Cellular ageing accelerated during internship: Research

From the long hours to the seemingly ever-present stress, internship is a challenging experience for most new doctors.
 
It can often feel like you start the year bright-eyed and bushy-tailed, only to end it as an exhausted, far older version of yourself.
 
Now new research confirms that internship does, in fact, age you.
 
Or, to be more accurate, research has found that the first year of being a doctor affects the length of your telomeres (the caps at the end of each strand of DNA that protect chromosomes).
 
Published in Biological Psychiatry, the research found that telomere length ‘shortened significantly’ over the course of internship.
 
‘Of note, the mean telomere attrition during internship year was six times greater than the typical annual attrition rate identified in a recent meta-analysis,’ the study states.
 
The longitudinal cohort study followed 250 interns in 55 American hospital systems during the 2015–16 academic year. On average, the interns in the study said they worked 64.5 hours a week.
 
The study found that longer work hours were associated with greater telomere loss over the year. In fact, the more the interns worked, and the more days they put in that were at or above 16 hours, the faster their telomeres shrank.
 
‘The responses given by some of the interns in these surveys indicated that some were averaging more than 80 hours of work a week, and we found that those who routinely worked that many hours had most telomere attrition,’ the study’s senior author Srijan Sen, a neuroscientist and psychiatrist who heads the Intern Health Study, said.
 
‘Those whose hours were at the lower end of the range had less telomere attrition.’
 
By contrast, the comparison group of 84 first-year undergraduate students experienced no telomere shrinkage, despite also having a stressful year of needing to cope with life at an elite institution of higher education.
 
‘The current model of intern-year training during residency increases trainee stress, which impacts their mental health and wellbeing,’ the study’s first author Dr Kathryn Ridoout, a psychiatrist at Kaiser Permanente in California, said.
 
‘These results extend this work and are the first to show that this stress reaches down to the biological level, impacting the well accepted marker of ageing and disease risk, telomere length.
 
‘I was particularly surprised to see the relation of number of hours worked to telomere shortening.’
 
This is not the first piece of research to discover potentially stressful events lead to telomere changes.
 
A study published in Human Reproduction last year found telomeres were shorter in mothers compared to women without children. The effect was so striking, study author and epidemiologist Anna Pollack said ‘it is equivalent to around 11 years of accelerated cellular ageing’.
 
Other research has explored ways in which you may be able to positively affect the length of your telomeres.
 
Exercising can help, with research published in Preventive Medicine in 2017 finding that being ‘highly active’ gives a biological advantage of nine years over people who are sedentary.
 
(It defined being ‘highly active’ as 30 minutes of jogging a day for women, and 40 for men).
 
Meditating may also play a role.
 
Research from 2012, published in The International Journal of Geriatric Psychiatry, found that meditating for 12 minutes increased telomerase activity when compared to being instructed to relax while listening to instrumental music.
 
That study found the meditation group showed a 43% improvement in telomerase activity, compared to 3.7% in the relaxation group.
 
However, finding the time to be highly active and engage in meditation while working as an intern may be easier said than done.
 
Consequently, it may be time to rethink the number of hours interns work.
 
That’s what Dr Ridout is hoping for.
 
‘Having completed residency myself and understanding the stress that can come with this training and extended work hours, I am hopeful these data can help inform the decisions of governing bodies that have been debating the importance of regulating resident work hours,’ she said.
 
‘Our results suggest that reforms in intern training and work hours with a renewed focus on wellbeing is necessary to protect the health and viability of our physician workforce.’

DNA internship telomere