The researchers believe the results can be extended to other stressful occupations.

Researchers at the University of Michigan conducted a study involving first-time interns. DNA analysis showed that their telomere shortening accelerated six times over the first year compared to normal progression. The work was published in the journal Biological Psychiatry.

Telomeres are the end sections of chromosomes, which are usually compared to protective caps because they keep the ends of chromosomes intact. However, because DNA polymerase is unable to synthesize a copy of the DNA from the very end, telomeres shorten with each division. Therefore, telomere length has been associated with a person’s lifespan and predisposition to disease. Last year, researchers at George Mason University showed that having children affects telomere length. Women who gave birth had shorter telomeres than women who did not have children. In addition, telomere shortening has been linked to cardiovascular disease and cognitive decline. Now researchers at the University of Michigan have decided to find out if there is a link between telomere length and stress.

For the experiment, they selected 250 interns who were entering their first year of practice at the hospital. The scientists took DNA samples before they started and after a year to compare how telomere length had changed. At the same time, they asked the volunteers to fill out a questionnaire that revealed the length of the work week and stress levels.

The authors observed that over the past 12 months, telomere length depletion in the interns accelerated six-fold compared to the average rhythm (from 6465.1 ± 876.8 base pairs to 6321.5 ± 630.6). Moreover, they highlighted a correlation between the number of work hours and the rate of acceleration. The standard work week includes 64 and a half hours, but some interns worked 80 hours a week. It was in them that telomere depletion progressed the fastest. The opposite trend was seen in those who chose the least busy schedule.

“Studies show that telomeres are indicators of aging and risk of various diseases, but this experiment suggests that their length also serves as a biomarker that reflects the effects of stress,” said one of the paper’s authors, psychiatrist Srijan Sen.

If this assumption is correct, the results obtained by the University of Michigan researchers could be extended to other stress-inducing professions.

Earlier, psychologists from the University of Michigan conducted a simple experiment that demonstrated that 20 minutes a day in nature is enough to significantly reduce cortisol levels.