New research shows just how stressful starting a new career as a doctor can be: stressful enough to have your DNA age six times faster than it normally would.
Scientists studying cellular ageing through DNA telomeres (the 'tips' of our chromosomes), which shrink as we get older, found that this natural shrinkage was happening at an accelerated rate among new doctors – the equivalent of six years' worth of shortening in just 12 months.
It's the first large, longitudinal study to look at the link between chronic stress and cell ageing, and the team behind the research says it could have implications for those in any high-pressure situation, from trainee soldiers to new parents.
"Research has implicated telomeres as an indicator of ageing and disease risk, but these longitudinal findings advance the possibility that telomere length can serve as a biomarker that tracks effects of stress," says one of the team, neuroscientist and psychiatrist Srijan Sen from the University of Michigan (U-M).
“研究表明端粒是衰老和疾病风险的一个指标，但这些纵向研究结果提出了端粒长度可以作为一种生物标志物来跟踪压力的影响的可能性，”研究小组成员之一、密歇根大学(University of Michigan)的神经学家和精神病学家斯里扬·森(Srijan Sen)说。
"It will be important to study how telomere changes play out in larger groups of medical trainees and in other groups of people subjected to specific prolonged stresses."
The researchers took DNA samples from 250 new doctors at the start and end of their first intern year. These were compared to samples from 84 U-M freshmen students. In addition, the team measured the participants' mental well-being and stress levels over time with the use of questionnaires throughout the year.
Besides "telomere attrition" being six times greater in the doctors, some other interesting findings came to light – for example, the longer hours the new doctors worked, the faster their telomeres shrank.