Is a lack of sleep impacting our performances at work?
It’s a common question asked. And one that appears even more critical for high-stakes environments like surgery. But a new study from French researchers suggests we might be asking the wrong question when it comes to sleep.
Their study evaluated “social jet lag” – the discrepancy in sleep timing rather than duration, finding that patients of surgeons experiencing substantial social jet lag of two or more hours had a significantly higher risk of major adverse events.
The researchers monitored the sleep of 38 experienced surgeons in France, using “midsleep” time – the midpoint between bed time and waking up – recorded via wearable sensors to compare sleep consistency on work days and days off.
Social jet lag was defined by the researchers as the absolute difference between average midsleep times on work days and days off in the month before surgery.
Over the month, surgeons slept an average of 6 hours and 57 minutes (6 hours 37 minutes on work days versus 7 hours 42 minutes on days off), with an average midsleep time of 3.05am (average bed time 11.18pm and wake-up time 6.52am).
The median midsleep time variability was 42 minutes and the median social jet lag was 51 minutes.
Of the 7117 operated patients (mean age 56, 55% female), as many as one in five experienced a major adverse event (death or complication) across digestive, orthopaedic, gynaecologic, urologic, cardiac, thoracic, and endocrine surgeries.
A social jet lag of two or more hours resulted in a 36-45% increased risk of major adverse events compared with less than one hour or 1-2 hours respectively, according to the findings published in JAMA Surgery [link here].
This was independent of sleep duration, total working hours, and night shift frequency, none of which independently predicted surgical outcomes, suggesting that sleep regularity alone might be a stronger determinant of performance.
Eight surgeons recorded burnout on the self-administered Maslach Burnout Inventory questionnaire. These surgeons had greater social jet lag (median 75 minutes) and greater sleep-timing variability (54 minutes) than their peers.
The researchers concluded that maintaining a regular sleep schedule throughout the week might play an important but under-recognised role in surgical safety, but conceded work scheduling such as frequent night shifts made this difficult.
“Given the high prevalence of preventable adverse events and surgeon burnout, promoting circadian-aligned behaviours and more consistent sleep schedules at individual and institutional levels may offer an actionable opportunity to enhance surgeon professional well-being and improve patient outcomes,” they said.
They suggested morning light exposure, time-restricted eating, moderate-intensity aerobic exercise and breath work as circadian-aligned behaviours. They also suggested self-monitoring with wearable devices, tailored sleep education and work-scheduling that took into account individual chronotypes.
In an invited commentary [link here], US trauma surgeons said there had been a recent perspective shift from prioritising sleep duration among surgeons through strategies such as napping and increasing sleep on days off to the importance of sleep regularity.
They explained the shift was driven by emerging evidence that suggested regularity as opposed to duration appeared “as important and potentially more important” for cardiometabolic health, mood regulation, and cognitive performance.
The study’s findings should “serve as a wake-up call”, they added.
“Irregular sleep schedules disrupt circadian alignment and contribute to downstream physiological dysregulation. These findings support a multidimensional view of sleep health, with sleep regularity as an important target for interventions,” they said.