Looks to be some pretty early and basic research, but still interesting.

The link between stress, ageing and health at the cellular level is unclear, but a team led by Elissa Epel of the University of California at San Francisco, US, has now looked at the effect of stress on the cell.

A piece of DNA called a telomere caps the ends of each chromosome, protecting those ends and promoting genetic stability. Each time a cell divides, the telomeres shorten so that daughter cells have slightly shorter telomeres than their parents.

But in young people, an enzyme called telomerase corrects the process, regenerating the ends. However, in older people the telomeres shorten significantly and eventually their replication stops altogether.

In this small study, women who reported the most stress had the shortest telomeres, suggesting the link between stress and the cellular ageing process.

For more details see this article from New Scientist.