(From Betterhumans). With the caution that this is only a single study - and much more work needs to be done - psychological stress appears to be linked to shortened telomeres. These protective caps on the end of your chromosomes regulate the normal process of cell death, get shorter with age, and have been implicated as a cause of cancer. While we don't fully understand these mechanisms yet, it seems clear that having shorter telomeres is not a good thing. Chronic psychological stress is already linked with shorter life spans. Understanding why this is the case would be of great benefit, but it's too early to take this particular study at face value - the link to telomeres is tentative and much more work needs to be done.