The rigors of residency take their toll on future physicians

It’s the time of year when graduating medical students pour from the halls of academia and prepare themselves for their next challenge—residency training. But that first year of residency will most likely exact a heavy toll on their sleep, physical activity, and mood, according to results from a study published in the Journal of General and Internal Medicine.

“Though we expected the start of internship to affect sleep, mood, and activity, quantifying the extent and nature of the effects in real time really highlighted the magnitude of changes,” said senior author Srijan Sen, MD, PhD, associate professor of psychiatry, University of Michigan Medical School, Ann Arbor, MI. “The relationship between sleep and mood is clearly bidirectional, but it appears that sleep affects mood the next day more than mood affects sleep.”

Dr. Sen and colleagues undertook this prospective, longitudinal study to determine how the residency experience—notorious for sleep deprivation, inconsistent shift work, and little time for physical activity—affects first-year residents.

They gathered data from 33 first-year residents, from 2 months before their internship through the first 6 months of internship. Subjects wore accelerometry-based fitness-tracking devices (Fitbits®), which provided an objective real-time assessment of their daily sleep and physical activity. Researchers also conducted daily assessments of interns’ mood (scaled from 1 to 10) using SMS technology.

Data showed that after beginning their residencies, interns lost an average of 2 hours and 48 minutes of sleep per week (t=-3.04; P < 0.01), while their mood decreased by 7.5% (t=-3.67; P < 0.01) and their physical activity by 11.5% (t=-3.15; P < 0.01).

Researchers observed a bidirectional relationship between sleep and mood, with short sleep being predictive of a worse mood the next day (b=0.12; P < 0.001), which was then predictive of shorter sleep the next night (b=0.06; P=0.03). Notably, the effects of short sleep on mood was twice as high as the effects of mood on sleep.

Finally, researchers found that substantial shifts in the timing of sleep, such as sleeping 3 hours or more earlier or later than during pre-internship, led to shorter sleep (earlier: b=-0.36, P < 0.01; later: b=-1.75, P < 0.001). These shifts also brought about poorer mood (earlier: b=-0.41, P < 0.001; later: b=-0.41, P < 0.001).

When training physicians have to wake up earlier to start their duties in the hospital, most do not compensate by going to bed earlier the night before, noted Dr. Sen. He added that the practice of requiring interns to arrive at the hospital in the pre-dawn hours to update senior residents and attending physicians about patients during morning rounds dates back more than a century.

An update to this practice—considering all the new knowledge about circadian rhythm—is long overdue. The authors called for a redesign of shift schedules to increase the opportunities for sleep for these young people, and to allow them sufficient time to resynchronize their circadian rhythm.

“Interns’ schedules change day to day and month to month as they rotate through different shift times and settings, and with recent national changes in their work-hour limits, these dramatic changes in work and sleep time have become more profound,” he said. “We hope this research will help inform residency programs as they design their interns’ schedules.”

For this year’s residents, Dr. Sen offered some advice: “Try to stick to the same sleep-wake schedule throughout a rotation, and go to sleep earlier than you naturally would when your schedule demands an early start time, to reduce the effects of sleep deprivation and the risk of mood changes and depression.”

His hope is that hospitals will recognize the importance of sleep schedules, for both physicians and patients alike.

“We’re learning more and more that sleep and circadian timing play a role in our mental and physical health. We need to see this as a national priority, not just for physicians in training but even for those in practice–for instance, those who stay up late to finish entering information and orders into electronic health record systems at home, or have other administrative burdens outside of clinical care hours,” he concluded.

These are the first results from this project, which will continue. Dr. Sen and colleagues have recruited more than 500 people from the 2018 graduating class of 80+ medical schools for further study, including enhanced reports about their Fitbit results. From the class just matched into new residency programs, they will enroll 1,500 to 2,000 more subjects.

This study was funded by the National Institutes of Health (NIH) and the University of Michigan.

For more information about the study or to enroll, go to https://www.srijan-sen-lab.com/intern-health-study.