“Chronic stress accelerates biological aging”

The claim traces back to a single study published in 2004, and it is still the one people quote. Among healthy premenopausal women, those reporting the most stress had telomeres shorter by the equivalent of at least an extra decade of ageing than the least-stressed women [1]. Telomeres are the protective caps on the ends of your chromosomes, and they wear down as you get older. Those same women also had less telomerase, the enzyme that rebuilds the caps [1].

The follow-up work over the two decades since has been more sober than that headline.

The broadest look so far pooled nine separate groups of people, 2,186 adults in total, and measured ageing with epigenetic clocks, which are lab tests that estimate biological age from chemical marks on DNA. Childhood trauma and the lifetime severity of post-traumatic stress disorder each showed a link to faster ageing, and the researchers describe both links as small [2]. Two other things they tested, a post-traumatic stress disorder diagnosis and lifetime trauma exposure, showed no link at all [2].

Then there is the kind of stress most readers actually live with: work. A study published in 2025 followed 296 employed adults for a year. Work stress at the start predicted burnout and low mood a year later, but none of the four DNA-based age estimates the researchers measured was linked to work stress, to burnout, or to the stress hormones they measured in people's hair [3]. The stress did real damage over that year. It did not register on the clocks.

Can you undo it? Nobody has shown that you can. Every study behind this claim watches people rather than assigning them to more or less stress [1][2][3], so all of them can show that more-stressed people score older, and none of them can show that becoming less stressed makes anyone score younger.

There is also no single test of biological ageing to appeal to. Telomere length and the DNA clocks measure different things and can disagree about the same person, which is part of why one study finds a link and the next does not [2][3].

What the evidence does not cover:

• anyone whose stress was deliberately raised or lowered, because no study here did that
• men, in the 2004 telomere finding, which enrolled premenopausal women only [1]
• everyday pressure, in the pooled analysis, which measured childhood trauma and post-traumatic stress disorder rather than ordinary stress [2]
• whether any of these scores translate into illness or an earlier death, which none of these studies followed people long enough to see

If you are working on your stress, the case for doing it rests on burnout and low mood, which work stress did predict over a year in those 296 adults [3]. Whether it moves a cell-ageing score is a question nobody has run the study to answer.