named “GrimAge”, might be a predictor of lifespan and health.

A new study asked two questions: How much does chronic stress accelerate that biological clock? And are there ways to slow it down and extend a healthy lifespan? The authors say stress does imake life’s clock tick faster but that individuals can help manage the effects by strengthening their emotion regulation and self-control.

Stress has been correlated by epidemiologists to heart disease, addiction, mood disorders, post-traumatic stress disorder, metabolism, and somehow even diabetes. The new study sought to clear up some of the confusion by enrolling 444 people, ages 19 to 50, who provided blood samples used to evaluate the age-related chemical changes captured by GrimAge as well as other markers of health. The participants also answered questions designed to reveal stress levels and psychological resilience, which is an obvious confounder. 

After controlling for smoking, body mass index, race, and income, the researchers found that those who scored high on measures related to chronic stress exhibited accelerated aging markers and physiological changes such as increased insulin resistance.

However, stress didn’t affect everyone’s health to the same degree. Subjects who scored high on two psychological resilience measures — emotion regulation and self-control — were more resilient to the effects of stress on aging and insulin resistance, respectively. The more psychologically resilient the subject, the higher the likelihood they would live a longer and healthier life