Does a surgeon’s sleep schedule affect how patients do after surgery?
In this prospective cohort study of 7,117 operations in France, 29.8 percent of operations performed by surgeons with social jet lag of 2 hours or more in the preceding month ended in a major adverse event, compared with 18.5 percent when the surgeon’s sleep timing shifted by less than an hour. After adjustment, that worked out to a relative risk 36 to 45 percent higher depending on the comparison group.
Social jet lag is a simple idea with a clunky name. It means the gap between when you sleep on workdays and when you sleep on your days off. If you wake at 6 a.m. for work but sleep until 9 a.m. on weekends, your body lives in two time zones at once. This study asked whether that mismatch in a surgeon’s life shows up in their patients’ outcomes.
How the study worked
Researchers followed 38 attending surgeons across 14 surgical departments in 7 specialties at 4 university hospitals in Lyon, France, between November 1, 2020 and December 31, 2021. The surgeons wore actigraphy devices continuously, so sleep was measured objectively rather than self-reported. Social jet lag was defined as the absolute difference between the midpoint of sleep on free days and the midpoint of sleep on workdays over the 30 days before each operation. A mismatch of 2 hours or more counted as severe. The outcome was a major adverse event within 30 days after surgery: inpatient death, prolonged ICU stay, reoperation, or severe complication.
This is an observational cohort study, not a trial. The models were adjusted for the surgeon’s sleep duration in the 24 hours and 30 days before the operation, midsleep time, age, sex, professional status, total working hours, night and on-call shifts, patient case mix, and time of incision, with a random effect for each surgeon.
What the data show
Across all 7,117 operations, 1,410 (19.8 percent) resulted in a major adverse event. Broken down by the surgeon’s social jet lag in the prior month, the rate was 18.5 percent when the shift was under 1 hour, 20.8 percent at 1 to 2 hours, and 29.8 percent at 2 hours or more. The 2-hour-or-more group was uncommon: 342 operations, 4.8 percent of the total, involving 7 surgeons.
After adjustment, operations by surgeons with 2 or more hours of social jet lag carried an adjusted relative risk of 1.36 (95% CI, 1.04 to 1.69) compared with under 1 hour, and 1.45 (95% CI, 1.12 to 1.81) compared with 1 to 2 hours.
Not every measure of irregularity behaved the same way. Midsleep time variability, the day-to-day standard deviation of sleep midpoint, was not associated with adverse outcomes: 60 minutes or more of variability gave an adjusted relative risk of 1.11 (95% CI, 0.93 to 1.28). Sleep duration was not associated either, whether measured in the 24 hours before the operation or averaged over 30 days.
The burnout finding ran in the same direction as social jet lag. Surgeons who screened positive for burnout on the Maslach Burnout Inventory had a median social jet lag of 75 minutes versus 52 minutes in those without burnout (p = .04), and median midsleep time variability of 54 versus 43 minutes (p = .01).
Dr. Kumar’s Take
As a surgeon, this one lands close to home. I tend to think about total hours of sleep, as if clearing some nightly threshold means everything is fine. This study says timing matters independently of quantity: sleep duration showed no association with patient outcomes, while the workday-to-free-day mismatch did.
I want to be careful with how far I push it. This is observational, so it shows a link, not proof that circadian misalignment caused the complications. The severe social jet lag group was small, 7 surgeons and under 5 percent of operations, and the confidence interval against the under-1-hour group nearly touches 1. Busier surgeons may have both messier schedules and harder cases, though the models did adjust for patient mix, working hours, and night shifts. What makes me take it seriously is that the burnout signal moved in the same direction, and that the effect held after sleep duration was accounted for.
Why consistent timing matters
Your internal clock controls more than sleepiness. Sleep timing regularity is what keeps the clock entrained, and it has been linked to better cognitive performance in the general population. When sleep timing jumps around, the clock never fully syncs, and the body behaves a little like it is permanently jet-lagged from travel. The encouraging side of this is that timing is something you can influence more easily than total workload. Going to bed and waking at similar times, even on days off, may protect performance in a way that simply sleeping in cannot.
Practical Takeaways
- Try to keep your sleep timing within about an hour across workdays and days off, since that was the group with the lowest event rate in this study.
- If your job forces shifting hours, treat consistent sleep timing as a real safety habit, not a luxury, and protect it the way you would protect any other part of your work.
- Watch for burnout warning signs like constant fatigue or short temper, because surgeons with burnout in this study had larger workday-to-free-day sleep shifts.
- Remember that total sleep and sleep timing are two different things. In this cohort, sleep duration showed no association with patient outcomes while social jet lag did.
Related Studies and Research
- Social jet lag: how mismatched sleep schedules increase metabolic disease risk
- High-glycemic carbohydrate meals shorten sleep onset time
- Irregular sleep patterns linked to poor academic performance in college students
- Sleep duration and dementia risk: 7 hours protects your brain long-term
FAQs
What exactly is social jet lag?
Social jet lag is the difference between your sleep schedule on workdays and your sleep schedule on free days. In this study it was measured precisely: the absolute difference between the midpoint of sleep on free days and the midpoint of sleep on workdays. The name comes from how the feeling resembles the grogginess of flying across time zones, except you never left home. If you wake early during the week but sleep much later on weekends, your body clock keeps getting pushed back and forth, even when your total hours look adequate.
Does this mean I should never sleep in on my days off?
Not necessarily, but this research suggests a large weekend shift may carry a cost. In the surgeons with 2 or more hours of social jet lag, sleep on free days ran from 1:27 a.m. to 9:54 a.m., against 11:26 p.m. to 6:15 a.m. on workdays. That is a wholesale relocation of the night, not a lie-in. A gentler approach is to keep your wake-up time closer to your usual time, then rest or nap later if you need more sleep.
Should patients worry about their surgeon’s sleep?
This study is a reason for the medical field to take surgeon scheduling seriously, not a reason to interrogate your surgeon before an operation. The findings point to system-level fixes, like more predictable shifts and better fatigue policies, rather than blaming individuals. A single observational study cannot tell you anything about one specific surgeon. The broader lesson applies to everyone: irregular sleep timing appears to affect performance in work that demands precision.
Bottom Line
In 7,117 operations performed by 38 surgeons, major adverse events occurred in 29.8 percent of operations by surgeons with 2 or more hours of social jet lag in the preceding month, compared with 18.5 percent when the surgeon’s sleep timing shifted by less than an hour. Sleep duration showed no such association. The takeaway reaches well beyond the operating room: consistent sleep timing, not just total hours, appears to support the focus and steadiness that demanding work requires.
